# Pop ups and windows. Your thoughts.



## Andyshine77 (Dec 18, 2011)

Not so long ago they were all the rage. why? There was never an ounce of proof they did much of anything positive in most cases.

I could never understand piston windows in closed port saws doing anything other than dropping case pressure. Some said it helps deal with heat, I have a hard time swallowing that pill. 

Unless you have enough material and a severely compression challenged top end, I've seen little gains with pop ups in most work ported saws. To be completely honest I've seen things go the other way more than once, even when port timing numbers were kept the same. The 372 seems to be one of the saw where pop ups are advantageous, and I think I know why.

So what say the masses, and people with larger mental capacity than myself?? The more scientific the better. 

Keep in mind this is about work saws, not high end competition saws.

Andre.


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## Jacob J. (Dec 18, 2011)

I like having windows in my pickup, so I can see where I'm going.


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## parrisw (Dec 18, 2011)

I've wondered too. I'm pretty certain they both work in 372's, I've tried with and without and they seem to run better with them.


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## Jacob J. (Dec 18, 2011)

Andre- 

If you have any doubts about windows, try putting a Husky 380 piston in a Stihl 064 and see how much you lose
in terms of top RPM. I think you'll lose around 3-4 grand. Just a hunch.


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## wigglesworth (Dec 19, 2011)

I don't really like pop-ups, but in some cases, it's all u can do to get the comp up to respectable levels. I have not noticed "huge gains" in the saws I've done with em. Also creates lots of turbulence across the crown surface. 

As for windowing pistons, I really don't see a need in it, other than lightening a slug a bit. In saws like the 372, where the serve no purpose in opening another point to help feed the transfers, I don't understand why folks do it. Now in older conventional jugs, with the lower trans in the side of the jug, it makes sense to have em there, as they will flow mix thru the windows into the transfers as the crankcase pressure increases. 

But then again, what do I know......:dunno:


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## Dennis Cahoon (Dec 19, 2011)

You can get all the compression you need in a work saw without using a pop-up piston. IMO a waste of time! The original pop-up design was used with a domed piston to pump up high compression for an alcohol running stock appearing racesaw without making a removeable head.


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## parrisw (Dec 19, 2011)

Dennis Cahoon said:


> You can get all the compression you need in a work saw without using a pop-up piston. IMO a waste of time! The original pop-up design was used with a domed piston to pump up high compression for an alcohol running stock appearing racesaw without making a removeable head.



Yes, if your setup to cut the squish band. I have not ventured into that yet, I guess I should give it a go some day.


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## parrisw (Dec 19, 2011)

What about cutting a domed piston as apposed to a popup where just the center is rised. That would eliminate the turbulence caused by the popup.


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## tree monkey (Dec 19, 2011)

Andyshine77 said:


> Not so long ago they were all the rage. why? There was never an ounce of proof they did much of anything positive in most cases.
> 
> I could never understand piston windows in closed port saws doing anything other than dropping case pressure. Some said it helps deal with heat, I have a hard time swallowing that pill.
> 
> ...





parrisw said:


> What about cutting a domed piston as apposed to a popup where just the center is rised. That would eliminate the turbulence caused by the popup.


the ms 260 is domed, and i cut it flat


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## parrisw (Dec 19, 2011)

tree monkey said:


> the ms 260 is domed, and i cut it flat



Why?


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## Andyshine77 (Dec 19, 2011)

One reason I made this thread is the fact I have done a few experiments, and have seen the results, in most cases my thinking was right, but not always. Something I also see done on work saws, is a lot of lower transfer work. Without carb and other intake work, it seems you loose some top end. You need pressure/volume to push the charge through the transfer, make the lowers too big the charge just sits in the case or transfers. Sometimes smaller is better. Just thinking out loud here.


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## tree monkey (Dec 19, 2011)

parrisw said:


> Why?



because it works


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## Andyshine77 (Dec 19, 2011)

wigglesworth said:


> I don't really like pop-ups, but in some cases, it's all u can do to get the comp up to respectable levels. I have not noticed "huge gains" in the saws I've done with em. Also creates lots of turbulence across the crown surface.
> 
> As for windowing pistons, I really don't see a need in it, other than lightening a slug a bit. In saws like the 372, where the serve no purpose in opening another point to help feed the transfers, I don't understand why folks do it. Now in older conventional jugs, with the lower trans in the side of the jug, it makes sense to have em there, as they will flow mix thru the windows into the transfers as the crankcase pressure increases.
> 
> But then again, what do I know......:dunno:



This is 100% correct IMHO.


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## tree monkey (Dec 19, 2011)

Andyshine77 said:


> One reason I made this thread is the fact I have done a few experiments, and have seen the results, in most cases my thinking was right, but not always. Something I also see done on work saws, is a lot of lower transfer work. Without carb and other intake work, it seems you loose some top end. You need pressure/volume to push the charge through the transfer, make the lowers too big the charge just sits in the case or transfers. Sometimes smaller is better. Just thinking out loud here.



most people over port a cylinder to be a good worksaw


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## Jacob J. (Dec 19, 2011)

tree monkey said:


> because it works



Do you cut the squish band in the cylinder flat as well?


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## tree monkey (Dec 19, 2011)

Jacob J. said:


> Do you cut the squish band in the cylinder flat as well?



yes


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## Terry Syd (Dec 19, 2011)

A domed piston makes sense, there won't be anything in the way to upset the transfer flow. The domed piston may run a bit hotter as the crown has more area, but that is nothing compared to the crown area of the pop-up.

Has anybody run into a pop-up piston in any other two-stroke sport or application? I can't recall seeing it in any kart or aero engines. It seems to be a mod only used by chainsaw enthusiasts.


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## tree monkey (Dec 19, 2011)

Terry Syd said:


> A domed piston makes sense, there won't be anything in the way to upset the transfer flow. The domed piston may run a bit hotter as the crown has more area, but that is nothing compared to the crown area of the pop-up.
> 
> Has anybody run into a pop-up piston in any other two-stroke sport or application? I can't recall seeing it in any kart or aero engines. It seems to be a mod only used by chainsaw enthusiasts.



a domed piston does upset transfer flow. the transfer port roof angle has to be right also


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## Terry Syd (Dec 19, 2011)

Perhaps were not talking about the same kind of dome. I'm referring to the dome type pistons you find in motorcycles, that is, a slow curve on the top of the piston.

If you take a look at Blair's work, you will see a graph of the actual flow directions of the ports. The transfer flows tend to naturally flow upward from the port angles by about another 15 degrees. The up angle is even more when the port first opens. The same thing exists for the back angle, the actual flow is more towards the back of the port than the port angle.


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## wigglesworth (Dec 19, 2011)

Terry Syd said:


> Has anybody run into a pop-up piston in any other two-stroke sport or application? I can't recall seeing it in any kart or aero engines. It seems to be a mod only used by chainsaw enthusiasts.









The 028 super has one stock, and IMHO, is the ideal shape to keep flow disruption to a minimum.


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## tree monkey (Dec 19, 2011)

Terry Syd said:


> Perhaps were not talking about the same kind of dome. I'm referring to the dome type pistons you find in motorcycles, that is, a slow curve on the top of the piston.
> 
> If you take a look at Blair's work, you will see a graph of the actual flow directions of the ports. The transfer flows tend to naturally flow upward from the port angles by about another 15 degrees. The up angle is even more when the port first opens. The same thing exists for the back angle, the actual flow is more towards the back of the port than the port angle.



what was done in the 70's and what is done today are 2 different things. i've read blair's and jenning
s books. i also have porting software that says thay were not always right. but still worth reading


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## Andyshine77 (Dec 19, 2011)

tree monkey said:


> a domed piston does upset transfer flow. the transfer port roof angle has to be right also



Precisely how it works IMHO.


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## tree monkey (Dec 19, 2011)

Andyshine77 said:


> Precisely how it works IMHO.



if a domed piston is the best, then why don't the oem's do it to all there saws?


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## Andyshine77 (Dec 19, 2011)

tree monkey said:


> if a domed piston is the best, then why don't the oem's do it to all there saws?



That's a good question? I guess I need to read through Jenning again.:smile2:


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## Terry Syd (Dec 19, 2011)

I just went back and checked my memory of Blair's work. I got it wrong for the back angle, it tends to be more towards the exhaust port than the rear of the cylinder.

Here's a link to Blair's work - Design and simulation of two-stroke engines Gordon P. Blair.pdf - 4shared.com - document sharing - download

The discussion of transfer flows is on pages 264 & 265. The graphs are numbers 3.35 and 3.36


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## Andyshine77 (Dec 19, 2011)

Thanks for the link.


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## Terry Syd (Dec 19, 2011)

This about the fourth or fifth time I've put the link on this forum, you must have missed the other times. I went ahead and downloaded the document on my computer so I have it available for easy access.


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## tree monkey (Dec 19, 2011)

Terry Syd said:


> This about the fourth or fifth time I've put the link on this forum, you must have missed the other times. I went ahead and downloaded the document on my computer so I have it available for easy access.



i'm sure blair was the best in his time. but look at a 70's 250 dirtbike. no matter what you do to the porting, it would not compair to todays 250 stock. also his port grafs are for over square engines, chainsaws are under square.
i've done alot of wild things to chainsaws, and one thing i know is popups are not the ticket


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## parrisw (Dec 19, 2011)

tree monkey said:


> because it works



Hmm, well, that explains everything then. Thanks for the help!


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## Terry Syd (Dec 19, 2011)

Treemonkey, I think you are confusing Bell with Blair. Bell's work was rather simplified, he didn't even use time/area, only timing figures. Blair on the other hand is at the engineering level.

If you take a look at Blair's work you will find a reference to 'Loopsaw'. That is a chainsaw engine that he uses for comparative work. He even does some modification of Loopsaw in one of his chapters (towards the end I think). Whereas Jennings time/area is relevant to oversquare piped engines, chainsaws are a different animal. I was able to glean a real nugget of information from Blair's work for the time/area of transfers on chainsaws.

Timberwolf had stated that he found a time/area for transfers less than the bottom range of Jennings formulas and charts to work for chainsaws. When I found Blair's reference to chainsaw transfer time/area he confirmed what Timberwolf said with an actual number to work with - I won't ruin the surprise, you can find it with the link.


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## Justsaws (Dec 19, 2011)

A graciously curved fitted top over a well windowed waist sitting atop a full skirt, piston ####.


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## Terry Syd (Dec 19, 2011)

Sounds very feminine when you put it that way.


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## chainsaw kid (Dec 19, 2011)

wigglesworth said:


> The 028 super has one stock, and IMHO, is the ideal shape to keep flow disruption to a minimum.



028 super is a great saw, done up even better...torquey too! Problem is the comparable saws today blow it away and most people would laugh at an 028. Thats why it's always good to have the sleeper no one wants to steal. Pull it out and blow by the guy with the expensive saw. 
That dome piston in that saw, I too like that design. The shape of the combustion chamber, location of the spark plug, dome piston, high compression....and they are still running 25-35 years later... Lets see how the new saws hold up 25-35 years from now.

Sorry for the slight derail.

Kevin


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## AUSSIE1 (Dec 19, 2011)

So Andy, what's your thoughts/experiences?

A popup can be worked beyond your typical lathe spin. Sometimes the gains can out weight the negs. For me a reworked popup piston with top ring pin shifted for a wider port and one ring on a windowed piston (not that I care for windows) produces more than I can get from a kit piston. Very few have the means to access a popup let alone further machining methods. For sure you see some lowers over worked to the point you could see they would struggle with velocity.


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## AUSSIE1 (Dec 19, 2011)

tree monkey said:


> if a domed piston is the best, then why don't the oem's do it to all there saws?



Just like other mods we do to gain up to 40 odd % over OEM's


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## blsnelling (Dec 19, 2011)

My 440/460 *majorly *came alive with the popup. It was the last thing added, and nothing else was done at that time. My 372BB didn't really come alive until I windowed the piston and raised the cylinder wall on the sides. I don't think you can just make a general statement about either mod. It depends on the saw.


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## mdavlee (Dec 19, 2011)

I don't like adding windows to a 372 cylinder. A popup did make the 2171 gain a lot more over standard porting .I want to cut the squish band and see how one does that way. The 2171 had the least work done and the strongest runner i've turned out.


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## blsnelling (Dec 19, 2011)

I don't currently have windows in my 390XP piston. I plan on adding them once I'm done with everything else. That way I'll be able to tell if that mod alone made a difference. The 385XP that I did for WYK has a windowed piston. It made an awesome runner. From what I understand, this is not a new mod and has been used in the past by numerous different builders.


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## wigglesworth (Dec 19, 2011)

blsnelling said:


> My 440/460 *majorly *came alive with the popup. It was the last thing added, and nothing else was done at that time.



U should had gained a lot of intake of u turned the top down and milled the base.


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## blsnelling (Dec 19, 2011)

wigglesworth said:


> U should had gained a lot of intake of u turned the top down and milled the base.



Probably about 3*. That's a by product anytime you do a popup.


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## ECsaws (Dec 19, 2011)

"MY" findings... pop-ups do indeed make gains in a chainsaw motor .. Now "I" find a lot depends on how the pop-up is done if you cut a square edge gains are not so much but a nice gradual rounded edge seem to work better for "ME".
In some cases I have seen saws go in reverse from to much compreshion... then again to much depends on what saw your working on, seems everyone likes something a little differnt. 
My take on windows . In "theory" they should "help" cool the piston crown. also cutting windows dose reduced piston weight, witch dose lighten the rotating mass witch "should" result in a quicker spool up but possible lose in tourque. negatives to windows is of course the obvious increasing the case volume, depending on what you do to the transfers how much affect windowing dose. One other thing on windowing I've always wondered when the windows pass the upper transfers what happens? is the pressure causing a reverse pressure affect on how the transfer feed ? I havent found any measurable gains (in a GAS saw) in windowing a non windowed piston, I honistly thing those engineers who designed that piston/ cly... know a heck of a lot more than I do......
Without CCing the case volume and doing all the math, doing any off this is like shooting in the dark unless your willing to do all the testing witch trust me get real pricey real quick...


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## wigglesworth (Dec 19, 2011)

blsnelling said:


> Probably about 3*. That's a by product anytime you do a popup.



No, not everytime


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## blsnelling (Dec 19, 2011)

wigglesworth said:


> No, not everytime.



 039?


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## wigglesworth (Dec 19, 2011)

blsnelling said:


> 039?



Actually, that one is the first one I did, a partner 5000 slug. The 039 will be done today though


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## sps3172 (Dec 19, 2011)

Hi Guys....

Does anyone actually have and use a steady state (not inertial) load type, dyno(water break, eddy current, etc)? It seems that there are lots of great ideas floating around the forums.....but no real way to test for the small gains.

I found some OOOOLLLLLDDD threads where it seems that Walker's Saw Shop was testing with a Land and Sea water brake.....but I don't hear anyone talking about that sort of testing these days.


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## Terry Syd (Dec 19, 2011)

A Works Connection tach can be installed on the saw for less than $40. You can monitor the tach when you make a change to the saw. It is hard to pick up a couple of hundred rpm with your ears or by subjective feel, but the tach is an objective indicator that can tell you if you are making progress or just fooling yourself.


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## sps3172 (Dec 19, 2011)

Terry Syd said:


> A Works Connection tach can be installed on the saw for less than $40. You can monitor the tach when you make a change to the saw. It is hard to pick up a couple of hundred rpm with your ears or by subjective feel, but the tach is an objective indicator that can tell you if you are making progress or just fooling yourself.



Terry,

Was this in response to my question about using steady state dynamometers?

- Steve


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## Terry Syd (Dec 19, 2011)

Yep, I haven't heard of any dynos available for saws. The tach is something everybody can have access to.


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## sps3172 (Dec 19, 2011)

Terry Syd said:


> Yep, I haven't heard of any dynos available for saws. The tach is something everybody can have access to.



I agree that there don't seem to be any 'bolt on' solutions for chain saw dynamometers. That being said, there are many small engine brakes available....and the software to 'watch' them. It's down to a matter of making the fixtures to interface the saw engine with the brake. As mentioned in my first post, it seems that at one time, Walker's Saw Shop was using a land and sea water brake for testing. I found this info searching old posts. At some point ('03-'04??) all discussion of this dyno and their testing stopped. I'm just wondering how/why that sort of testing fell out of favor.

I suppose the tach is better than nothing....but logic suggests that it's not better by much. Using a saw is a 'subjective' activity. Cutter pushes harder one time....softer the next. One time the chain has 'x' sharpness.....next time it's 'x+ or - y'. One time the wood is 'x' hardness.....next time it's 'x+ or - y'. Etc.

If the outcome of the cut (time, typically) can be impacted/skewed by all the variables above (operator, chain, wood), then the 'data' provided by the tach can be skewed in the same way.


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## spacemule (Dec 19, 2011)

sps3172 said:


> I agree that there don't seem to be any 'bolt on' solutions for chain saw dynamometers. That being said, there are many small engine brakes available....and the software to 'watch' them. It's down to a matter of making the fixtures to interface the saw engine with the brake. As mentioned in my first post, it seems that at one time, Walker's Saw Shop was using a land and sea water brake for testing. I found this info searching old posts. At some point ('03-'04??) all discussion of this dyno and their testing stopped. I'm just wondering how/why that sort of testing fell out of favor.
> 
> I suppose the tach is better than nothing....but logic suggests that it's not better by much. Using a saw is a 'subjective' activity. Cutter pushes harder one time....softer the next. One time the chain has 'x' sharpness.....next time it's 'x+ or - y'. One time the wood is 'x' hardness.....next time it's 'x+ or - y'. Etc.
> 
> If the outcome of the cut (time, typically) can be impacted/skewed by all the variables above (operator, chain, wood), then the 'data' provided by the tach can be skewed in the same way.



You make too much sense. Ask these guys--all they need is a decibel meter to tell how fast their saw is. :hmm3grin2orange:


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## Log Hogger (Dec 19, 2011)

Could use a water pump. Pipe the water up vertically and into a barrel, then measure gallons/minute. By adjusting the height of the head you could find the right load range. Then it's down to the matter of determining which mods give the best head.


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## sps3172 (Dec 19, 2011)

Log Hogger said:


> Then it's down to the matter of determining which mods give the best head.



Thoughts like this display the whole 'engine mod' thing in a whole new light. 


Sorry....I grew up on Beavis and Butthead.


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## showrguy (Dec 19, 2011)

Then it's down to the matter of determining which mods give the best head. 

i'm not sure, but some of the site moderators might get pissed at you for that statement !!!


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## parrisw (Dec 19, 2011)

So far there are allot of opinions floating around here. The OP started this, so lets hear what he thinks!


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## parrisw (Dec 19, 2011)

ECsaws said:


> "MY" findings... pop-ups do indeed make gains in a chainsaw motor .. Now "I" find a lot depends on how the pop-up is done if you cut a square edge gains are not so much but a nice gradual rounded edge seem to work better for "ME".
> In some cases I have seen saws go in reverse from to much compreshion... then again to much depends on what saw your working on, seems everyone likes something a little differnt.
> My take on windows . In "theory" they should "help" cool the piston crown. also cutting windows dose reduced piston weight, witch dose lighten the rotating mass witch "should" result in a quicker spool up but possible lose in tourque. negatives to windows is of course the obvious increasing the case volume, depending on what you do to the transfers how much affect windowing dose. One other thing on windowing I've always wondered when the windows pass the upper transfers what happens? is the pressure causing a reverse pressure affect on how the transfer feed ? I havent found any measurable gains (in a GAS saw) in windowing a non windowed piston, I honistly thing those engineers who designed that piston/ cly... know a heck of a lot more than I do......
> Without CCing the case volume and doing all the math, doing any off this is like shooting in the dark unless your willing to do all the testing witch trust me get real pricey real quick...



I've seen some pics of popups as well that had a harsh uprise to them, or square! Don't know why they'd do that. 

Here is a 460 piston that I did, this is how much I "chamfer" them.






I've heard the disruption of flow theory many times. Has anyone actually tested it to see if its true? I mean the only way you'd know is with a high speed camera and see how air flows across the top of the piston.


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## Dennis Cahoon (Dec 19, 2011)

parrisw said:


> I've heard the disruption of flow theory many times. Has anyone actually tested it to see if its true? I mean the only way you'd know is with a high speed camera and see how air flows across the top of the piston.




Isn't all about disruption in the right direction???????......Hahahahahahaha!


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## Dennis Cahoon (Dec 19, 2011)

parrisw said:


> Imagin that piston originally having a dome......them gradually cutting in your pop-up.


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## parrisw (Dec 19, 2011)

Dennis Cahoon said:


> Isn't all about disruption in the right direction???????......Hahahahahahaha!



??????? not sure what you mean.


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## parrisw (Dec 19, 2011)

Dennis Cahoon said:


> parrisw said:
> 
> 
> > Imagin that piston originally having a dome......them gradually cutting in your pop-up.
> ...


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## parrisw (Dec 19, 2011)

Here is a 2 stroke piston, what say you on flow across the piston with this.


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## Dennis Cahoon (Dec 19, 2011)

That's right!.....a domed pop-up.......makes a BadA$$ Racesaw......Work saw, a waste of time!


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## Jacob J. (Dec 19, 2011)

parrisw said:


> Here is a 2 stroke piston, what say you on flow across the piston with this.



The piston in my old Clinton saws looks similar to that. I've heard those being called a "wave separator" style piston. 
The Clinton piston is ramped more towards the exhaust ports and has a shelf on the intake side. 

Pretty much all of Stihl's pro-grade models in the 70's used domed pistons at one point or another with the exception
I believe being the 090. But they did a lot of playing around with combustion chamber shapes and sizes on the 090.


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## parrisw (Dec 19, 2011)

Dennis Cahoon said:


> That's right!.....a domed pop-up.......makes a BadA$$ Racesaw......Work saw, a waste of time!



Ok fair enough. I really respect your thoughts and opinions, but why is it a waste of time? 



Jacob J. said:


> The piston in my old Clinton saws looks similar to that. I've heard those being called a "wave separator" style piston.
> The Clinton piston is ramped more towards the exhaust ports and has a shelf on the intake side.
> 
> Pretty much all of Stihl's pro-grade models in the 70's used domed pistons at one point or another with the exception
> I believe being the 090. But they did a lot of playing around with combustion chamber shapes and sizes on the 090.



I was always under the assumption that the ramps direct intake flow up into the combustion chamber so it doesn't just flow straight out the exhaust.


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## srcarr52 (Dec 19, 2011)

IMHO a pop-up is a band-aid on a hard to solve problem. The factory combustion chamber on stock saws are too large for emission and reliability reasons. A lower compression engine is less finicky about carb tuning and proper fuel. Without welding in the combustion chamber, cutting the squish band, or making a two piece head (all three are difficult processes) the only other solution is to create a pop-up. 

A decent pop-up will bring the compression into respectable range for higher octane fuel (premium only) and the saw can still be just as reliable with a little more attention to the proper carb tuning. Yes a pop-up does cause issues with flow, heat distribution across the dome and flame propagation but the benefits of compressing the air fuel mixture closer to it's ideal cycle will out way the losses from them. Of course things can be done to minimize the losses by making a smooth transition from the pop-up to squish area of the piston, matching this area as close to the dome of the cylinder as possible to stop predetonation and hopefully not mess too much with the flame propagation. I like to have the clearance of the pop-up at the base close to my squish number and gain about 0.040"-0.060" of clearance on it's way up, also putting a healthy radius at the top to keep the piston from getting a hot spot. 

I'm not sold on windows in pistons. Obviously for a cylinder with lower transfer ports in the cylinder wall they are necessary but for a base inlet transfer port I don't know if they actually have any flow benefits, maybe even a detriment due to the two flow paths converging causing turbulence. The lightening of the piston, and the added removal of heat are always a good thing thought. The 372 I built I put windows in and it is a great runner but I didn't get time to test it in stages so I have nothing to compare against. This is something I would like to study when I get my dyno running (hydraulic pump with a throttle valve kart engine dyno).


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## Terry Syd (Dec 19, 2011)

Steve, I agree that the tach isn't the best device for recording objective information, but it is all we have. A saw, stuck on a log and allowed to self feed into that log will give an rpm read out. If we tweak the HS needle, we may get another couple hundred rpm in that cut. Now 200 rpm at 10,000 rpm is only 2%. Most people would never pick up a 2 % change, but the tach can.

We can use the tach to find things like peak horsepower (best cutting speed), the rpm of peak torque, the width of the powerband and at what rpm the saw wants to bog. If we make a mod to the engine, we can see if any of those reference points change and by how much (and record them for future work)

It ain't the best, but it beats listening to the sounds of a muffler mod (ie: "sounds bad azz")


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## stihl038x2 (Dec 19, 2011)

Here is a Dyno, he talks about it in one of his other vids, but I couldn't find it.

Steve

<iframe width="560" height="315" src="http://www.youtube.com/embed/H0gLFuT9aW4" frameborder="0" allowfullscreen></iframe>


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## RTK (Dec 19, 2011)

Terry Syd said:


> Yep, I haven't heard of any dynos available for saws. The tach is something everybody can have access to.



I've seen more than one dyno that has been set up for a saw or other 2 stroke applications. Most that have them tend to be pretty tight lipped when it comes to doling out data and from what they have shown not all that hard to make your own.


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## sachsmo (Dec 19, 2011)

On the old "clamshell" design, a welded pop-up is a good option.

For a race saw/toy.

Would not use one on a "work" saw.


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## parrisw (Dec 19, 2011)

Ok, you guys talked me into trying to cut squish bands. Here is a start.

Got a center pilot hole drilled so far and squared up the piece of alu stock. Now just have to lay out the cylinder mounting holes and get some long bolts.


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## wyk (Dec 19, 2011)

<iframe width="420" height="315" src="http://www.youtube.com/embed/zwdMSCJULgU" frameborder="0" allowfullscreen></iframe>

That comes out to a little short of 20hp, folks.


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## Dennis Cahoon (Dec 19, 2011)

wyk said:


> <iframe width="420" height="315" src="http://www.youtube.com/embed/zwdMSCJULgU" frameborder="0" allowfullscreen></iframe>
> 
> That comes out to a little short of 20hp, folks.




......that's the trouble with dnyo's!......people Bull$hit you about how much hp they're making to sell their products.......064 with 20hp.....Hahahahahahaha!


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## Dennis Cahoon (Dec 19, 2011)

parrisw said:


> ......but why is it a waste of time?
> 
> 
> I already told you in post #6.........IMO......"You can get all the compression you need in a work saw without using a pop-up piston."


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## Andyshine77 (Dec 19, 2011)

AUSSIE1 said:


> So Andy, what's your thoughts/experiences?
> 
> A popup can be worked beyond your typical lathe spin. Sometimes the gains can out weight the negs. For me a reworked popup piston with top ring pin shifted for a wider port and one ring on a windowed piston (not that I care for windows) produces more than I can get from a kit piston. Very few have the means to access a popup let alone further machining methods. For sure you see some lowers over worked to the point you could see they would struggle with velocity.



My experience is limited, that's why I wanted to hear from people with more experience. 

One thing I don't like is jumping on the bandwagon and doing something that has zero proof it actually works. Windows in pistons that have cylinders with bottom feeding transfers, simply does not work. The only thing I can see the windows doing in these cylinders is forcing some charge back down the transfers, plus unwanted turbulence, just like EC said. 

Obviously compression is an issue with some saw, we know that. Do pup ups work? yes and no, IMHO it all depends on the design of the saw and the stock compression numbers, if you can get decent compression numbers by simply setting squish, you're good to go. What good does an extra 10psi really do in a work saw that already has 175psi? add to that you no longer have a plug and play top end.

So far this thread has been informative. Keep your minds open guys, don't stick to one idea just because. Every engine is different, and responds to different things.


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## parrisw (Dec 19, 2011)

Dennis Cahoon said:


> parrisw said:
> 
> 
> > ......but why is it a waste of time?
> ...


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## komatsuvarna (Dec 19, 2011)

My expierence is *very* limited, but I guess Ill spit it out. In my expierence, piston windows in a 372 does nothing good. I know everybody ports different, and that may be why my expierence was different, but I won't be doing another windowed 372.......

Popups, Ive only done a few, haven't had one go backwards yet. I will say that I think it does disrupt flow, but maybe the added compression off-sets the flow disruption. I guess it depends A LOT on the saw too. Some of the Huskys (372 namely) are known for being a little on the lower side. I also had a damn good runner, that only blowed 130psi.....

EDIT, I don't have a picture of any my popups I don't think, But I lay the edges way back, looks more like a slight bubble.


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## one.man.band (Dec 19, 2011)

sorry...don' have a direct link to this, it's a file i have saved on my hard drive very long time ago. but it should be available by a search.

national committee for aeronautics
technical note #674

title research paper: scavenging a piston ported two stroke cylinder

"......an improvement in scavenging efficiency of approximately 3% was realized by substituting a round top piston for a flat top piston."

(good info on intake and exhaust port angles in that paper).

using some on-line engine simulation calculators, i found that by plugging #'s in for a small displacement engine bore, stroke, rpm that an increase of 0.1 ft/lbs. of torque could be gained by raising compression.

hope it helps.


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## Terry Syd (Dec 19, 2011)

Are you sure it was #674? All I got with that number was a paper on air cooling (pretty good research in any case)


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## one.man.band (Dec 19, 2011)

research paper here:

Scavenging a piston-ported two-stroke cylinder : Rogowski, A R : Free Download & Streaming : Internet Archive


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## wyk (Dec 19, 2011)

Dennis Cahoon said:


> ......that's the trouble with dnyo's!......people Bull$hit you about how much hp they're making to sell their products.......064 with 20hp.....Hahahahahahaha!



Yup. I asked him how much it put on the dyno before he ported it, and he claimed a 044 or 440 did 5.1 hp. Still, it's just his word. Even piped and on meth, that seems pretty high.


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## RTK (Dec 19, 2011)

one.man.band said:


> sorry...don' have a direct link to this, it's a file i have saved on my hard drive very long time ago. but it should be available by a search.
> 
> national committee for aeronautics
> technical note #674
> ...





one.man.band said:


> research paper here:
> 
> Scavenging a piston-ported two-stroke cylinder : Rogowski, A R : Free Download & Streaming : Internet Archive



Looks like it depended a lot on port lay out and timing in that paper, or did I mis something


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## one.man.band (Dec 19, 2011)

cannot comment on intake flow over piston, but can say that flame front could suffer over very high domes.

gained 5 hp (with smoother idle and acceleration) on a originally 70 hp bike whose heads were bored for second plug. the domes on pistons were approximately 1" (w/valve pockets cut in).

the small diameter bore of a saw is less the than 1/2 than the motor i am talking mentioned, so in comparison most likely the flame travel issue would not be as evident, but still there.


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## tree monkey (Dec 19, 2011)

one.man.band said:


> research paper here:
> 
> Scavenging a piston-ported two-stroke cylinder : Rogowski, A R : Free Download & Streaming : Internet Archive



dated, november 1 1938


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## tree monkey (Dec 19, 2011)

Terry Syd said:


> Treemonkey, I think you are confusing Bell with Blair. Bell's work was rather simplified, he didn't even use time/area, only timing figures. Blair on the other hand is at the engineering level.
> 
> If you take a look at Blair's work you will find a reference to 'Loopsaw'. That is a chainsaw engine that he uses for comparative work. He even does some modification of Loopsaw in one of his chapters (towards the end I think). Whereas Jennings time/area is relevant to oversquare piped engines, chainsaws are a different animal. I was able to glean a real nugget of information from Blair's work for the time/area of transfers on chainsaws.
> 
> Timberwolf had stated that he found a time/area for transfers less than the bottom range of Jennings formulas and charts to work for chainsaws. When I found Blair's reference to chainsaw transfer time/area he confirmed what Timberwolf said with an actual number to work with - I won't ruin the surprise, you can find it with the link.



was thinking of jennings


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## tree monkey (Dec 19, 2011)

Andyshine77 said:


> Precisely how it works IMHO.



you don't want the fresh charge mixing with the old charge. you want the fresh charge to push out as mutch of the old charge as posable with a min amount of fresh charge lost out the ex port.


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## ncfarmboy (Dec 20, 2011)

There must be something with windows vs no windows the new Dolmar P&C's for the 5100/5105 and the 7900 no longer have windows. Don't know on the 7900 yet but the 5100 non windowed piston has wider skirts than the original windowed version.
Shep


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## AUSSIE1 (Dec 20, 2011)

Andyshine77 said:


> My experience is limited, that's why I wanted to hear from people with more experience.
> 
> One thing I don't like is jumping on the bandwagon and doing something that has zero proof it actually works. Windows in pistons that have cylinders with bottom feeding transfers, simply does not work. The only thing I can see the windows doing in these cylinders is forcing some charge back down the transfers, plus unwanted turbulence, just like EC said.
> 
> ...



Andy, the only way you'll have proof something works is to try it yourself. Bradley has said he's tried the windows and they work for him? Did he try the windows separate from "raising" the lowers? 

The experience I've had with windows was with the 064 piston that already had the windows (372BB). I started off with std level lowers to slowly raising them a little more each time with excellent results, so I can't say whether the windows had a positive or negative affect in this application. Some say they had negative results raising the lowers. Had they windowed pistons at the same time? 

175psi is a good figure for a work saw. I wouldn't sniff at that!

My 064 pistoned 371XP BB was running 205psi after many, many tanks through it which surprised me it ending up that high. That really had some balls that saw and I really gave that saw a decent pushing in big hardwood that was too big really for it's bottom end build strength. Next thing I know the saw is running a little sluggish, so I checked and it was down on compression. I flipped the lid and the piston had started to touch the squish band. A new piston, pin and small end brg and she is back together with a little less compression and an easier life.


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## parrisw (Dec 20, 2011)

What about saws like the 200T, its an open port saw and has a windowed piston. If windows were going to screw up transfer flow in a saw, you'd think it would really do it in a open port! But the 200T is a little gutsy saw.


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## blsnelling (Dec 21, 2011)

Most saws don't have 175 PSI stock, even with the squish tightened. A popup will often give you about 20 PSI. I feel it's well worth the effort to get in the 175-190 PSI ballpark.


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## Mastermind (Dec 21, 2011)

I like popups when adding compression is needed. I'm thinking of Wiggs 460 with 30psi less than mine and the same port timing....mine was quile a bit stronger. 

Like has been said though. There is a point where too much is reached and the engine goes backward. 

Windowed pistons in bottom feeding transfer jugs I ain't a fan of. I can't see doing anything to lose case pressure...


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## Dennis Cahoon (Dec 21, 2011)

blsnelling said:


> Most saws don't have 175 PSI stock, even with the squish tightened. A popup will often give you about 20 PSI. I feel it's well worth the effort to get in the 175-190 PSI ballpark.



If you only knew how to tighten-up the combustion chamber Brad!......Hahahahahaha!


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## parrisw (Dec 21, 2011)

Mastermind said:


> I like popups when adding compression is needed. I'm thinking of Wiggs 460 with 30psi less than mine and the same port timing....mine was quile a bit stronger.
> 
> Like has been said though. There is a point where too much is reached and the engine goes backward.
> 
> Windowed pistons in bottom feeding transfer jugs I ain't a fan of. I can't see doing anything to lose case pressure...



How does it loose case pressure? That little bit of material gone from the piston is going to change case pressure?


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## tree monkey (Dec 21, 2011)

parrisw said:


> How does it loose case pressure? That little bit of material gone from the piston is going to change case pressure?



it 's not going to change a thing in a work saw one way or the other. been there done that. the best thing i ever done was to stop playing with the tach and stopwatch. thay cant show torqe, you have to feel it.


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## Dennis Cahoon (Dec 21, 2011)

Never owned a tach!....what are they?.....something you eat!......Hahahahahahaha!


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## parrisw (Dec 21, 2011)

tree monkey said:


> it 's not going to change a thing in a work saw one way or the other. been there done that. the best thing i ever done was to stop playing with the tach and stopwatch. thay cant show torqe, you have to feel it.



Agreed about the tach, I have one, it lives most of the time in the bottom of the tool box.

Everyone's got an opinion, go with what ya feel.

All this talk about popups and windows. Makes me want to take out my windowed popup piston in my 372 and stick a stock on back in and see if there is any diff.


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## chainsaw kid (Dec 21, 2011)

parrisw said:


> Agreed about the tach, I have one, it lives most of the time in the bottom of the tool box.
> 
> Everyone's got an opinion, go with what ya feel.
> 
> All this talk about popups and windows. Makes me want to take out my windowed popup piston in my 372 and stick a stock on back in and see if there is any diff.



I'd be curious to see what you find out. When you going to do it/or do you have the time?


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## parrisw (Dec 21, 2011)

chainsaw kid said:


> I'd be curious to see what you find out. When you going to do it/or do you have the time?



I don't know when. I'm building a 390xp right now. I have a couple other saws which I was going to do next, but they could wait. It would take a bunch of work to put a stock piston back in, since its machined for a popup, for a stock piston to fit I'd need to setup for cutting the squish band on 372's, and it would change ex and transfer timing. I'm just setting up now to be able to cut squish bands, never attempted it before. Got a plate made on Monday for cutting 390's.


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## tree monkey (Dec 21, 2011)

chainsaw kid said:


> I'd be curious to see what you find out. When you going to do it/or do you have the time?



been there done that. i dont do popups unless i have no other choice


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## HEAVY FUEL (Dec 21, 2011)

tree monkey said:


> been there done that. i dont do popups unless i have no other choice



That popup in a stock 6400 was rather interesting.....


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## mweba (Dec 21, 2011)

Posting this for HEAVYFUEL.






Cause he asked nicely


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## HEAVY FUEL (Dec 21, 2011)

Thanks Mitch!!


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## chainsaw kid (Dec 21, 2011)

parrisw said:


> I don't know when. I'm building a 390xp right now. I have a couple other saws which I was going to do next, but they could wait. It would take a bunch of work to put a stock piston back in, since its machined for a popup, for a stock piston to fit I'd need to setup for cutting the squish band on 372's, and it would change ex and transfer timing. I'm just setting up now to be able to cut squish bands, never attempted it before. Got a plate made on Monday for cutting 390's.



I know how little time we all have with our busy lives.. just wasn't sure if it was one of those things you were chomping at the bit to do. I'd have a hard time myself pulling apart a saw that runs raped ape already. I'm assuming it's the one in your video, that saw goes nice (I'm sure you fattened it up though and she goes a bit better).


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## ECsaws (Dec 21, 2011)

parrisw said:


> Agreed about the tach, I have one, it lives most of the time in the bottom of the tool box.
> 
> Everyone's got an opinion, go with what ya feel.
> 
> All this talk about popups and windows. Makes me want to take out my windowed popup piston in my 372 and stick a stock on back in and see if there is any diff.



Will you maybe surprised how differnt your saw may act, I'm going to just guess it will idle better and spool up will be much smoother, especially if you set your saw down for a bit and leave it run when you pick it up most likely it wont be loaded up as much... anyhow thats what I have found...other than that no gains + or -with windowing a none windowed piston...


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## srcarr52 (Dec 21, 2011)

My TN build off 372 did not have a pop-up and I wished I would have done it, then maybe I would have placed higher. When I sent it out it was on still on it's first tank of fuel and it only had 140 psi, when I got it back it was up to 150. It did have a windowed piston and raised transfer lower like most of the others. Still it's warmed up a bit and became one great runner.


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## srcarr52 (Dec 21, 2011)

ECsaws said:


> Will you maybe surprised how differnt your saw may act, I'm going to just guess it will idle better and spool up will be much smoother, especially if you set your saw down for a bit and leave it run when you pick it up most likely it wont be loaded up as much... anyhow thats what I have found...other than that no gains + or -with windowing a none windowed piston...



I have a 371/372 cylinder for you. It had a lot of transfer so I cleaned it with acid but there still was a little pit above and to the left of the exhaust port. I always thought I would throw together a spare parts saw with it but for a little more then a good piston I could try a BB kit so I'll never use it. It's yours for cost of post.


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## parrisw (Dec 21, 2011)

chainsaw kid said:


> I know how little time we all have with our busy lives.. just wasn't sure if it was one of those things you were chomping at the bit to do. I'd have a hard time myself pulling apart a saw that runs raped ape already. I'm assuming it's the one in your video, that saw goes nice (I'm sure you fattened it up though and she goes a bit better).



Yes, espicially this time of year, and with two young kids 7 & 10, that takes away most of my time! I do really want to try it and I'm certain I will, but ya I do love that saw, runs great. Yes its the one in that video, that was its first outing and it really came alive after that vid I went straight down to the truck and richened up up nicely.



ECsaws said:


> Will you maybe surprised how differnt your saw may act, I'm going to just guess it will idle better and spool up will be much smoother, especially if you set your saw down for a bit and leave it run when you pick it up most likely it wont be loaded up as much... anyhow thats what I have found...other than that no gains + or -with windowing a none windowed piston...



Thanks Eric, I'm real curious to try it. I have noticed that before with saws with popups, this one seems to be much better though?? Don't know why though, but if it will be better then it is now, I'm pretty excited about that.

Will


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## Mastermind (Dec 21, 2011)

Dennis Cahoon said:


> If you only knew how to tighten-up the combustion chamber Brad!......Hahahahahaha!



I'm working on that myself Dennis. I've got a lot to learn........

It seem like when I think I've figured this stuff out something happens that makes me take another look at my theories..... :msp_unsure: 



parrisw said:


> How does it loose case pressure? That little bit of material gone from the piston is going to change case pressure?



I have a idea about why these type saws have a solid piston in the first place. It seems to me that as the piston makes it's way down in the cylinder it carries with it a "solid" area that increases the pumping action of the transfer ports. When you cut windows in the piston that area is larger and would have to decrease that action. 

At least in my mind I see it that way. :msp_confused:

I am in no way implying that I know anymore about this stuff that anyone else. These discussions are very important to me, and I thank everyone involved for their input. I enjoy learning all I can about these engines. :msp_thumbup:


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## komatsuvarna (Dec 21, 2011)

parrisw said:


> How does it loose case pressure? That little bit of material gone from the piston is going to change case pressure?



I think it will, but it will very little just opening up the windows some. Jmo.....


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## komatsuvarna (Dec 21, 2011)

I may be thinking about it wrong, but pressure is pressure right? Im comparing it to hydrostatic pressure testing. The higher the pressure, the less volume it takes to change it. The lower the pressure, the more volume it takes it takes to change it, but there isnt much volume in a crankcase anyways, and in my expierence about 5 psi +/-.


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## komatsuvarna (Dec 21, 2011)

Mastermind said:


> I'm working on that myself Dennis. I've got a lot to learn........
> 
> It seem like when I think I've figured this stuff out something happens that makes me take another look at my theories..... :msp_unsure:
> 
> ...



Never thought about it that way Randy, but i see exactly what your saying.

I like these discussions :smile2:


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## Jacob J. (Dec 21, 2011)

komatsuvarna said:


> I may be thinking about it wrong, but pressure is pressure right? Im comparing it to hydrostatic pressure testing. The higher the pressure, the less volume it takes to change it. The lower the pressure, the more volume it takes it takes to change it, but there isnt much volume in a crankcase anyways, and in my expierence about 5 psi +/-.



I think you're pretty much on the money. I guess the way I look at it is how the saw is designed initially to move fuel/air from the crankcase to the upper cylinder. I think the people having good luck with windowed pistons in saws like the 372 are doing so because they're turning that design into more of a through-transfer design and a less of a loop-transfer design. The same thing happened with the older Pioneer p series saws years ago. Guys would raise the bottom transfers and put small windows next to the wrist pin and gain around 1500-2k RPM.


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## srcarr52 (Dec 21, 2011)

Mastermind said:


> I'm working on that myself Dennis. I've got a lot to learn........
> 
> It seem like when I think I've figured this stuff out something happens that makes me take another look at my theories..... :msp_unsure:
> 
> ...



To further this topic.

Anytime you increase the volume of the crankcase with the piston at the just closing the intake port, you are decreasing you crankcase compression ratio which is key to getting the air fuel mixture pushed up the transfers. Also increasing your intake duration decreases the crankcase compression because there is less compression stroke inside the case. It's the trapped area vs. the area at BDC that creates the pressure needed to push the air/fuel up the transfers.

I know some older saws can really benefit from more crankcase compression (like a 272 or 288). I've had great results with filling in the crankcase in any area that I can with epoxy on these two saws. A. Bell also has a complete chapter on filling crankcases in his book, there is also another chapter on internally super charged engines which increase the crankcase compression even more but they were made illegal in racing in the 70's and the extra moving parts makes them not a great fit in smaller lightweight engines. So IMO crankcase compression is something to be concerned with.

And one more example is the Husky 357XP vs. the 359, same case and crank, but different cylinders and the 357 has inserts on the crank to make it full circle. You can put a 357 cylinder on a 359 but it will suck until you put the crank inserts in. 

I'd also like to see other options then cutting a pop-up, I've build mandrels to true up squish bands since the factory machine work there is often terrible. I don't see how I would chuck a whole cylinder in the lathe to get a boring bar in there to cut it, without over cutting and getting into the cylinder wall. 

I could see using the pulse mig or a tig welder with a long nozzle to fill in the combustion camber but then finishing it comes back to the above point.


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## Jacob J. (Dec 21, 2011)

srcarr52 said:


> And one more example is the Husky 357XP vs. the 359, same case and crank, but different cylinders and the 357 has inserts on the crank to make it full circle. You can put a 357 cylinder on a 359 but it will suck until you put the crank inserts in.



I actually had the opposite experience with a 357 top end on a 359 case. I ported the 357 cylinder the same way I had been doing the 372s (raising the lower transfer lip) and putting small (maybe tiny) windows in the piston and that turned out as a strong, strong saw. It would out-cut a stock 044 in the same wood and stay right with a stock 064 up to around 24" wood. I had smoothed out the squish band by hand and set the squish right at .020".


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## srcarr52 (Dec 21, 2011)

Jacob J. said:


> I actually had the opposite experience with a 357 top end on a 359 case. I ported the 357 cylinder the same way I had been doing the 372s (raising the lower transfer lip) and putting small (maybe tiny) windows in the piston and that turned out as a strong, strong saw. It would out-cut a stock 044 in the same wood and stay right with a stock 064 up to around 24" wood. I had smoothed out the squish band by hand and set the squish right at .020".



It probably would have ran better if you put the inserts in. I think the 357 top-end is much better then the 359 by design so I'm sure it ran great once you ported it.


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## Jacob J. (Dec 21, 2011)

srcarr52 said:


> It probably would have ran better if you put the inserts in. I think the 357 top-end is much better then the 359 by design so I'm sure it ran great once you ported it.



That was the interesting thing I found. I built two saws side by side. One 357 top on a 359 chassis, and one 357. Both had identical numbers, carburetors, and both were the same vintage. Both had brand new pistons. The regular 357 had great spool-up and acceleration but lacked torque, especially in bigger wood. The 359/357 hybrid would walk away from it in anything over 12-14".


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## srcarr52 (Dec 21, 2011)

Jacob J. said:


> That was the interesting thing I found. I built two saws side by side. One 357 top on a 359 chassis, and one 357. Both had identical numbers, carburetors, and both were the same vintage. Both had brand new pistons. The regular 357 had great spool-up and acceleration but lacked torque, especially in bigger wood. The 359/357 hybrid would walk away from it in anything over 12-14".



I think that coincidences with what was found out the the full circle crank in the 110B kart engines. If I remember the article correctly they made great short track engines but lacked the upper RPM horsepower. Probably because the flow in the transfers were getting too high in the upper RPM's with the full circle crank. As with anything... it's a balancing act.


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## Jacob J. (Dec 21, 2011)

srcarr52 said:


> I think that coincidences with what was found out the the full circle crank in the 110B kart engines. If I remember the article correctly they made great short track engines but lacked the upper RPM horsepower. Probably because the flow in the transfers were getting too high in the upper RPM's with the full circle crank. As with anything... it's a balancing act.



Plus I think it had a lot to do with the kind of numbers I was putting in the cylinders. I'd shortened the transfer ducts some and had kept the intake and exhaust ports low and wide. If I'd gone for more duration I think the crank stuffers would have made a difference.


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## Mastermind (Dec 21, 2011)

Jacob J. said:


> Plus I think it had a lot to do with the kind of numbers I was putting in the cylinders. I'd shortened the transfer ducts some and had kept the intake and exhaust ports low and wide. If I'd gone for more duration I think the crank stuffers would have made a difference.



I'm learning that on some saws short intake duration is a good thing. 

Like I keep saying..............the more I learn, the less I know. :hmm3grin2orange:


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## parrisw (Dec 21, 2011)

komatsuvarna said:


> I think it will, but it will very little just opening up the windows some. Jmo.....



I don't believe it will at all, look at the piston the sides are open, meaning there is a gap between the sides of the piston and cylinder wall, so the only area your loosing is the amount you cut out, lowering the cyl increase's case pressure, so that nulls out the amount you cut off the piston. To figure out case volume you stick the piston up in the cyl as far as it would go fill it with fluid and measure that amount, same with the crankcase.


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## komatsuvarna (Dec 21, 2011)

parrisw said:


> I don't believe it will at all, look at the piston the sides are open, meaning there is a gap between the sides of the piston and cylinder wall,* so the only area your loosing is the amount you cut out*, lowering the cyl increase's case pressure, so that nulls out the amount you cut off the piston. To figure out case volume you stick the piston up in the cyl as far as it would go fill it with fluid and measure that amount, same with the crankcase.



:smile2: I did say very little didn't I? :hmm3grin2orange:


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## srcarr52 (Dec 21, 2011)

parrisw said:


> I don't believe it will at all, look at the piston the sides are open, meaning there is a gap between the sides of the piston and cylinder wall, so the only area your loosing is the amount you cut out, lowering the cyl increase's case pressure, so that nulls out the amount you cut off the piston. To figure out case volume you stick the piston up in the cyl as far as it would go fill it with fluid and measure that amount, same with the crankcase.



Lowering the cylinder does not increase crankcase compression. You are interested in the trapped volume, so on a piston ported saw, so you'll measure the volume of the underside of the cylinder when the intake has just closed, a reed valve engine would be the whole cylinder.


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## AUSSIE1 (Dec 21, 2011)

BB's are a bigger pump.

Some bottom ends have run a range of different capacity top ends.


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## parrisw (Dec 21, 2011)

srcarr52 said:


> Lowering the cylinder does not increase crankcase compression. You are interested in the trapped volume, so on a piston ported saw, so you'll measure the volume of the underside of the cylinder when the intake has just closed, a reed valve engine would be the whole cylinder.



Ya, I guess that's correct. 

I still don't think widowns affect case compression at all.


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## srcarr52 (Dec 21, 2011)

parrisw said:


> Ya, I guess that's correct.
> 
> I still don't think widowns affect case compression at all.



Well, not a lot.


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## parrisw (Dec 21, 2011)

srcarr52 said:


> Well, not a lot.



LOL, theoretically ya it does, but how much? If you could measure it, it would be so minimal.


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## mt.stalker (Dec 21, 2011)

srcarr52 said:


> To further this topic.
> 
> Anytime you increase the volume of the crankcase with the piston at the just closing the intake port, you are decreasing you crankcase compression ratio which is key to getting the air fuel mixture pushed up the transfers. Also increasing your intake duration decreases the crankcase compression because there is less compression stroke inside the case. It's the trapped area vs. the area at BDC that creates the pressure needed to push the air/fuel up the transfers.
> 
> ...



This is so cool , reading these chats between you and Randy and Jacob and others too numerous to mention , your experiances . It is so interesting / educating to us rookies we can't thenk all of you enough . God i love this stuff .
Thanks again,
John


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## Andyshine77 (Dec 21, 2011)

parrisw said:


> Ya, I guess that's correct.
> 
> I still don't think widowns affect case compression at all.



I don't have the numbers to back it up, but two well respected saw builder told me just the opposite. On top of that the fastest 372's I've ran didn't have windowed pistons.. Again this is simply what I've been told, I think they're correct, but I'm not 100% sure of it. So far it looks like they may be right.


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## mdavlee (Dec 21, 2011)

I did the 2171 and 372 with popups. One got windows and the other didn't. The timing numbers were almost identical. I think the exhaust was 1° different and the blowdown and intake were the same. The one without windows was way stronger than the other one. Both were blowing around 200 lbs of compression.


----------



## Andyshine77 (Dec 21, 2011)

mdavlee said:


> I did the 2171 and 372 with popups. One got windows and the other didn't. The timing numbers were almost identical. I think the exhaust was 1° different and the blowdown and intake were the same. The one without windows was way stronger than the other one. Both were blowing around 200 lbs of compression.



Good deal. Pop ups really seem to work with the 372's, again I think it has to do with the transfer design.


----------



## mdavlee (Dec 21, 2011)

I would like to try one without a popup and cutting the chamber and see how it turns out with similar numbers. I know I won't put windows in a 372 piston and raise the lowers again.


----------



## parrisw (Dec 21, 2011)

Andyshine77 said:


> I don't have the numbers to back it up, but two well respected saw builder told me just the opposite. On top of that the fastest 372's I've ran didn't have windowed pistons.. Again this is simply what I've been told, I think they're correct, but I'm not 100% sure of it. So far it looks like they may be right.



Fair enough. But how does it affect base compression much at all? Yes it does cause your loosing that small bit of area from cutting the windows, but other then that there is no way it can affect base compression, if it does, then tell me how??? Not just because I said so. That's crap!!!!!!!!


----------



## parrisw (Dec 21, 2011)

mdavlee said:


> I would like to try one without a popup and cutting the chamber and see how it turns out with similar numbers. I know I won't put windows in a 372 piston and raise the lowers again.



I'm going to do this when I have time. I wish I had an endless supply of OEM jugs and time to play with. I'll need to order up another meteor piston, and setup for cutting 372 squish bands. I have another 372 jug to play with as well. I'd be worried about doing it on BB kits due to the lack of plating all the way up, really don't know how far you can go.


----------



## Jacob J. (Dec 21, 2011)

parrisw said:


> I'm going to do this when I have time. I wish I had an endless supply of OEM jugs and time to play with. I'll need to order up another meteor piston, and setup for cutting 372 squish bands. I have another 372 jug to play with as well. I'd be worried about doing it on BB kits due to the lack of plating all the way up, really don't know how far you can go.



I think I have an OEM jug or two that you can have for testing builds. I'll throw in some pistons and rings as well.


----------



## mdavlee (Dec 21, 2011)

I don't even have any form of 372 to try it out on. The only 70cc I have is the 576.


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## parrisw (Dec 21, 2011)

Jacob J. said:


> I think I have an OEM jug or two that you can have for testing builds. I'll throw in some pistons and rings as well.



:smile2:,

I have one Jug, and one well used oem piston that I'd rather not use.


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## Mastermind (Dec 21, 2011)

I have to try to picture this stuff in my head. A full skirt piston is carrying a load of air inside it...like a bucket. Cutting a window in that would let it leak out the side instead of it being directed into the lower transfer inlet. It seems like the sideways flow would hamper the upward flow into the transfer tunnel.

I'm sure this makes no sense at all to anyone...but I understand it.


----------



## WoodChuck'r (Dec 21, 2011)

Lotta good reading in this thread. 

Kudos to Andre for starting the conversation and as well to others for chootin' the chit on a good subject. 


This stuff is *way* outta my league but I'm definitely a big fan of talk like this. I've been watchin' this thread but I don't have much to add to any of what's bein' said. 

Good stuff though guys. Good stuff. Thanks for keepin' an ignorant fool like myself somewhat in the know. 


Keep it up d00dz. Keep it up. :msp_thumbup:


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## parrisw (Dec 21, 2011)

Mastermind said:


> I have to try to picture this stuff in my head. A full skirt piston is carrying a load of air inside it...like a bucket. Cutting a window in that would let it leak out the side instead of it being directed into the lower transfer inlet. It seems like the sideways flow would hamper the upward flow into the transfer tunnel.
> 
> I'm sure this makes no sense at all to anyone...but I understand it.



I see your thinking. But here is my thinking. Don't think of it as a bucket, I think of it as pushing air from the rings down, since the piston isn't a air tight seal on the jug. The parts of the piston from the rings down, just take up volume IMHO, but I could be wrong! LOL


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## Mastermind (Dec 21, 2011)

parrisw said:


> I see your thinking. But here is my thinking. Don't think of it as a bucket, I think of it as pushing air from the rings down, since the piston isn't a air tight seal on the jug. The parts of the piston from the rings down, just take up volume IMHO, but I could be wrong! LOL



The most important lesson I've ever learned is to realize I'm not as smart as the engineers that designed these engines. I stick to enhancing what is there rather than redesigning it.

There has to be a reason they didn't want a windowed piston in that jug in the first place.


----------



## parrisw (Dec 21, 2011)

Mastermind said:


> The most important lesson I've ever learned is to realize I'm not as smart as the engineers that designed these engines. I stick to enhancing what is there rather than redesigning it.
> 
> There has to be a reason they didn't want a windowed piston in that jug in the first place.



MEH, what the hell do they know anyway.


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## Mastermind (Dec 21, 2011)

parrisw said:


> MEH, what the hell do they know anyway.



:biggrin::biggrin::biggrin:


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## tree monkey (Dec 21, 2011)

the tenn gtg 372 yhat i did, did not have a popup or windows. i think it placed ok:biggrin:
if ported corectly, large case valume= torque, small case valume= rpm

so are we still talking about woods saws?:msp_tongue:


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## Andyshine77 (Dec 22, 2011)

Mastermind said:


> I have to try to picture this stuff in my head. A full skirt piston is carrying a load of air inside it...like a bucket. Cutting a window in that would let it leak out the side instead of it being directed into the lower transfer inlet. It seems like the sideways flow would hamper the upward flow into the transfer tunnel.
> 
> I'm sure this makes no sense at all to anyone...but I understand it.



Randy this is how I see it working in my mind, and by looking at the P&C. I would also think it creates unwanted turbulence. Every little bit likely counts I guess, some guys even deck the case for more base pressure.


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## Mastermind (Dec 22, 2011)

Andyshine77 said:


> Randy this is how I see it working in my mind, and by looking at the P&C. I would also think it creates unwanted turbulence. Every little bit likely counts I guess, some guys even deck the case for more base pressure.



I'll be building a 372XP for Stumpy in a few days (I have to catch up some first) that saw will be getting a popup piston with no windows and very little lower transfer hogging...err I mean work. 

It will be seeing quite a bit of upper transfer massage though.


----------



## parrisw (Dec 22, 2011)

Mastermind said:


> I'll be building a 372XP for Stumpy in a few days (I have to catch up some first) that saw will be getting a popup piston with no windows and very little lower transfer hogging...err I mean work.
> 
> It will be seeing quite a bit of upper transfer massage though.



Can't wait to see how it turns out Randy. On the lowers, I only do a case match and blend them in, as well as raise to the cyl base. I'm real curious to see how yours comes out.


----------



## parrisw (Dec 22, 2011)

I've been thinking again guys about going back into mine, and I'm not going to mess with the cylinder that's already on there, if I lower the cylinder more, the intake #'s will go up, and not sure I want that. So, I do have another stock OEM jug here that I can do and play around with cutting the squish band on that and don't put any windows in the piston, then I can put that on my other saw, and essentially have a 372 shootout between my two saws. Wont be able to do it right away, but soon hopefully, will have to put a couple other projects back a bit to do it.


----------



## tree monkey (Dec 22, 2011)

you have to know what your going to do before you start, three things i look at before i cut anything. 1, freeport 
2, intake 3, comp. what ever comea first is what i port it to.

i have cut the base on some saws as mutch as .080" without snaging the ring above the plating.


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## parrisw (Dec 22, 2011)

tree monkey said:


> you have to know what your going to do before you start, three things i look at before i cut anything. 1, freeport
> 2, intake 3, comp. what ever comea first is what i port it to.
> 
> i have cut the base on some saws as mutch as .080" without snaging the ring above the plating.



Yep, I know. 

Thinking again, which can be dangerous. It wouldn't effect intake timing if I stuck a stock piston back in and cut the squish band to get the correct squish, here I was thinking I'd have to drop the cylinder, but I wont. 

Anyway, I'm still gona leave this one alone and do up another cylinder so its easy to compare the two saws, with same port work but one with cut squish band and no windows.


----------



## Andyshine77 (Dec 22, 2011)

parrisw said:


> Yep, I know.
> 
> Thinking again, which can be dangerous. It wouldn't effect intake timing if I stuck a stock piston back in and cut the squish band to get the correct squish, here I was thinking I'd have to drop the cylinder, but I wont.
> 
> Anyway, I'm still gona leave this one alone and do up another cylinder so its easy to compare the two saws, with same port work but one with cut squish band and no windows.



Sounds like a plan, the results should be interesting.


----------



## parrisw (Dec 22, 2011)

Andyshine77 said:


> Sounds like a plan, the results should be interesting.



Ya, kinda excited about it. Going to have to wait till the new year though. But I'll be sure to let ya all know.


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## mdavlee (Dec 22, 2011)

tree monkey said:


> the tenn gtg 372 yhat i did, did not have a popup or windows. i think it placed ok:biggrin:
> if ported corectly, large case valume= torque, small case valume= rpm
> 
> so are we still talking about woods saws?:msp_tongue:



The one you did for that was the strongest I ran there.


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## srcarr52 (Dec 22, 2011)

Just a though, cutting the squish band would be the way to go on old 066's since they have a large amount of exhaust timing stock. That way you could real that back in or at least have room to make the port shape you want.

Can someone post a picture of their squish band cutting setup or write up how. I think I'll open back up my 372 to get the compression up.


----------



## Jacob J. (Dec 22, 2011)

srcarr52 said:


> Just a though, cutting the squish band would be the way to go on old 066's since they have a large amount of exhaust timing stock. That way you could real that back in or at least have room to make the port shape you want.
> 
> Can someone post a picture of their squish band cutting setup or write up how. I think I'll open back up my 372 to get the compression up.



Luckily the older 066s (Red Light era) have much more conservative timing than the poly-flywheel 066s and even more conservative numbers than the MS-660s with the cylinders made by Stihl. Cutting the squish band is the way to go in the newest saws for sure. If I remember correctly the duration I got on the last red-light saw I put a wheel on was around 160 and the last MS-660 was around 170.


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## srcarr52 (Dec 22, 2011)

Jacob J. said:


> Luckily the older 066s (Red Light era) have much more conservative timing than the poly-flywheel 066s and even more conservative numbers than the MS-660s with the cylinders made by Stihl. Cutting the squish band is the way to go in the newest saws for sure. If I remember correctly the duration I got on the last red-light saw I put a wheel on was around 160 and the last MS-660 was around 170.



I just did a poly flywheel 066 and I measured it at 167 on the exhaust and it had 28 deg of blowdown and only 154 intake. I shortened up the blowdown a bit and threw more intake timing at it to balance better with the exhaust timing. I only raised the exhaust 0.010" just to get it cleaned up and blended with the widening. I think it's a pretty good runner, we'll see how big of a smile it's owner has when he gets it back tomorrow.


----------



## Jacob J. (Dec 22, 2011)

srcarr52 said:


> I just did a poly flywheel 066 and I measured it at 167 on the exhaust and it had 28 deg of blowdown and only 154 intake. I shortened up the blowdown a bit and threw more intake timing at it to balance better with the exhaust timing. I only raised the exhaust 0.010" just to get it cleaned up and blended with the widening. I think it's a pretty good runner, we'll see how big of a smile it's owner has when he gets it back tomorrow.



I had a similar experience with the last 660 I did, it was a 2001 or so saw and still had a Mahle cylinder. The numbers were almost identical to yours but had a little less blowdown, around 24-25 duration, so I left that as is and brought the upper transfers around towards the intake. An early (late 80's) 064 I did once only had 20 degrees of blowdown and that one I left the lower transfers alone but really gave it a lot of upper transfer volume and that one turned out really good. It was a saw for my brother who was cutting logs at the time and he ran a 36" on it and it would hold 9500 in the cut in Port Orford cedar, which is fairly soft.


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## parrisw (Dec 22, 2011)

srcarr52 said:


> Just a though, cutting the squish band would be the way to go on old 066's since they have a large amount of exhaust timing stock. That way you could real that back in or at least have room to make the port shape you want.
> 
> Can someone post a picture of their squish band cutting setup or write up how. I think I'll open back up my 372 to get the compression up.



Look, back I posted my progress so far. Or go into Andy's 460 build thread, Eric and Dennis both posted how they do it, that's where I got my idea from.


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## srcarr52 (Dec 22, 2011)

Jacob J. said:


> I had a similar experience with the last 660 I did, it was a 2001 or so saw and still had a Mahle cylinder. The numbers were almost identical to yours but had a little less blowdown, around 24-25 duration, so I left that as is and brought the upper transfers around towards the intake. An early (late 80's) 064 I did once only had 20 degrees of blowdown and that one I left the lower transfers alone but really gave it a lot of upper transfer volume and that one turned out really good. It was a saw for my brother who was cutting logs at the time and he ran a 36" on it and it would hold 9500 in the cut in Port Orford cedar, which is fairly soft.



This one is going back to a logging operation and it will be wearing a 25" and an 8 pin. I told the guy for that size bar I wouldn't be lugging around a 90cc range saw, more like a 70cc range but he told me that there "ain't enough nut" in a 70cc and that he currently is using a 088 with that size bar. IMHO your powerhead shouldn't be longer than your bar but oh well I'm sure he'll be happy with the 066 and his back will be even more happy when I do a 460 for him.


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## ECsaws (Dec 22, 2011)

Mastermind said:


> I'll be building a 372XP for Stumpy in a few days (I have to catch up some first) that saw will be getting a popup piston with no windows and very little lower transfer hogging...err I mean work.
> 
> It will be seeing quite a bit of upper transfer massage though.



Seeing how its for stumpy if you wanna try a flat top send that cly to me and I will cut it for ya:smile2:


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## HEAVY FUEL (Dec 22, 2011)

srcarr52 said:


> Just a though, cutting the squish band would be the way to go on old 066's since they have a large amount of exhaust timing stock. That way you could real that back in or at least have room to make the port shape you want.
> 
> Can someone post a picture of their squish band cutting setup or write up how. I think I'll open back up my 372 to get the compression up.



That 064 I ran against you at the Iowa gtg, that top end was built by tree monkey on a 066 and I swapped it over to the 064. No popup just 288 piston.


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## Mastermind (Dec 22, 2011)

ECsaws said:


> Seeing how its for stumpy if you wanna try a flat top send that cly to me and I will cut it for ya:smile2:



I appreciate it Eric. To much shipping as it is though.


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## Dennis Cahoon (Dec 22, 2011)

No lathe Randy?.....how you doing your pop-ups?.....like Gypo, with a horse rasp......Hahahahahaha!


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## Mastermind (Dec 22, 2011)

Dennis Cahoon said:


> No lathe Randy?.....how you doing your pop-ups?.....like Gypo, with a horse rasp......Hahahahahaha!



I have a lathe, just haven't setup to cut the chamber yet. 

A good horse rasp is tough to beat though.


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## Hedgerow (Dec 22, 2011)

Mastermind said:


> I have a lathe, just haven't setup to cut the chamber yet.
> 
> A good horse rasp is tough to beat though.



And here I thought you were just gluing a quarter to the piston Randy???
ps:


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## wigglesworth (Dec 22, 2011)

Jacob J. said:


> ....If I remember correctly the duration I got on the last red-light saw I put a wheel on was around 160 and the last MS-660 was around 170.



Also, some of the early decomp cylinders had good timing numbers as well. I had one with 160/122/80. 

Too bad there's no way to tell an early decomp from a late one without a wheel....


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## parrisw (Dec 22, 2011)

Got a new OEM piston on the way for the 372 build. Windowless! Popupless! LOL


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## parrisw (Dec 22, 2011)

Dennis Cahoon said:


> No lathe Randy?.....how you doing your pop-ups?.....like Gypo, with a horse rasp......Hahahahahaha!



Carving knife I think.


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## rms61moparman (Dec 22, 2011)

I have been watching this thread with much interest.
All I know is, the hack that stuck my 372 together did a pretty good job!!!:hmm3grin2orange:

I am working on an 039 for the build-off and have a pop-up piston coming.
The compression is really low and I hope it will help.


Mike


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## Hedgerow (Dec 23, 2011)

rms61moparman said:


> I have been watching this thread with much interest.
> All I know is, the hack that stuck my 372 together did a pretty good job!!!:hmm3grin2orange:
> 
> I am working on an 039 for the build-off and have a pop-up piston coming.
> ...



How many pounds is it puffing right now?


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## blsnelling (Dec 23, 2011)

rms61moparman said:


> I have been watching this thread with much interest.
> All I know is, the hack that stuck my 372 together did a pretty good job!!!:hmm3grin2orange:
> 
> I am working on an 039 for the build-off and have a pop-up piston coming.
> ...



Doesn't your 372 have a popup?


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## rms61moparman (Dec 23, 2011)

Yes Brad,
My 372 does have a small pop-up.

The 039 is pulling 130 now with a new set of rings.


Mike


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## Mastermind (Dec 23, 2011)

I would like to thank everyone that has been a part of this thread. A more civil thread discussing differing opinions I can't recall.


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## Hedgerow (Dec 23, 2011)

rms61moparman said:


> Yes Brad,
> My 372 does have a small pop-up.
> 
> The 039 is pulling 130 now with a new set of rings.
> ...



Might be just what the DR ordered then... Machined? or welded?


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## rms61moparman (Dec 23, 2011)

Hedgerow said:


> Might be just what the DR ordered then... Machined? or welded?



Well I guess the answer to that would be...both!
Welded up then machined back down.


Mike


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## Hedgerow (Dec 23, 2011)

rms61moparman said:


> Well I guess the answer to that would be...both!
> Welded up then machined back down.
> 
> 
> Mike



That would be the answer I was looking for out of my non-well thought out question.
Thanks for interpreting it...
:big_smile:


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## ECsaws (Dec 23, 2011)

one for some discussion... Yes they do run well 6401 piston and cly..


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## pops21 (Dec 23, 2011)

This thread make me think of the old saying "you can skin a cat more the one way". I'm all ears and soaking up every bit of info. :msp_thumbup:


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## Hedgerow (Dec 23, 2011)

ECsaws said:


> one for some discussion... Yes they do run well 6401 piston and cly..



I dig my two Dolmar saws... But that port design is just funky... They're all aimed at the spark source... Closest are largest? Taking "open" to a new level???:msp_confused:


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## ECsaws (Dec 23, 2011)

Ok here are some pics of a 7900 piston and cylinder ..
Look hard but remember both motors work WELL on the same case !!!
Study them I think theres something to be learned :biggrin: Ive touched base with a few members on this before 













Whats the one BIG thing Dolmar is changing ????? these engineers aren't stupid


----------



## Jacob J. (Dec 23, 2011)

ECsaws said:


> Ok here are some pics of a 7900 piston and cylinder ..
> Look hard but remember both motors work WELL on the same case !!!
> Study them I think theres something to be learned :biggrin: Ive touched base with a few members on this before
> 
> Whats the one BIG thing Dolmar is changing ????? these engineers aren't stupid



Are they putting a slab-sided piston in the 6400 as well as the 7900?


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## ECsaws (Dec 23, 2011)

Jacob J. said:


> Are they putting a slab-sided piston in the 6400 as well as the 7900?



Yes same basic design
6400 is 47MM 7900 is 52MM


----------



## Hedgerow (Dec 23, 2011)

Jacob J. said:


> Are they putting a slab-sided piston in the 6400 as well as the 7900?



The piston is shorter in relation to the bore on the 7900... I'll have to look closer for a while to come up with anything else...:msp_confused:


----------



## ECsaws (Dec 23, 2011)

Hedgerow said:


> The piston is shorter in relation to the bore on the 7900... I'll have to look closer for a while to come up with anything else...:msp_confused:



the pin to crown height is the same .. skirts are the same the only real difference in design is the 7900 the windows on the intake side are a tad higher but thats not the point I'm trying to make.


----------



## parrisw (Dec 23, 2011)

ECsaws said:


> Ok here are some pics of a 7900 piston and cylinder ..
> Look hard but remember both motors work WELL on the same case !!!
> Study them I think theres something to be learned :biggrin: Ive touched base with a few members on this before
> 
> ...



So blowdown is longer with closed port? I never degreed my 6400, but the BB had allot of blowdown, and I never changed it. So the case compression is fairly high on these saws? They do have a pretty small case.


----------



## Jacob J. (Dec 23, 2011)

ECsaws said:


> the pin to crown height is the same .. skirts are the same the only real difference in design is the 7900 the windows on the intake side are a tad higher but thats not the point I'm trying to make.



It'd be interesting to see the data they compiled on the slab-sided piston vs. the windowed piston. Apparently something was good enough for
them to switch to the slab-sided.


----------



## ECsaws (Dec 23, 2011)

parrisw said:


> So blowdown is longer with closed port? I never degreed my 6400, but the BB had allot of blowdown, and I never changed it. So the case compression is fairly high on these saws? They do have a pretty small case.



I didnt wheel them to check timming... but I bet if I CC the case volume , then CC the cly volume i'd be willing to bet the ratio is real close to the same on both..( i will check to see) I check this ratio on every new model saw I play with good or bad.......this really comes into play with methanol when your trying to "force" 2 1/2 times the fuel through ....


----------



## steve316 (Dec 23, 2011)

*new 7900 piston*

the new 7900 piston that don't have windows; the side of the piston recesses in toward the center, like a formula 1 style piston also known as a box on box style piston, also currently used in nascar. they are lighter due to thiner skirt an sides but have shown to be just as reliable. Steve


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## komatsuvarna (Dec 23, 2011)

Looking at the lower transfers on the 7900, Looks like theyre designed to really blow the charge to intake side of the cylinder. It just looks like theyre angled more that way than some of the other quad port cylinders Ive seen.


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## Mastermind (Dec 23, 2011)

Them Dolmars are strange.......


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## parrisw (Dec 23, 2011)

ECsaws said:


> I didnt wheel them to check timming... but I bet if I CC the case volume , then CC the cly volume i'd be willing to bet the ratio is real close to the same on both..( i will check to see) I check this ratio on every new model saw I play with good or bad.......this really comes into play with methanol when your trying to "force" 2 1/2 times the fuel through ....



Looks like more transfer area on the 6400 as well, less velocity?


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## Bowtie (Dec 23, 2011)

Mastermind said:


> Them Dolmars are strange.......



But boy do they run like a striped assed ape. At least the 7900 I had did. I was stupid for letting that saw go...


----------



## Jacob J. (Dec 23, 2011)

Bowtie said:


> But boy do they run like a striped assed ape. At least the 7900 I had did. I was stupid for letting that saw go...



The only problem I had with mine was the filtration. I loved how it cut and I limped it along for about five months in the woods on a big-wood
thinning job. Eventually the crappy air filter got the better of me. I'm going to give it another try though.


----------



## Bowtie (Dec 23, 2011)

Jacob J. said:


> The only problem I had with mine was the filtration. I loved how it cut and I limped it along for about five months in the woods on a big-wood
> thinning job. Eventually the crappy air filter got the better of me. I'm going to give it another try though.



Did yours have the standard filter or HD filter?


----------



## Jacob J. (Dec 23, 2011)

Bowtie said:


> Did yours have the standard filter or HD filter?



Mine was the standard filter. This was before the HD filter system had come out. I sold it and then two months later 
Bailey's announced they were getting a new HD filter system for the 7900. That kinda burned me up. I'd had a custom
full-wrap handle made for mine and everything. 

This time I'm trying a Makita 7901 with the HD system and I think I've found a UNI cartridge that will fit the HD manifold.


----------



## Bowtie (Dec 23, 2011)

Jacob J. said:


> Mine was the standard filter. This was before the HD filter system had come out. I sold it and then two months later
> Bailey's announced they were getting a new HD filter system for the 7900. That kinda burned me up. I'd had a custom
> full-wrap handle made for mine and everything.
> 
> This time I'm trying a Makita 7901 with the HD system and I think I've found a UNI cartridge that will fit the HD manifold.



Wow, that sounds familiar.


----------



## parrisw (Dec 23, 2011)

I've got the HD setup on mine, and I can't say enough good things about it, its really great.


----------



## stihl038x2 (Dec 23, 2011)

Jacob J. said:


> Mine was the standard filter. This was before the HD filter system had come out. I sold it and then two months later
> Bailey's announced they were getting a new HD filter system for the 7900. That kinda burned me up. I'd had a custom
> full-wrap handle made for mine and everything.
> 
> This time I'm trying a Makita 7901 with the HD system and I think I've found a UNI cartridge that will fit the HD manifold.



Jacob, what is a "UNI" cartridge ? :msp_unsure:

Steve


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## parrisw (Dec 24, 2011)

Well boys, how did I do? First squish band machined. 390xp

I tell ya, much harder setup, then just machining a cylinder base.


----------



## Jacob J. (Dec 24, 2011)

Very cool Will...


----------



## parrisw (Dec 24, 2011)

Jacob J. said:


> Very cool Will...



Thanks!! 

I was a little worried about the first one, but all went well, I had the cylinder dialed exact at 0 runout, and a butted up the cutter to the squish band and took a very light cut and it was actually out of true by a couple of thou, but it looked like plating that made it out of true?? I don't know if some gets up on the squish band due to the plating process?? 

Forgot to add, I cut the squish band on a 2° taper up towards the center, don't know if it matters or not?


----------



## RiverRat2 (Dec 24, 2011)

parrisw said:


> Well boys, how did I do? First squish band machined. 390xp
> 
> I tell ya, much harder setup, then just machining a cylinder base.





You did it just like I was talkin/thinking about @ the shop yesterday!!!!

Really quite well actually!!! Good On ya!!!


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## rms61moparman (Dec 24, 2011)

You sure do nice work!!!


Mike


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## RiverRat2 (Dec 24, 2011)

parrisw said:


> Thanks!!
> 
> I was a little worried about the first one, but all went well, I had the cylinder dialed exact at 0 runout, and a butted up the cutter to the squish band and took a very light cut and it was actually out of true by a couple of thou, but it looked like plating that made it out of true?? I don't know if some gets up on the squish band due to the plating process??
> 
> Forgot to add, I cut the squish band on a 2° taper up towards the center, don't know if it matters or not?



That is a very good Idea will 2-4° is optimal for two smoke squish band taper... perfect,,,, you just saved me some time buddy,,,,

I just saved the pics and emailed them to the PC @ the shop,,, will buld my backing plate tomorrow and chuck up a wrecked cylinder to practice on!!!!


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## parrisw (Dec 24, 2011)

RiverRat2 said:


> You did it just like I was talkin/thinking about @ the shop yesterday!!!!
> 
> Really quite well actually!!! Good On ya!!!



Sweet! 



rms61moparman said:


> You sure do nice work!!!
> 
> 
> Mike



Thanks Mike.



RiverRat2 said:


> That is a good Idea 2-4° is optimal for two smoke squish bands is perfect,,,, you just saved me some time,,,,
> 
> I just saved the pics and emailed them to the PC @ the shop,,, will buld my backing plate tomorrow and chuck up a wrecked cylinder to practice on!!!!



Cool. I think Eric said somewhere he does 2° as well.


----------



## RiverRat2 (Dec 24, 2011)

ECsaws said:


> one for some discussion... Yes they do run well 6401 piston and cly..



Eric,,, that cylinder looks familiar,,, LOLOL,, It hasn't been run very much has it,,,,,


----------



## ECsaws (Dec 24, 2011)

parrisw said:


> Well boys, how did I do? First squish band machined. 390xp
> 
> I tell ya, much harder setup, then just machining a cylinder base.
> 
> [



LOl ya its not a 5 min job..
Looks good will ... Is that a small lip i see on the upper side ? cly must be cut round of your piston will drag @ TDC trust me I know .
Yes I do cut them on a 2* tapper ...


----------



## ECsaws (Dec 24, 2011)

RiverRat2 said:


> Eric,,, that cylinder looks familiar,,, LOLOL,, It hasn't been run very much has it,,,,,



I'd say not Rick.. the whole saw is very clean


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## Tzed250 (Dec 24, 2011)

ECsaws said:


> LOl ya its not a 5 min job..
> Looks good will ... Is that a small lip i see on the upper side ? cly must be cut round of your piston will drag @ TDC trust me I know .
> Yes I do cut them on a 2* tapper ...



+1

Did you check runout at the top of the bore? When dealing with a cylinder both ends must be concentric with the spindle. The term is coaxiality and it is difficult to obtain at times. 




Untitled by zweitakt250, on Flickr

On the gearbox pictured above there are the six bores that you can see through the sides of the case, as well as two coaxial bores in the end facing the spindle. The end facing the spindle is like a giant chainsaw cylinder in that it has a square flange with bolt holes in each corner. Setting this part up requires that when oriented to the spindle that each set of bores is coaxial to within .001", and that the split line of the case is level inside of .001". Takes about half a shift to make this happen. 

Notice the Monster can sitting on the corner of the table...


----------



## komatsuvarna (Dec 24, 2011)

Tzed250 said:


> +1
> 
> Did you check runout at the top of the bore? When dealing with a cylinder both ends must be concentric with the spindle. The term is coaxiality and it is difficult to obtain at times.
> 
> ...



What is that out of?!?!?! Got a picture of the engine it bolts to?:smile2:


----------



## stihl038x2 (Dec 24, 2011)

Tzed250 said:


> +1
> 
> Did you check runout at the top of the bore? When dealing with a cylinder both ends must be concentric with the spindle. The term is coaxiality and it is difficult to obtain at times.
> 
> ...



Those screw jacks make indicating it up a *bit* easier though !! When doing a jug I always get the feeling the flange is going to "let go", it's a challenge getting it tight enough not to move & not damaging things.

Steve


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## Tzed250 (Dec 24, 2011)

komatsuvarna said:


> What is that out of?!?!?! Got a picture of the engine it bolts to?:smile2:



It is the reduction gearbox from a longwall mining conveyor. A 700HP electric motor mounts to the end and the conveyor drive output is on the far left.


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## Mastermind (Dec 24, 2011)

Glad to see you giving it a try Will. The pic DC put up with a center pin in the top of the jug made good sense to me. The jug could be mounted on a centered mandrel then drilled for that pin with a tailstock mounted drill. The pin should then be centered with the bore and make set up much easier.

That of course is just me talking crap without having tried it though. :hmm3grin2orange:

Some of the work you guys post here is amazing. I've got a long way to go before I can do more than just very basic machine work.


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## parrisw (Dec 24, 2011)

ECsaws said:


> LOl ya its not a 5 min job..
> Looks good will ... Is that a small lip i see on the upper side ? cly must be cut round of your piston will drag @ TDC trust me I know .
> Yes I do cut them on a 2* tapper ...



Thanks for watching out Eric, I don't think its a lip, I think it just an illusion from the pic, from the light hitting it on an angle. I'll definitely be checking it very throughly though again.


----------



## wigglesworth (Dec 24, 2011)

Will, that looks good. 

I'd for sure be looking at that lip. Could just be an optical illusion though...


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## parrisw (Dec 24, 2011)

Ok it was late last night and guess I didn't look hard enough. There is a lip, but it's the same all the way around. So I didn't cut out far enough, hard to see in there while machining. So back on the lathe I go, now I wish I didn't take it off the lathe.


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## wigglesworth (Dec 24, 2011)

parrisw said:


> Ok it was late last night and guess I didn't look hard enough. There is a lip, but it's the same all the way around. So I didn't cut out far enough, hard to see in there while machining. So back on the lathe I go, now I wish I didn't take it off the lathe.



Ah man... Bummer. I've been there more than once. Pull something off the mill or the lathe, only to find out I had .010 more to go. Sucks Fo sho!!

Hopefully it won't take as long setting it up the second time.


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## parrisw (Dec 24, 2011)

wigglesworth said:


> Ah man... Bummer. I've been there more than once. Pull something off the mill or the lathe, only to find out I had .010 more to go. Sucks Fo sho!!
> 
> Hopefully it won't take as long setting it up the second time.



Ya not to worry though, at least I didn't go too far. Next time just have to make sure. I guess I was a little chicken about getting into the cyl wall.


----------



## Jacob J. (Dec 24, 2011)

parrisw said:


> Ya not to worry though, at least I didn't go too far. Next time just have to make sure. I guess I was a little chicken about getting into the cyl wall.



It's hard to think about ruining a $300 cylinder. :smile2:

The retired machinist that I was having do my pistons for a long time used to machine the giant rollers for the turbines
in a hydroelectric plant. These rollers were about 6' in diameter and about 30' long. I think he said they weighed around 40k lbs.
They had to be within 0.0002" or so otherwise they'd wobble and tear the whole works apart. If that happened it was
about $2.5 million fix.


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## ECsaws (Dec 24, 2011)

Will you need to set stops on your cross feed so you know your far enough and or not to far ....
Make sure your Base is square to if its not it wont be centered ..
This isn't as easy as most would think you change one thing and everything changes.
Before I got my new lathe I tried doing this on my little chinese one ... let just say it didn't work out to well couldn't hold it true and the tolerance just was to loose...


----------



## parrisw (Dec 24, 2011)

ECsaws said:


> Will you need to set stops on your cross feed so you know your far enough and or not to far ....
> Make sure your Base is square to if its not it wont be centered ..
> This isn't as easy as most would think you change one thing and everything changes.
> Before I got my new lathe I tried doing this on my little chinese one ... let just say it didn't work out to well couldn't hold it true and the tolerance just was to loose...



Right. I guess I should of started on a cheaper cylinder. I think it'll be fine though.


----------



## parrisw (Dec 24, 2011)

Jacob J. said:


> It's hard to think about ruining a $300 cylinder. :smile2:
> 
> .



Ya I don't want to ruin it that's for sure. There is only one way to learn though, that's to just do it. Can't be done isn't in my vocabulary.


----------



## Mastermind (Dec 24, 2011)

ECsaws said:


> Will you need to set stops on your cross feed so you know your far enough and or not to far ....
> Make sure your Base is square to if its not it wont be centered ..
> This isn't as easy as most would think you change one thing and everything changes.
> Before I got my new lathe I tried doing this on my little chinese one ... let just say it didn't work out to well couldn't hold it true and the tolerance just was to loose...



I'm still on the chinese lathe. It works well enough for popups after a ton of truing. I don't want to try cutting the squish band on it. 

I have a Craftsman Atlas coming from VA after the holidays.


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## parrisw (Dec 24, 2011)

Mastermind said:


> I'm still on the chinese lathe. It works well enough for popups after a ton of truing. I don't want to try cutting the squish band on it.
> 
> I have a Craftsman Atlas coming from VA after the holidays.



Mine is pretty accurate I think. It's an old cast iron Hercus. Just like an old South Bend.


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## ECsaws (Dec 24, 2011)

Will I get this close or I dont cut...
<iframe width="560" height="315" src="http://www.youtube.com/embed/NfVcm1rWdjs" frameborder="0" allowfullscreen></iframe>

You get yours straightened out ? It can be a real beach to set back up...


----------



## komatsuvarna (Dec 24, 2011)

This is a good thread, I just read it all again :smile2:.

I ordered a right angle handpiece setup the other day, and Im getting ready to go back in my 372 and do a little more upper transfer work now that I'll have the right tools to get in a quad port cylinder correctly.

As far as the upper transfer roofs, what angle do I need to be looking for? Do they need to be more flat like Mahle had them, or should they be angled up a couple degrees?


----------



## RiverRat2 (Dec 24, 2011)

komatsuvarna said:


> This is a good thread, I just read it all again :smile2:.
> 
> I ordered a right angle handpiece setup the other day, and Im getting ready to go back in my 372 and do a little more upper transfer work now that I'll have the right tools to get in a quad port cylinder correctly.
> 
> As far as the upper transfer roofs, what angle do I need to be looking for? Do they need to be more flat like Mahle had them, or should they be angled up a couple degrees?



Your right Durand,,,, this is an awesome thread!!! 

Merry Christmas,,,


----------



## RiverRat2 (Dec 24, 2011)

ECsaws said:


> Will I get this close or I dont cut...
> 
> You get yours straightened out ? It can be a real beach to set back up...



Ya, really hard to get it back in the same spot,,,,,

I have confidence that he Will!!! Give it his best,,,


----------



## parrisw (Dec 24, 2011)

ECsaws said:


> Will I get this close or I dont cut...
> <iframe width="560" height="315" src="http://www.youtube.com/embed/NfVcm1rWdjs" frameborder="0" allowfullscreen></iframe>
> 
> You get yours straightened out ? It can be a real beach to set back up...



ARRRGG no. I just spent and hour and 15 minutes trying to set it back up. Don't ask me how I got it square the first time??? Must of got lucky? I couldn't get it this time. I'm taking a break before I screw it up. How do you square your cyl up?


----------



## RiverRat2 (Dec 24, 2011)

parrisw said:


> ARRRGG no. I just spent and hour and 15 minutes trying to set it back up. Don't ask me how I got it square the first time??? Must of got lucky? I couldn't get it this time. I'm taking a break before I screw it up. How do you square your cyl up?



With a dial indicator and a small rawhide mallet what kind/type of indicator are you using???

Ohhh and practice makes "good enough",,, no such thing as perfect,,,

here is a decent one,,,http://www.ebay.com/itm/Dial-Indica...015?pt=LH_DefaultDomain_0&hash=item45ff8022c7


----------



## ECsaws (Dec 24, 2011)

parrisw said:


> ARRRGG no. I just spent and hour and 15 minutes trying to set it back up. Don't ask me how I got it square the first time??? Must of got lucky? I couldn't get it this time. I'm taking a break before I screw it up. How do you square your cyl up?



LOL go have a cold one and enjoy the evening come back to it in a couple days ...
I Just use a indicator and two chuck keys..... oh ya and some serious patients.... some times the biggest challenge is getting the base square.


----------



## Bowtie (Dec 24, 2011)

Great thread, and thank you Will for all the pics and info! also Merry christmas and good luck!!!


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## ECsaws (Dec 24, 2011)

parrisw said:


> Well boys, how did I do? First squish band machined. 390xp
> 
> I tell ya, much harder setup, then just machining a cylinder base.



One other thing I might "suggest" is use a "thicker block" so you can turn those jaws around on the chuck so you have more holding power...

Edit I just noticed maybe there not reversible ?


----------



## parrisw (Dec 24, 2011)

ECsaws said:


> LOL go have a cold one and enjoy the evening come back to it in a couple days ...
> I Just use a indicator and two chuck keys..... oh ya and some serious patients.... some times the biggest challenge is getting the base square.



Having a cold one right now! 

My problem is squaring the cylinder to the block, adjusting to 0 runout isn't a big deal, or to within .005". 

When you bolt up your cylinder to your block, how do you make sure its 100% square?

Yes the jaws are reversible.


----------



## parrisw (Dec 24, 2011)

RiverRat2 said:


> With a dial indicator and a small rawhide mallet what kind/type of indicator are you using???
> 
> Ohhh and practice makes "good enough",,, no such thing as perfect,,,
> 
> here is a decent one,,,Dial Indicator-Horizontal Brown & Sharpe-Best Test , 0.0001, Jeweled, Swiss made | eBay



Thanks. That's lilke what I'm using.


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## ECsaws (Dec 24, 2011)

parrisw said:


> Having a cold one right now!
> 
> My problem is squaring the cylinder to the block, adjusting to 0 runout isn't a big deal, or to within .005".
> 
> ...



By adjusting the thru bolts using a indicator.. Even if you cut the cly flat you still have to check it Ive neaver had one yet I didnt have to adjust.


----------



## Mastermind (Dec 24, 2011)

parrisw said:


> Having a cold one right now!
> 
> My problem is squaring the cylinder to the block, adjusting to 0 runout isn't a big deal, or to within .005".
> 
> ...



Can you mill a flat spot on the top of the jug Will?


----------



## parrisw (Dec 24, 2011)

ECsaws said:


> By adjusting the thru bolts using a indicator.. Even if you cut the cly flat you still have to check it Ive neaver had one yet I didnt have to adjust.



Maybe, I'm not thinking here. But where do you put the indicator to indicate square? I indicate the jug to 0 runout using the indicator in the middle of the bore, but then if I check somewhere else, its has some runout, so that means its not square.

I was thinking of mounting the indicator on the cross slide then run the indicator in and out of the bore to check for square.


----------



## parrisw (Dec 24, 2011)

Mastermind said:


> Can you mill a flat spot on the top of the jug Will?



no, I don't have a mill. I have a milling attachment for my lathe but its too small to hold a jug. 

It has a flat spot on the top, I should be able to adjust for square using the mounting bolts. But I just can't figure out how right now, I have no idea how I got it square last night?? LOL


----------



## ECsaws (Dec 24, 2011)

parrisw said:


> Maybe, I'm not thinking here. But where do you put the indicator to indicate square? I indicate the jug to 0 runout using the indicator in the middle of the bore, but then if I check somewhere else, its has some runout, so that means its not square.
> 
> I was thinking of mounting the indicator on the cross slide then run the indicator in and out of the bore to check for square.



"I" run a indicator flat aginst the base and adjust using the bolts sometimes the actual squish band will be uneven..
I have a deep reach indicator but its a real pain to use..


----------



## parrisw (Dec 24, 2011)

ECsaws said:


> "I" run a indicator flat aginst the base and adjust using the bolts sometimes the actual squish band will be uneven..
> I have a deep reach indicator but its a real pain to use..



AHHH, ok, so put the indicator on the flat base where the gasket would go. Sometimes its too simple to think about. LOL 

Many thanks for being patient with me Eric.


----------



## ECsaws (Dec 24, 2011)

parrisw said:


> AHHH, ok, so put the indicator on the flat base where the gasket would go. Sometimes its too simple to think about. LOL
> 
> Many thanks for being patient with me Eric.



LOL see I told ya a cold one would help ......
remember tho every time you make a change there is going to be a reaction other places...


----------



## Tzed250 (Dec 24, 2011)

ECsaws said:


> One other thing I might "suggest" is use a "thicker block" so you can turn those jaws around on the chuck so you have more holding power...
> 
> Edit I just noticed maybe there not reversible ?



It appears they are already reversed. 

When setting up for coaxiality it is best to use two dial indicators at the same time. One near the head and one near the base. Of course the one inside the cylinder must be small. This is a "best" method. Other methods will work but will take longer.


----------



## parrisw (Dec 24, 2011)

ECsaws said:


> LOL see I told ya a cold one would help ......
> remember tho every time you make a change there is going to be a reaction other places...



YEP! LOL. I don't know what I was or wasn't thinking!! LOL. Helps to sit down and think, ask a few questions, and usually the problem presents itself. Yep touch one, the other changes. Square it up first then set runout. Unfortunately this Christmas thing is going to slow me down for the next few days.



Tzed250 said:


> It appears they are already reversed.
> 
> When setting up for coaxiality it is best to use two dial indicators at the same time. One near the head and one near the base. Of course the one inside the cylinder must be small. This is a "best" method. Other methods will work but will take longer.



Yes they already are reversed John. I thought this way would be better, they sit nice and flat against the step in the jaws.


----------



## Andyshine77 (Dec 24, 2011)

ECsaws said:


> Ok here are some pics of a 7900 piston and cylinder ..
> Look hard but remember both motors work WELL on the same case !!!
> Study them I think theres something to be learned :biggrin: Ive touched base with a few members on this before
> 
> ...



Transfer volume looks reduced in the 7900 cylinder??

Here is a look at the new 7900 piston for those that haven't seen it. To me it looks lighter, yet just as strong.


----------



## stihl038x2 (Dec 24, 2011)

Your set-up looks ok to me Will. Just takes a lot of frustrating "tweeks" here & there.

Steve


----------



## stihl038x2 (Dec 24, 2011)

Andyshine77 said:


> Transfer volume looks reduced in the 7900 cylinder??
> 
> Here is a look at the new 7900 piston for those that haven't seen it. To me it looks lighter, yet just as strong.



Looks like the cross hatching (or checkering if you are a stock maker), in the mold was filed in by hand (not that it matters, just looks "cheap" to me).

Steve


----------



## Andyshine77 (Dec 24, 2011)

Will I'm sure you'll get it squared up. I know it's a lot of work, I've seen Nik work and you simply can't rush things when it comes to machine work..


----------



## blsnelling (Dec 24, 2011)

My 390XP cylinder's at Nik's shop now. I'm not sure when we'll be tackling it, but I'm sure it won't be a quick easy job.


----------



## Andyshine77 (Dec 24, 2011)

stihl038x2 said:


> Looks like the cross hatching (or checkering if you are a stock maker), in the mold was filed in by hand (not that it matters, just looks "cheap" to me).
> 
> Steve



Don't know. Mahle makes the piston so I'd guess it's a Mahle mold as well.


----------



## parrisw (Dec 25, 2011)

stihl038x2 said:


> Your set-up looks ok to me Will. Just takes a lot of frustrating "tweeks" here & there.
> 
> Steve






Andyshine77 said:


> Will I'm sure you'll get it squared up. I know it's a lot of work, I've seen Nik work and you simply can't rush things when it comes to machine work..



Yep thanks guys. Just had to step back and think about it, Eric has helped me allot on this, even the simple pointers really help. I'll get back to it, maybe tomorrow for a bit, I know what I have to do now. 



blsnelling said:


> My 390XP cylinder's at Nik's shop now. I'm not sure when we'll be tackling it, but I'm sure it won't be a quick easy job.



Cool, what's all getting done to it.


----------



## parrisw (Dec 25, 2011)

Andyshine77 said:


> Transfer volume looks reduced in the 7900 cylinder??



I thought the same thing, I think I mentioned it back a bit too.


----------



## Andyshine77 (Dec 25, 2011)

parrisw said:


> I thought the same thing, I think I mentioned it back a bit too.



I may have missed the post, this thread is going better than expected.:msp_thumbup:


----------



## parrisw (Dec 25, 2011)

ECsaws said:


> Ok here are some pics of a 7900 piston and cylinder ..
> Look hard but remember both motors work WELL on the same case !!!
> Study them I think theres something to be learned :biggrin: Ive touched base with a few members on this before
> 
> ...



Ok, just saw something, simple but yet hard to think of. I always wondered why those transfers were funny shape, look at it now, and I see they line up exactly with the piston skirts!! DUUUUU, so opening them up beyond that is redundant.


----------



## Andyshine77 (Dec 25, 2011)

parrisw said:


> Ok, just saw something, simple but yet hard to think of. I always wondered why those transfers were funny shape, look at it now, and I see they line up exactly with the piston skirts!! DUUUUU, so opening them up beyond that is redundant.



They run well stock for a reason.:smile2:


----------



## parrisw (Dec 25, 2011)

Andyshine77 said:


> They run well stock for a reason.:smile2:



Ya they do. I think I'd like to do another kit for my Makita, I think I can do a better job this time. Good thing it was a cheap BB kit, still runs well, I'm not unhappy with it at all, just think I can do better. Maybe a 7900 kit this time when I got some extra cash.


----------



## Andyshine77 (Dec 25, 2011)

parrisw said:


> Ya they do. I think I'd like to do another kit for my Makita, I think I can do a better job this time. Good thing it was a cheap BB kit, still runs well, I'm not unhappy with it at all, just think I can do better. Maybe a 7900 kit this time when I got some extra cash.



I have a BB kit I'm going to with play with, hopefully I can get it to run better than stock lol.


----------



## parrisw (Dec 25, 2011)

Andyshine77 said:


> I have a BB kit I'm going to with play with, hopefully I can get it to run better than stock lol.



LOL, I'm pretty sure mine runs better then stock. I could go back into it and play around some more, maybe I'll do that first.


----------



## ECsaws (Dec 25, 2011)

Andyshine77 said:


> Transfer volume looks reduced in the 7900 cylinder??
> 
> Here is a look at the new 7900 piston for those that haven't seen it. To me it looks lighter, yet just as strong.



Andy have you used that new piston yet ?
I may try to locate one and give it a whirl in the stumpy 7900 build. piston looks interesting to say the least...:wink2:


----------



## RiverRat2 (Dec 25, 2011)

parrisw said:


> I thought the same thing, I think I mentioned it back a bit too.



You did,,, and it got me to thinking,, but for right now,,, Hey it's Christmas!!!!

Merry Christmas everybody,,,!!!


----------



## parrisw (Dec 25, 2011)

Well, I got it done. Pretty happy and relieved now. Took me a farking hour to setup. This time I actually put a mandrel in the bore and pushed on that with the tailstock, then snugged up the bolts, that got it square to within 5 or 6 thou, then adjusted from there to 1/2thou, then set runout to 1/2thou, then went back and checked square, was within 1thou, so set that again, then set runout again to 1/2thou, and cut! Got some minor chatter marks this time at the outer edge of the bore, but it'll be fine, would speeding the lathe up help? Or beefer boring bar?

I know I've said this a million times now, but Thank you Eric for the help. And everyone else for a good positive thread.


----------



## ECsaws (Dec 25, 2011)

parrisw said:


> Well, I got it done. Pretty happy and relieved now. Took me a farking hour to setup. This time I actually put a mandrel in the bore and pushed on that with the tailstock, then snugged up the bolts, that got it square to within 5 or 6 thou, then adjusted from there to 1/2thou, then set runout to 1/2thou, then went back and checked square, was within 1thou, so set that again, then set runout again to 1/2thou, and cut! Got some minor chatter marks this time at the outer edge of the bore, but it'll be fine, would speeding the lathe up help? Or beefer boring bar?
> 
> I know I've said this a million times now, but Thank you Eric for the help. And everyone else for a good positive thread.



I'm no expert by any means will but my "guess " is the chatter is from the Bar, when you got out where the plating over laped the bore . I dont think it will be a issue but if it was me I would polish the piston to help deter detention
I did this one also while I was set up to do the 7900... its a 681 play saw. took a bit more LOL


----------



## wigglesworth (Dec 25, 2011)

Looks much better. 

Might be a bit "thick" in the edge. I'd check the squish real good out at the edge.


----------



## parrisw (Dec 25, 2011)

ECsaws said:


> I'm no expert by any means will but my "guess " is the chatter is from the Bar, when you got out where the plating over laped the bore . I dont think it will be a issue but if it was me I would polish the piston to help deter detention
> I did this one also while I was set up to do the 7900... its a 681 play saw. took a bit more LOL



Thanks Eric, ya I'm far from a professional, lol. The bar is kinda small and long, I could probably shorten it a little in the mount. But I think I'll get a bigger one. What do you use to polish pistons? Buffing wheel?

Wow you sure took allot out of that chamber! 

How far can you go before worrying about hanging a ring in above the plating?


----------



## wigglesworth (Dec 25, 2011)

ECsaws said:


> I'm no expert by any means will but my "guess " is the chatter is from the Bar, when you got out where the plating over laped the bore . I dont think it will be a issue but if it was me I would polish the piston to help deter detention
> I did this one also while I was set up to do the 7900... its a 681 play saw. took a bit more LOL



Wow. How much came out of that chamber? Looks like a bunch.


----------



## parrisw (Dec 25, 2011)

wigglesworth said:


> Looks much better.
> 
> Might be a bit "thick" in the edge. I'd check the squish real good out at the edge.



I looked at it real good before taking it off this time. I felt around with a real small screwdriver, there is no lip now, if anything I can feel the screwdriver hop off the plating.


----------



## Tzed250 (Dec 25, 2011)

parrisw said:


> Well, I got it done. Pretty happy and relieved now. Took me a farking hour to setup. This time I actually put a mandrel in the bore and pushed on that with the tailstock, then snugged up the bolts, that got it square to within 5 or 6 thou, then adjusted from there to 1/2thou, then set runout to 1/2thou, then went back and checked square, was within 1thou, so set that again, then set runout again to 1/2thou, and cut! Got some minor chatter marks this time at the outer edge of the bore, but it'll be fine, would speeding the lathe up help? Or beefer boring bar?
> 
> I know I've said this a million times now, but Thank you Eric for the help. And everyone else for a good positive thread.





ECsaws said:


> I'm no expert by any means will but my "guess " is the chatter is from the Bar, when you got out where the plating over laped the bore . I dont think it will be a issue but if it was me I would polish the piston to help deter detention
> I did this one also while I was set up to do the 7900... its a 681 play saw. took a bit more LOL





parrisw said:


> Thanks Eric, ya I'm far from a professional, lol. The bar is kinda small and long, I could probably shorten it a little in the mount. But I think I'll get a bigger one. What do you use to polish pistons? Buffing wheel?
> 
> Wow you sure took allot out of that chamber!
> 
> How far can you go before worrying about hanging a ring in above the plating?




Chatter is caused by a harmonic vibration between the tool and workpiece. More surface speed(more RPM) usually results in more chatter. The old adage for boring bars is fill the hole up. For a cylinder with a 2" bore then use a 1" bar. A steel boring bar should not extend more than 4 times its diameter beyond the tool holder, so a 3/4" bar should not extend more than 3" beyond the holder, or chatter is likely. Also, the greater the tool nose radius the greater the chance of chatter. If you encounter chatter the first step is to reduce spindle speed. 

This game called machining has many ins and outs..


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## parrisw (Dec 25, 2011)

I had the lathe spinning as slow as it would go.


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## Tzed250 (Dec 25, 2011)

parrisw said:


> I had the lathe spinning as slow as it would go.



What was the boring bar diameter? How far was it stuck out? What was the spindle speed?


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## tree monkey (Dec 25, 2011)

all this is cool , and fun. but i made hand tools that will do the same thing in about 15 min with no setup time.


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## parrisw (Dec 25, 2011)

Tzed250 said:


> What was the boring bar diameter? How far was it stuck out? What was the spindle speed?



I'll have to measure it. I posted a pic a little further back of it, take a look. I honestly can't remember the speed on slowest, I got it written down somewhere. 

I don't think I could even hold a 1" boring bar with my tool post.


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## parrisw (Dec 25, 2011)

tree monkey said:


> all this is cool , and fun. but i made hand tools that will do the same thing in about 15 min with no setup time.



Great! Care to share?


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## parrisw (Dec 25, 2011)

Tzed250 said:


> What was the boring bar diameter? How far was it stuck out? What was the spindle speed?



Here it is. I can go measure if ya want.


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## Tzed250 (Dec 25, 2011)

That bar is to small to be hung out that far. A 3/4" bar should be ok if you stay choked up on it. Measure the distance base to head then hang the bar .1" longer. Should be OK.


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## parrisw (Dec 25, 2011)

Tzed250 said:


> That bar is to small to be hung out that far. A 3/4" bar should be ok if you stay choked up on it. Measure the distance base to head then hang the bar .1" longer. Should be OK.



Unless I get a completely different tool post holder, I don't think I can hold 3/4" I think 5/8" max.


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## parrisw (Dec 25, 2011)

Actually, just remembered, I do have a heavy duty boring bar holder. I've never used it, will have to find out what size it can hold, then order a bar to fit that.


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## Tzed250 (Dec 25, 2011)

tree monkey said:


> all this is cool , and fun. but i made hand tools that will do the same thing in about 15 min with no setup time.



So have I ...




mandrel 2 by zweitakt250, on Flickr


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## parrisw (Dec 25, 2011)

Tzed250 said:


> So have I ...
> 
> 
> 
> ...



Do you ever have to worry about damaging the bore spinning that in there?

And is that very practical for actually removing a bunch of material? Like .030" or just making it even.


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## komatsuvarna (Dec 25, 2011)

Tzed250 said:


> So have I ...
> 
> 
> 
> ...



Ive thought about this, But it looks like it would be hard to get the area where the chamber meets the cylinder (in the corner) good enough to run a piston up in it. Maybe to clean it up some, But trying to cut .020-.030 , Id be iffy.....but Ive never tried it either......


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## Tzed250 (Dec 25, 2011)

parrisw said:


> Do you ever have to worry about damaging the bore spinning that in there?
> 
> And is that very practical for actually removing a bunch of material? Like .030" or just making it even.



Actually I did put a scratch in the bore with it because I didn't clean the swarf out often enough. Luckily it didn't affect compression. The tool isn't for removing a lot of material. You could take out .03 with it but it would take a while. I made it to true the squish band and for that it worked great.


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## parrisw (Dec 25, 2011)

Tzed250 said:


> Actually I did put a scratch in the bore with it because I didn't clean the swarf out often enough. Luckily it didn't affect compression. The tool isn't for removing a lot of material. You could take out .03 with it but it would take a while. I made it to true the squish band and for that it worked great.



Thanks, that's what I thought.


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## Tzed250 (Dec 25, 2011)

Here is a shot of the trued squish band. 

Flickr"><img src="http://farm2.static.flickr.com/1095/5161656020_421ee6e112_b.jpg" width="922"height="576" alt="squish 1" /></a>


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## tlandrum (Dec 25, 2011)

i have been using a mandrel to cut the combustion chamber flat for a long time and you CAN get all the way over to the edge. i use the grey plastic for a mandrel and it will not hurt the cylinder. why is so many people that have been using the pop up piston successfully for so many years all the sudden decided thats not the way to go any more. ive seen some really good running saws with pop ups. are these saws with the cut combustion chamber going to be that much different. are you going to feel it or is it something that will have to be seen by stop watch.i think on a woods ported saw there is not going to be enough difference to shake a stick at.just my opinion


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## parrisw (Dec 25, 2011)

tlandrum2002 said:


> i have been using a mandrel to cut the combustion chamber flat for a long time and you CAN get all the way over to the edge. i use the grey plastic for a mandrel and it will not hurt the cylinder. why is so many people that have been using the pop up piston successfully for so many years all the sudden decided thats not the way to go any more. ive seen some really good running saws with pop ups. are these saws with the cut combustion chamber going to be that much different. are you going to feel it or is it something that will have to be seen by stop watch.i think on a woods ported saw there is not going to be enough difference to shake a stick at.just my opinion



I haven't given up on it at all. Just something new for me to try, and if it works well, then I'm all for it.

Soon I'll be doing a 372 with cut combustion chamber to go head to head with my ported pop-up 372.


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## Mastermind (Dec 25, 2011)

Using the mandrel to aid in the setup was a great idea. I've been doing a lot of thinking on this setup. Having a centered mandrel in the chuck then sliding the jug over it and using a tailstock mounted drill to cut a centering pin in the top would give you a upper center. Then use that pin in a centered hole in the plate mounted in the chuck. Slide the mandrel in the bore and use the tail stock to hold that with a center while you snug the bolts. With any luck it should be real close when you pull the mandrel out.

Does this make any sense?


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## ECsaws (Dec 25, 2011)

Tzed250 said:


> So have I ...
> 
> 
> 
> ...



John you think you can cut .050 @ 2* and still keep semantically with that set up ?


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## parrisw (Dec 25, 2011)

Mastermind said:


> Using the mandrel to aid in the setup was a great idea. I've been doing a lot of thinking on this setup. Having a centered mandrel in the chuck then sliding the jug over it and using a tailstock mounted drill to cut a centering pin in the top would give you a upper center. Then use that pin in a centered hole in the plate mounted in the chuck. Slide the mandrel in the bore and use the tail stock to hold that with a center while you snug the bolts. With any luck it should be real close when you pull the mandrel out.
> 
> Does this make any sense?



Yes that makes perfect sense to me Randy. Though, I don't think the centering pin will help setup time anymore then what I did, you'll still have to square it up after, therefore I'd chose to not go through the hassle of more setup if it doesn't help. You really need to be dead on with this cutting the CC as I found out the hard way, good thing I didn't ruin a $$$$$ cylinder.


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## parrisw (Dec 25, 2011)

ECsaws said:


> John you think you can cut .050 @ 2* and still keep semantically with that set up ?



I was wondering how even it would be after sticking sandpaper on it, then the paper would wear out. And then how even could you cut the taper?


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## ECsaws (Dec 25, 2011)

tlandrum2002 said:


> i have been using a mandrel to cut the combustion chamber flat for a long time and you CAN get all the way over to the edge. i use the grey plastic for a mandrel and it will not hurt the cylinder. why is so many people that have been using the pop up piston successfully for so many years all the sudden decided thats not the way to go any more. ive seen some really good running saws with pop ups. are these saws with the cut combustion chamber going to be that much different. are you going to feel it or is it something that will have to be seen by stop watch.i think on a woods ported saw there is not going to be enough difference to shake a stick at.just my opinion



Terry the burn is a whole lot more efficient ... Plus when you wear out the piston sure is nice to just swap pistons and not have to cut a pop-up,
not so bad for some one set up,,,,, but for the average Joe faller it a BIG plus....


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## parrisw (Dec 25, 2011)

ECsaws said:


> Terry the burn is a whole lot more efficient ... Plus when you wear out the piston sure is nice to just swap pistons and not have to cut a pop-up,
> not so bad for some one set up,,,,, but for the average Joe faller it a BIG plus....



Cool. That's a big plus for me too about not having to cut a popup again, I have a few saws I've built with popups that run in a tree service 5 days a week, if one goes down would be real nice to just be able to slide in a new piston. And ya they are hard on the saws.


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## tlandrum (Dec 25, 2011)

the chamber would be what ever shape your mandrel is. keep fresh paper on it and it will cut fast and even. this stuff doesnt have to be over engineered to get the job done. im not saying that the boring bar is not more precise or yada yada yada but the job can be done with more simple tools if you take you time you could cut as deep as you want. i cut the cumbustion chamber just to make it flat and even out the squish band. i can cut a pop up piston in less than 5 minutes from out of the box the ready for the saw.


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## tree monkey (Dec 25, 2011)

View attachment 213355

this is a cut and finished squish band
View attachment 213357

this is a older 044 cylinder. i cut 1 turn with my hand cutter.


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## Tzed250 (Dec 25, 2011)

ECsaws said:


> John you think you can cut .050 @ 2* and still keep semantically with that set up ?



.05? I wouldn't even try. Anything over .015 and I'm going to setup a turning operation. 



parrisw said:


> I was wondering how even it would be after sticking sandpaper on it, then the paper would wear out. And then how even could you cut the taper?



The taper is cut on the face of the mandrel. 



tlandrum2002 said:


> the chamber would be what ever shape your mandrel is. keep fresh paper on it and it will cut fast and even. this stuff doesnt have to be over engineered to get the job done. im not saying that the boring bar is not more precise or yada yada yada but the job can be done with more simple tools if you take you time you could cut as deep as you want. i cut the cumbustion chamber just to make it flat and even out the squish band. i can cut a pop up piston in less than 5 minutes from out of the box the ready for the saw.




I agree. For light trueing the mandrel is a quick and efficient way, assuming you will do a few of the same cylinder. If I'm going after a compression change it is going to get chucked.


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## parrisw (Dec 25, 2011)

tree monkey said:


> View attachment 213355
> 
> this is a cut and finished squish band
> View attachment 213357
> ...



Looks nice. If ya don't mind showing, what does your cutter look like.


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## tree monkey (Dec 25, 2011)

i finish with the sand paper on mandral thing. but i cut with a cutter in my hands.


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## komatsuvarna (Dec 25, 2011)

tree monkey said:


> i finish with the sand paper on mandral thing. but i cut with a cutter in my hands.



You got any pictures of your cutter setup Scott?:smile2:


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## tree monkey (Dec 25, 2011)

for some reason i cant get any pics of my custom tools:msp_rolleyes:


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## Tzed250 (Dec 25, 2011)

tree monkey said:


> for some reason i *won't show* any pics of my custom tools:msp_rolleyes:



Fixed it for ya...


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## parrisw (Dec 26, 2011)

tree monkey said:


> all this is cool , and fun. but i made hand tools that will do the same thing in about 15 min with no setup time.





tree monkey said:


> for some reason i cant get any pics of my custom tools:msp_rolleyes:




Fair enough. But they why say anything in the first place? You just sound like a braggart.


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## tree monkey (Dec 26, 2011)

to make you think. i showed how to cut the base using a mandral 10 years ago. at the time every one was using a mill to do it. ive been cutting the squish for 8 years. i spend many hours looking for ways to do the task at hand faster and easier. 

there is always a sence of pride when you figure it out for yourself.


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## parrisw (Dec 26, 2011)

tree monkey said:


> to make you think. i showed how to cut the base using a mandral 10 years ago. at the time every one was using a mill to do it. ive been cutting the squish for 8 years. i spend many hours looking for ways to do the task at hand faster and easier.
> 
> there is always a sence of pride when you figure it out for yourself.



Yay for you, and there was probably someone doing it before you. Did you invent sliced bread as well?

All I'm saying is. You come on here saying how great you are, I can do it faster and better then anyone, then wont show anything. If everyone was like you there would be no forum. This is what forums are for. If you wish to show nothing, then don't. Just don't come out saying you can do it better, keep it to yourself. Just my opinion.

Sure it feels good to figure out something for yourself. So how did you ever learn anything? Did you ever have a teacher? Did anyone ever show you anything throughout your life? Most likely someone did.


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## tree monkey (Dec 26, 2011)

i did not say i could do anything better. only that there is a faster way.

if you went to a saw race and won every race, would you stand there and tell everyone everything you did to that saw in detail?

why should i?


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## parrisw (Dec 26, 2011)

tree monkey said:


> i did not say i could do anything better. only that there is a faster way.
> 
> if you went to a saw race and won every race, would you stand there and tell everyone everything you did to that saw in detail?
> 
> why should i?



You're not getting my point.

My point wasn't that you should show everyone your secrets. Just the way you came across about it, that's all. 

Maybe I over reacted. I apologize if I did.


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## Tzed250 (Dec 26, 2011)

parrisw said:


> Fair enough. But they why say anything in the first place? You just sound like a braggart.





tree monkey said:


> to make you think. i showed how to cut the base using a mandral 10 years ago. at the time every one was using a mill to do it. ive been cutting the squish for 8 years. i spend many hours looking for ways to do the task at hand faster and easier.
> 
> there is always a sence of pride when you figure it out for yourself.



In case you hadn't noticed, this thread is chock full of professional machinists sharing their knowledge. A bit of a stretch to believe you are holding on to some sort of proprietary methods about machining. 

I cut metal 9 hours a day, six days a week. I work with people that hide what they do because they think it is job security. They are looked at as jerks. I cut metal alongside others that will show anybody anything. They are called co-workers. 

Nobody said you shouldn't try to make a buck, but if that is your only goal other than to say look at me and what I can do then this thread isn't the place for you. 


parrisw said:


> Yay for you, and there was probably someone doing it before you. Did you invent sliced bread as well?
> 
> All I'm saying is. You come on here saying how great you are, I can do it faster and better then anyone, then wont show anything. If everyone was like you there would be no forum. This is what forums are for. If you wish to show nothing, then don't. Just don't come out saying you can do it better, keep it to yourself. Just my opinion.
> 
> Sure it feels good to figure out something for yourself. So how did you ever learn anything? Did you ever have a teacher? Did anyone ever show you anything throughout your life? Most likely someone did.



Well put. 



tree monkey said:


> i did not say i could do anything better. only that there is a faster way.
> 
> if you went to a saw race and won every race, would you stand there and tell everyone everything you did to that saw in detail?
> 
> why should i?



This thread ain't a race. It is a discourse about the pros and cons of piston modification. If your methods are so top secret then just keep the whole mess to yourself, or maybe start your own thread. 



parrisw said:


> You're not getting my point.
> 
> My point wasn't that you should show everyone your secrets. Just the way you came across about it, that's all.
> 
> Maybe I over reacted. I apologize if I did.



Over reaction? Not so much...


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## ECsaws (Dec 26, 2011)

Andyshine77 said:


> this thread is going better than expected.:msp_thumbup:



As the world turns,, to good to be true?? , Nice thread Andy lots of thoughts "shared" and some "great" ideas.


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## Mastermind (Dec 26, 2011)

Tzed250 said:


> In case you hadn't noticed, *this thread is chock full of professional machinists sharing their knowledge*. A bit of a stretch to believe you are holding on to some sort of proprietary methods about machining.
> 
> I cut metal 9 hours a day, six days a week. I work with people that hide what they do because they think it is job security. They are looked at as jerks. I cut metal alongside others that will show anybody anything. They are called co-workers.
> 
> ...




I'm in the wrong place. :hmm3grin2orange:

Good morning guys.


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## steve316 (Dec 26, 2011)

*telling how*

This is how people are,I draged raced for over 40 years , other racers would ask what cam, rocker arm ratio, compresion, timeing and a lot of other questions.I always tried to help buy telling what I had done. Most of the time they would do things different or have different results, or inprove on what I had done and share there results and help both of us. I was thinking everyone is like this ;I guess not.:msp_confused:steve


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## porsche965 (Dec 26, 2011)

Good thread. Subscribed.


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## Mastermind (Dec 26, 2011)

steve316 said:


> This is how people are,I draged raced for over 40 years , other racers would ask what cam, rocker arm ratio, compresion, timeing and a lot of other questions.I always tried to help buy telling what I had done. Most of the time they would do things different or have different results, or inprove on what I had done and share there results and help both of us. I was thinking everyone is like this ;I guess not.:msp_confused:steve




Drag racing is what started me on the quest for more power as well. I ended up giving up racing to be able to afford to build a house.....I just never started back.

I found AS in a google search while attempting to fix a mashed 028 I killed. I never heard anything about modifying a chainsaw until then. The way most members here shared information was refreshing compared to other forums I had visited. (I play chess online....talk about a group of pricks :msp_sneaky


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## srcarr52 (Dec 26, 2011)

tree monkey said:


> for some reason i cant get any pics of my custom tools:msp_rolleyes:



My original thought for cutting squish bands was to mill a place for a cutter into the mandrel I use to cut the bases and then turn it by hand but that would be a PITA to mill a spot in cutter into each mandrel. So my second thought was to make something like a ridge reamer except it cuts with the bore. That way it's adjustable and I don't have to make one to fit each bore. My guess is he's made something like the later but for one or two squish bands I think the lathe setup is the way to go. 

I also agree with mastermind, a center locating pin in the head would help with the lathe setup plus it would aid in holding the cylinder more securely.


----------



## RiverRat2 (Dec 26, 2011)

tree monkey said:


> i did not say i could do anything better. only that there is a faster way.
> 
> if you went to a saw race and won every race, would you stand there and tell everyone everything you did to that saw in detail?
> 
> why should i?





parrisw said:


> Fair enough. But they why say anything in the first place? You just sound like a braggart.




Cmon Fellas,,,, Can't we just all get along??? where's the Christmas Spirit??? we arent racing right now!!!!!!

Chill Out!!!!


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## mdavlee (Dec 26, 2011)

I thought about a tool similar as the bhj tooling rig that will cut orings in cylinder heads and blocks. It would just be on a lot smaller scale and have to mount in the bore.


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## parrisw (Dec 26, 2011)

Tzed250 said:


> In case you hadn't noticed, this thread is chock full of professional machinists sharing their knowledge. A bit of a stretch to believe you are holding on to some sort of proprietary methods about machining.
> 
> I cut metal 9 hours a day, six days a week. I work with people that hide what they do because they think it is job security. They are looked at as jerks. I cut metal alongside others that will show anybody anything. They are called co-workers.
> 
> ...



Thanks John, well put as well. 

Last thing I want to do is derail this thread, its been really great and informative thus far, so lets keep it going. 

I agree about teaching people as well. I'm an auto mechanic, and we have these things called apprentice's, and ya I try to show them everything I can. Do I worry about them taking my job after I've given them my knowledge? No, nothing takes the place of the amount of experience I have.

Anyway, back on track here.

Hope everyone had a good Christmas.


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## Tzed250 (Dec 26, 2011)

It would be nice to see a flat top vs. pop up shoot out. I have s waking feeling Eric may have already done one for himself...


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## parrisw (Dec 26, 2011)

Tzed250 said:


> It would be nice to see a flat top vs. pop up shoot out. I have s waking feeling Eric may have already done one for himself...



I will be doing one soon, with 372's. Hopefully do it in the new year.


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## FATGUY (Dec 26, 2011)

John, spot on! When I first began learning my trade (and I'm still learning to this day) there were guys who would try and cover the controler when they knew someone was watching and hoping to learn something. Guys like that are so insecure in their own abilities that they feel they have to hold on tooth and nail to what little knowledge they have. Othe guys would spend hours showing you anything you cared to learn. It occured to me some years later after I surpassed their abilities that they were hiding what they were doing because they were unsure of themselves. I for one have learned so much on this site that I am more than happy to share any bit of machining knowledge I have. I once heard a saying that went something like "Knowledge is something you can give away without losing anything."


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## Tzed250 (Dec 26, 2011)

FATGUY said:


> John, spot on! When I first began learning my trade (and I'm still learning to this day) there were guys who would try and cover the controler when they knew someone was watching and hoping to learn something. Guys like that are so insecure in their own abilities that they feel they have to hold on tooth and nail to what little knowledge they have. Othe guys would spend hours showing you anything you cared to learn. It occured to me some years later after I surpassed their abilities that they were hiding what they were doing because they were unsure of themselves. I for one have learned so much on this site that I am more than happy to share any bit of machining knowledge I have. I once heard a saying that went something like "Knowledge is something you can give away without losing anything."



All very true. Don't forget, you can learn something from the lowest guy in the shop. Everyone's experience counts. The lord gave us two ears, two eyes and one mouth for a reason.


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## stihl038x2 (Dec 26, 2011)

tree monkey said:


> i did not say i could do anything better. only that there is a faster way.
> 
> *if you went to a saw race and won every race, would you stand there and tell everyone everything you did to that saw in detail?*
> why should i?


Yep ! I probably would !! 

Steve


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## tree monkey (Dec 27, 2011)

srcarr52 said:


> My original thought for cutting squish bands was to mill a place for a cutter into the mandrel I use to cut the bases and then turn it by hand but that would be a PITA to mill a spot in cutter into each mandrel. So my second thought was to make something like a ridge reamer except it cuts with the bore. That way it's adjustable and I don't have to make one to fit each bore. My guess is he's made something like the later but for one or two squish bands I think the lathe setup is the way to go.
> 
> I also agree with mastermind, a center locating pin in the head would help with the lathe setup plus it would aid in holding the cylinder more securely.



well at least i got someome thinking.sorry if i got off on the wrong foot. i guess i'll keep my opinion to myself on the porting stuff.


----------



## srcarr52 (Dec 27, 2011)

tree monkey said:


> well at least i got someome thinking.sorry if i got off on the wrong foot. i guess i'll keep my opinion to myself on the porting stuff.



No worries. As in racing your not going to give someone your whole setup but you'll give them key bits and see what they fill in the gaps with. That way you both learn something.


----------



## HEAVY FUEL (Dec 27, 2011)

I don't get it. 

Tree monkey put up a picture of it dang near 2 years ago in a build thread, many people saw it, Will, you even commented on it twice in post 27 & 29, now he's getting jumped on for not showing his work. I'll just assume you forgot Will but funny how everyone piled on. I guess I don't blame him for deleting it. Btw, I've ran & own alot of saws built by most of you guys in this thread and just wanted to they all turn into powerhouses when you guys are done, some with pop-ups and some without. Keep up the good work.


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## HEAVY FUEL (Dec 27, 2011)

Randy, I didn't get to run the 346 you built for Wendell tho cuz its like taking a pacifier from 2 year old. WAAAHHHHH!!!


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## Mastermind (Dec 27, 2011)

HEAVY FUEL said:


> Randy, I didn't get to run the 346 you built for Wendell tho cuz its like taking a pacifier from 2 year old. WAAAHHHHH!!!



LMFAO......

The piling you mentioned was just a knee jerk reaction from a few very good people. We are all just hoping to learn a new trick or two. Treemonkey builds a hell of a strong saw and everyone knows that. If he wants to share something I'm all ears.


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## Hedgerow (Dec 27, 2011)

HEAVY FUEL said:


> Randy, I didn't get to run the 346 you built for Wendell tho cuz its like taking a pacifier from 2 year old. WAAAHHHHH!!!



I did when Wendell wasn't looking... It was a feisty little bugger...


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## HEAVY FUEL (Dec 27, 2011)

Mastermind said:


> LMFAO......
> 
> The piling you mentioned was just a knee jerk reaction from a few very good people. We are all just hoping to learn a new trick or two. Treemonkey builds a hell of a strong saw and everyone knows that. If he wants to share something I'm all ears.



I can't copy and paste from my phone,

Go to tree monkey's thread 6401 woods port build. If you want to get an idea why I'm confused.


----------



## Mastermind (Dec 27, 2011)

HEAVY FUEL said:


> I can't copy and paste from my phone,
> 
> Go to tree monkey's thread 6401 woods port build. If you want to get an idea why I'm confused.



Oh I had a little birdy tell me he deleted the pics of his tool pics. :msp_mellow:


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## blsnelling (Dec 27, 2011)

This forum thrives on the sharing of knowledge. That's what makes us what we are. Anything less won't fly far around here. Even us sponsors share info with each other related to saw building. I've championed that phylosophy as long as I've been here, and it's refreshing to see everyone working together. Many a time I've even refered someone to another builder when I was too busy or thought another builder was better with a particular model.


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## komatsuvarna (Dec 27, 2011)

blsnelling said:


> This forum thrives on the sharing of knowledge. That's what makes us what we are. Anything less won't fly far around here. Even us sponsors share info with each other related to saw building. I've championed that phylosophy as long as I've been here, and it's refreshing to see everyone working together. Many a time I've even refered someone to another builder when I was too busy or thought another builder was better with a particular model.



Good post Brad, I agree 100%. Im just a back woods hack country boy that likes making saws go faster. I've had help from* many and many* of members, a lot of them are sponsors and make money at what they were helping me with. I have no desire to build others saws, but I sure like messing with my own. I've learnt a lot from this site and its members, and i wouldn't care one bit to share back, of course I don't know much worth sharing.


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## tlandrum (Dec 27, 2011)

id share if i knew anything worth sharing


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## Mastermind (Dec 27, 2011)

blsnelling said:


> This forum thrives on the sharing of knowledge. That's what makes us what we are. Anything less won't fly far around here. Even us sponsors share info with each other related to saw building. I've championed that phylosophy as long as I've been here, and it's refreshing to see everyone working together. Many a time I've even refered someone to another builder when I was too busy or thought another builder was better with a particular model.



I feel the same way Brad. 

One of the best things that came out of Terry's GTGs was seeing that all the guys build strong running saws. Only a small margin separated the builder's saws, and the order would most likely change on different days.

Without you older members sharing your knowledge I would never be building a strong running ported saw. I plan to practice total transparency and share everything I learn with anyone that wants to try it. Will that cost me a customer? I seriously doubt it, most guys I've built saws for say they contacted me because of the detailed build threads I post. That and my wonderful personality.


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## blsnelling (Dec 27, 2011)

What little I know was learned from others that have shared. There's more that I don't know than what I do know, but I'll share what I do know.


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## Mastermind (Dec 27, 2011)

komatsuvarna said:


> Good post Brad, I agree 100%. Im just a back woods hack country boy that likes making saws go faster. I've had help from* many and many* of members, a lot of them are sponsors and make money at what they were helping me with. I have no desire to build others saws, but I sure like messing with my own. I've learnt a lot from this site and its members, and i wouldn't care one bit to share back, of course *I don't know much* worth sharing.





tlandrum2002 said:


> id share *if i knew anything* worth sharing



Says two of the very best saws builders I know. :msp_sneaky:


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## Tzed250 (Dec 27, 2011)

HEAVY FUEL said:


> I don't get it.
> 
> Tree monkey put up a picture of it dang near 2 years ago in a build thread, many people saw it, Will, you even commented on it twice in post 27 & 29, now he's getting jumped on for not showing his work. I'll just assume you forgot Will but funny how everyone piled on. I guess I don't blame him for deleting it. Btw, I've ran & own alot of saws built by most of you guys in this thread and just wanted to they all turn into powerhouses when you guys are done, some with pop-ups and some without. Keep up the good work.





Mastermind said:


> LMFAO......
> 
> The piling you mentioned was just a knee jerk reaction from a few very good people. We are all just hoping to learn a new trick or two. Treemonkey builds a hell of a strong saw and everyone knows that. If he wants to share something I'm all ears.




Maybe it was the smart aleck way in which he replied to the query????


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## FATGUY (Dec 27, 2011)

all this sharing is making me all warm and fuzzy. If anyone needs advice on the important things like eating or drinking beer, I'm your man.:hmm3grin2orange::hmm3grin2orange::hmm3grin2orange:


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## Mastermind (Dec 27, 2011)

Tzed250 said:


> Maybe it was the smart aleck way in which he replied to the query????



Well that is a possibility.............:taped:


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## komatsuvarna (Dec 27, 2011)

Tzed250 said:


> Maybe it was the smart aleck way in which he replied to the query????



It is hard to type personality.......happens to me some too,, although I mean nothing by it. Guess its just the way it comes off.


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## HEAVY FUEL (Dec 27, 2011)

I understand that but obviously have my wires crossed somewhere. My point is he did put up a picture of this now infamous cutter for everyone to see, now that he deleted it some are upset like they've never seen it before even after they commented on it in his thread.


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## Outlaw5.0 (Dec 27, 2011)

I can understand keeping "full on race saw" stuff secretive, but thats it. Some may do this for a living, and they view it as taking food off their table if they share. 

I love to share experiences, techniques and knowlege, it helps all of us move foward. There is no "I" in team as I have been taught many times, but thats just me.


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## ncfarmboy (Dec 27, 2011)

stihl038x2 said:


> Yep ! I probably would !!
> 
> Steve



I would also. That is why I'm *here* to help and learn! 
Shep


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## HEAVY FUEL (Dec 27, 2011)

Tzed250 said:


> Maybe it was the smart aleck way in which he replied to the query????



Oh definitely!!


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## parrisw (Dec 27, 2011)

HEAVY FUEL said:


> I don't get it.
> 
> Tree monkey put up a picture of it dang near 2 years ago in a build thread, many people saw it, Will, you even commented on it twice in post 27 & 29, now he's getting jumped on for not showing his work. I'll just assume you forgot Will but funny how everyone piled on. I guess I don't blame him for deleting it. Btw, I've ran & own alot of saws built by most of you guys in this thread and just wanted to they all turn into powerhouses when you guys are done, some with pop-ups and some without. Keep up the good work.





HEAVY FUEL said:


> I understand that but obviously have my wires crossed somewhere. My point is he did put up a picture of this now infamous cutter for everyone to see, now that he deleted it some are upset like they've never seen it before even after they commented on it in his thread.



Ok, I honestly have no idea about that. 2 years ago? Hell that was allot of posts ago, sometimes I can't remember what I posted a week ago. 

My point wasn't about showing me how he does it, I was just curious since he mentioned it, hell its only cutting a squish band, many people know how to do it, it aint gona change one thing if he shows how he does it. 

The point was he came across hacking us down on how we are doing it and his is better, then wont show it. Sorry just doesn't fly with me. If ya don't want to share your work, then just Zip IT.

So, lets just let it be. 

so how about windows in pistons? How do you guys feel about that.


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## Dennis Cahoon (Dec 27, 2011)

Has anyone given one of these a try?.......The rasp was Gypo's big secret, and he swore by them!.......and if I remember right, he won alot of GTG's.......Keep those pictures coming.........Hahahahahahaha!


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## blsnelling (Dec 27, 2011)

Is that what you use on the high dollar bike saws?


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## parrisw (Dec 27, 2011)

Dennis Cahoon said:


> Has anyone given one of these a try?.......The rasp was Gypo's big secret, and he swore by them!.......and if I remember right, he won alot of GTG's.......Keep those pictures coming.........Hahahahahahaha!



I thought he used a Horse Hoof Rasp??


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## Dennis Cahoon (Dec 27, 2011)

parrisw said:


> I thought he used a Horse Hoof Rasp??



You're Right, but just for ports......the smaller rasps were used for his head work.


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## blsnelling (Dec 27, 2011)

Dennis Cahoon said:


> .....the smaller rasps were used for his head work.



I've heard he could use some "head" work:hmm3grin2orange:


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## Dennis Cahoon (Dec 27, 2011)

blsnelling said:


> Is that what you use on the high dollar bike saws?




No Brad!.....I use lots of polish........mostly on the inside.......Hahahahahaha!


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## wigglesworth (Dec 27, 2011)

Dennis Cahoon said:


> No Brad!.....I use lots of polish........



I knew a Polish guy once....

He didn't know much about a chainsaw though.


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## parrisw (Dec 27, 2011)

Dennis Cahoon said:


> You're Right, but just for ports......the smaller rasps were used for his head work.



Right! LOL 



Dennis Cahoon said:


> No Brad!.....I use lots of polish........mostly on the inside.......Hahahahahaha!



That's pretty cool Dennis.


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## blsnelling (Dec 27, 2011)

Dennis Cahoon said:


> No Brad!.....I use lots of polish........mostly on the inside.......Hahahahahaha!



Wow, is that pretty! It's a shame it has to be hidden


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## Jacob J. (Dec 27, 2011)

Every "saw builder" here started somewhere and got some help along the way from someone. I remember when most of the current saw builders here were first learning how to hand file a square ground chain or modify the muffler on their saw. As already pointed out, people get better through the sharing of knowledge. In my case, I had my old man and a family friend who was a retired motocross and road bike racer. 

In the early days of this forum, a lot of guys acted like knowledge is power. Those guys are long gone. One builder who was here for a while would even JB Weld the heads on the cylinder bolts of saws he built so people couldn't easily get the cylinders off to look inside. That's just silly and to me, indicative of a narrow mind. Paranoia is a hallmark of the ignorant. I've shared what I know with a lot of people, many of whom have gone on to become better engine builders than me and I praise them for it. Knowledge alone won't allow someone to produce superior results. Motivation, innovation, intelligence, and determination are also parts of the equation. I buy saws and service now from the guys I shared stuff with way back when. However, I won't buy anything from someone who refuses to share what they know.


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## Dennis Cahoon (Dec 27, 2011)

blsnelling said:


> Wow, is that pretty! It's a shame it has to be hidden



Hidden is Good!


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## parrisw (Dec 27, 2011)

Jacob J. said:


> Every "saw builder" here started somewhere and got some help along the way from someone. I remember when most of the current saw builders here were first learning how to hand file a square ground chain or modify the muffler on their saw. As already pointed out, people get better through the sharing of knowledge. In my case, I had my old man and a family friend who was a retired motocross and road bike racer.
> 
> In the early days of this forum, a lot of guys acted like knowledge is power. Those guys are long gone. One builder who was here for a while would even JB Weld the heads on the cylinder bolts of saws he built so people couldn't easily get the cylinders off to look inside. That's just silly and to me, indicative of a narrow mind. Paranoia is a hallmark of the ignorant. I've shared what I know with a lot of people, many of whom have gone on to become better engine builders than me and I praise them for it. Knowledge alone won't allow someone to produce superior results. Motivation, innovation, intelligence, and determination are also parts of the equation. I buy saws and service now from the guys I shared stuff with way back when. However, I won't buy anything from someone who refuses to share what they know.




Well said JJ. Just by telling or showing someone how you do something doesn't mean they'll do it, or can do it, or come up with the same results, as you say there are many factors involved. Now I've had allot of help from this site, JJ and TW were the main two guys that helped me get going, gave me moral support more then anything else that helped me get the nuts to try my first saw.


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## Jacob J. (Dec 27, 2011)

parrisw said:


> Well said JJ. Just by telling or showing someone how you do something doesn't mean they'll do it, or can do it, or come up with the same results, as you say there are many factors involved. Now I've had allot of help from this site, JJ and TW were the main two guys that helped me get going, gave me moral support more then anything else that helped me get the nuts to try my first saw.



You ended up building one of the strongest saws I've ever had in my hands. That thing is sweet.


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## Dennis Cahoon (Dec 27, 2011)

.....just goes to show you.......anybody can build a worksaw!:hmm3grin2orange:


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## parrisw (Dec 27, 2011)

Jacob J. said:


> You ended up building one of the strongest saws I've ever had in my hands. That thing is sweet.



:msp_thumbup:


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## parrisw (Dec 27, 2011)

Dennis Cahoon said:


> .....just goes to show you.......anybody can build a worksaw!:hmm3grin2orange:



It ain't Rocket Surgery.


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## Tzed250 (Dec 27, 2011)

I make sure to stay in a Holiday Inn Express the night before I do a port job.


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## Tzed250 (Dec 27, 2011)

*Hahahahahahahaha!!!!!!!!!!!!!!!!!!!*

OK, i hope you guys get a kick out of this, I sure did. This is the add copy from an auction on eBay for a Husky 562XP. Unfrikkenbelievable!!

*THESE ARE WORK SAWS! I GET THAT QUESTION A FEW TIMES A DAY. 99% OF THE SAWS I DO ARE WORK SAWS. THESE ARE MORE RELIABLE AND WILL LAST MANY TIMES LONGER THAN A STOCK SAW. I DONT KNOW WHY PEOPLE KEEP THINKING THESE ARE NOT GOING TO LAST. ONE PERCENT OF MY SAWS ARE FOR COMPETITION USE AND RUN NITRO METHANE, THESE RUN PREMIUM GASOLINE





I JUST GOT THIS SAW IN AND ITS SOLD AS WELL. I WILL HAVE ANOTHER ONE ON THESE INSTOCK WITHIN A WEEK. I SOLD MY FIRST ONE LAST MONTH TO A LOGGER IN CANADA. I WILL HAVE THIS ONE DONE IN 12 DAYS OR SO AFTER I GET IT. IF YOU WANT IT BEFORE I GET IT COMPLETED I WILL STILL HAVE TIME TO BUILD TO YOUR SPECIFICATIONS. PLEASE SEE MY OTHER AUCTIONS ON 346XP'S SO YOU CAN GET AN IDEA OF WHAT THIS SAW WILL LOOK LIKE AND WHAT MODIFICATIONS WILL BE DONE TO IT. THESE ARE RARE BUT I WILL HAVE ANOTHER ONE INSTOCK!!

I started porting 2 stroke Motorcross bikes about 30 years ago for a well known racing company. I was head of R&D for them for 12 years. I have continued doing engine work since then including giant scale RC aircraft engines. They are basically chainsaw engines, including inline twin and upposed 2 and 4 cylinder models, all are 2 stroke. Since Motorcross has changed over to 4 stroke engines, I do not do much for the sport now. I have been building saw engines for the last 10 years or so. 

I do Husqvarna XP saws, as well as Stil pro and Dolmar Pro saws. I have done a few Echo saws and they work well modified. This saw has ceramic hybrid main bearings and a highly modified engine, with upgrades to the chassis. The crank is split and weight removed from both halves then balanced better than then come from the factory. This saw produces slightly over 5.8hp, up from the 4.7 stock rating. The intake is enlarged by 30% as well as the entire intake system port matched, from the airfilter to the cylinder. I can at your request block the saw from drawing hot air from inside the saw and only allow it to pull cool air from outside the saw. I remove the stock mixing screen in the rubber manifold because the manifold is enlarged as well as the entire intake tract is roughened to serve the brass screen's purpose. The limiters on the high and low speed jets are removed and the jets replaced one size larger. My saw's will have ZERO air leaks. The intake runners are enlarged by about 35%. I groove the transfer ports to give the charge a spiral motion and aim the charge at the intake side as to force out as much of the spent exhaust as possible. In other words I want to flow the fresh fuel/air mixture at the front of the cylinder wall to lift the exhaust gas out as completely as possible so that the only gas being pulled back in the exhaust port is fresh air/fuel, not burnt exhaust gasses. I mill around 1mm from the base of the cylinder and use a super thin base gasket to raise compression. The dome of the cylinder is polished to a mirror finish. I use SureFire V3 spark plugs. The piston is polished on the entire outer surface and the dome. Both intake and exhaust flanges are decked perfectly flat to ensure sealing. The exhaust port is enlarged by almost 45% and also polished to a mirror finish. The exhaust is port matched all the way into the hand built expansion chanber, I use 2 exhaust gaskets to insure sealing, the aluminum heat shield that seals against the exhaust port on a factory saw, gets a gasket on my saws. They are sprayed with Permatex copper sealant. Yes my saws actually have a functioning expansion chanber, instead of just adding a hole in the muffler and calling it a ported muffler. I use a 2000 degree ceramic high heat paint that will not burn off, so your muffler will not rust. I have applied for patent protection for my exhaust mufflers/ expansion chambers. I use a heat protection film under the top cover to keep the heat from the muffler from damaging the plastic top cover and keep it looking good. 3m clear film is used on all decals to keep the saw looking new.

These saws run on Royal Purple TCWIII synthetic oil at 100:1. When I do a full Ceramic bearing and ring version, including Ceramic needle bearings on both rod ends, these saws run on 150 to 200:1. Ceramic bearings are thousands of times rounder than metal bearings and therefore generate very little drag and produce almost no heat. You can put a full ceramic bearing on a dremel tool and spin it at 30,000 rpm and it never gets hot enough that you can't hold it. Do the same with a high quality steel bearing, like that come in these saws, and you have to let go after 5 seconds because it gets so hot. The saw comes with the Sugihara 18" OR 30", OR 32" bar and chain. I have 20" but they are hard nose bars.These bars are almost impossible to find anymore, but they are the finest bar ever produced. They have replaceable nose sprockets. I use a custom handle wrap that takes over 80% of the vibration out of the handle as well as making it about 30% larger. Your hand will not slip on this handle even when its raining!!

This will be the last saw you will ever buy, as long as you use the Royal Purple oil I spec and the correct ratio, and take care of your air filter. I offer 3 different Factory Husqvarna air filter choices. I have over 1000 hours on my 346 on the same ring, and its still got around a 160 some compression reading, (remember the milled cylinder base). This will be the fastest revving, hardest cutting 562 you can get your hands on, outside a full blown competition saw having a large motorcycle type expansion camber on it! My saw's come broken in with over 2 gallons of fuel through it. It has never cut wood and when you receive my saws you cant tell they were ever run. I break the engines in on a test stand not on the complete saw chassis. Believe me when I say they are ready to work when you get your saw, the engine does not want to be babied! Any question, please ask. 

Have a Merry Christmas and a Great New Year!*


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## gink595 (Dec 27, 2011)

Wow, that is very impressive...Someone needs their phd in the field of BS :msp_tongue:


Did you see the pictures of the port work? I'm not sure what kind of "machine" work he used to do the base but I think someone is wanting their Beaver back.


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## tlandrum (Dec 27, 2011)

??????????????????


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## parrisw (Dec 27, 2011)

LOL, what an Idoit! TCWIII is outboard oil. and at 200-1, that takes the cake.


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## tdi-rick (Dec 27, 2011)

Tzed250 said:


> OK, i hope you guys get a kick out of this, I sure did. This is the add copy from an auction on eBay for a Husky 562XP. Unfrikkenbelievable!!
> 
> *THESE ARE WORK SAWS! I GET THAT QUESTION A FEW TIMES A DAY. 99% OF THE SAWS I DO ARE WORK SAWS. THESE ARE MORE RELIABLE AND WILL LAST MANY TIMES LONGER THAN A STOCK SAW. I DONT KNOW WHY PEOPLE KEEP THINKING THESE ARE NOT GOING TO LAST. ONE PERCENT OF MY SAWS ARE FOR COMPETITION USE AND RUN NITRO METHANE, THESE RUN PREMIUM GASOLINE
> 
> ...



Wow. 

I'm swapping to those Surefire plugs and Royal Purple @ 150:1 right away !


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## parrisw (Dec 27, 2011)

Just looked at the add. Looks like he milled the cyl base with a file. Upper transfers are not touched, and lowers are hogged out allot. Ex port looks funny. Who knows maybe they run well. But what a load of BS.


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## mdavlee (Dec 27, 2011)

I just want to know how he removed the limiters on the autotune carb? And all that work to get 5.8 hp. I wonder if he has a dyno?


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## bluesportster02 (Dec 27, 2011)

he wants $1250 for it


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## HEAVY FUEL (Dec 27, 2011)

Does he spray the chain with autosharpening fluid too???


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## tdi-rick (Dec 27, 2011)

parrisw said:


> Just looked at the add. Looks like he milled the cyl base with a file. Upper transfers are not touched, and lowers are hogged out allot. Ex port looks funny. Who knows maybe they run well. But what a load of BS.




For everyone's enjoyment.


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## tlandrum (Dec 27, 2011)

so when are going to open it up? lolotstir:


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## rbmopar (Dec 27, 2011)

That cylinder base is the best. Butchered the bejesus out of it with a file, but you can still see the original machine marks on part of it. So he succesfully made it crooked without lowering it at all. At least he took good pictures of his fine work. What a tool.


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## wigglesworth (Dec 27, 2011)

tdi-rick said:


>



Dude must know his stuff. That's the ultra rare, very hard to duplicate late 70's muffler mod known as......

"The Travolta"....


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## bluesportster02 (Dec 27, 2011)

he also applied for a patent for the muffler :hmm3grin2orange::hmm3grin2orange:


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## gink595 (Dec 27, 2011)

bluesportster02 said:


> he also applied for a patent for the muffler :hmm3grin2orange::hmm3grin2orange:



Yeah I'm sure the EPA is going to love that:hmm3grin2orange:


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## RTK (Dec 27, 2011)

Tzed250 said:


> OK, i hope you guys get a kick out of this, I sure did. This is the add copy from an auction on eBay for a Husky 562XP. Unfrikkenbelievable!!
> 
> *THESE ARE WORK SAWS! I GET THAT QUESTION A FEW TIMES A DAY. 99% OF THE SAWS I DO ARE WORK SAWS. THESE ARE MORE RELIABLE AND WILL LAST MANY TIMES LONGER THAN A STOCK SAW. I DONT KNOW WHY PEOPLE KEEP THINKING THESE ARE NOT GOING TO LAST. ONE PERCENT OF MY SAWS ARE FOR COMPETITION USE AND RUN NITRO METHANE, THESE RUN PREMIUM GASOLINE
> 
> !*




You wouldn't happen to have a link to that?? The RC racing community is very small and it would be interesting to see who this is..


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## Tzed250 (Dec 27, 2011)

I think he ported it with a kitchen mixer...


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## tdi-rick (Dec 27, 2011)

Check out the 346 too 

google "Hot-Rod-Ported-Polished-Husqvarna-346XP-Chainsaw-Dirty-Saw-non-X-Torq-NO-EPA"


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## Tzed250 (Dec 27, 2011)

tdi-rick said:


> Check out the 346 too
> 
> google "Hot-Rod-Ported-Polished-Husqvarna-346XP-Chainsaw-Dirty-Saw-non-X-Torq-NO-EPA"



Stage 5 Port Polish!!!!!!!:hmm3grin2orange::hmm3grin2orange::hmm3grin2orange:


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## bluesportster02 (Dec 27, 2011)

RTK said:


> You wouldn't happen to have a link to that?? The RC racing community is very small and it would be interesting to see who this is..


New Hot Rod Ported Polished Husqvarna 562XP Chainsaw Dirty Saw | eBay


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## gink595 (Dec 27, 2011)

Tzed250 said:


> Stage 5 Port Polish!!!!!!!:hmm3grin2orange::hmm3grin2orange::hmm3grin2orange:



LOL, I seen that...WTF...I like the 70's American Flyer 10 speed bar tape on the handle:hmm3grin2orange:


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## ECsaws (Dec 27, 2011)

RTK said:


> You wouldn't happen to have a link to that?? The RC racing community is very small and it would be interesting to see who this is..



The real [email protected] circuit (alkyl Nitro) is fairly tight also Ive neaver heard of anyone from that area be curious to know who this guy is. Wonder if someone from this forum... :msp_ohmy:


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## tdi-rick (Dec 27, 2011)

ECsaws said:


> The real [email protected] circuit is fairly tight also Ive neaver heard of anyone from that area be curious to know who this guy is. *Wonder if someone from this forum...* :msp_ohmy:



i was wondering the same thing EC :monkey:


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## bluesportster02 (Dec 27, 2011)

i seen this add a few days ago and was hoping it was not anyone hears add


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## gink595 (Dec 27, 2011)

ECsaws said:


> The real [email protected] circuit (alkyl Nitro) is fairly tight also Ive neaver heard of anyone from that area be curious to know who this guy is. Wonder if someone from this forum... :msp_ohmy:




Didn't it say Ashland :msp_tongue:


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## Mastermind (Dec 27, 2011)

ECsaws said:


> The real [email protected] circuit (alkyl Nitro) is fairly tight also Ive neaver heard of anyone from that area be curious to know who this guy is. Wonder if someone from this forum... :msp_ohmy:



The work is far too clean for it to be me. :msp_unsure:


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## husq2100 (Dec 27, 2011)

great, just great....I was going to bid on those saws, but now all of AS knows about them the price will be driven through the roof, for the latest stage 5 engine builder works saw......thanks alot guys :msp_mad:


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## bluesportster02 (Dec 27, 2011)

husq2100 said:


> great, just great....I was going to bid on those saws, but now all of AS knows about them the price will be driven through the roof, for the latest stage 5 engine builder works saw......thanks alot guys :msp_mad:



sorry :hmm3grin2orange::hmm3grin2orange::hmm3grin2orange:


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## blsnelling (Dec 27, 2011)

This guy's 346s have been on Ebay for a while.


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## gink595 (Dec 27, 2011)

blsnelling said:


> This guy's 346s have been on Ebay for a while.



Yeah I think it will stay that way too:msp_tongue:


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## blsnelling (Dec 27, 2011)

gink595 said:


> Yeah I think it will stay that way too:msp_tongue:



No doubt!


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## parrisw (Dec 27, 2011)

Ya, I've seen that dude's saw a while back on Ebay as well. Someone should ask for a vid.


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## mdavlee (Dec 27, 2011)

He had some videos of the 346s on there last time. He had it sitting on cardboard on a driveway and had a stocker there and just started and revved them both to show a difference.


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## parrisw (Dec 27, 2011)

mdavlee said:


> He had some videos of the 346s on there last time. He had it sitting on cardboard on a driveway and had a stocker there and just started and revved them both to show a difference.



Or right. I remember that now.


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## husq2100 (Dec 28, 2011)

I asked him about the so called crank work, where he says splitting it for better balancing....His response "No sorry I actually have to send the crank out, I dont have the machine's, scales, tools to do that in my place. I know how to do it, we used to do that where I worked, I just never invested in the hardware. Thanks,jeff"


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## rms61moparman (Dec 28, 2011)

ECsaws said:


> The real [email protected] circuit (alkyl Nitro) is fairly tight also Ive neaver heard of anyone from that area be curious to know who this guy is. *Wonder if someone from this forum.*.. :msp_ohmy:





It looks like something I would do to a saw but it isn't me!!!LOL


Mike


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## blsnelling (Dec 28, 2011)

rms61moparman said:


> It looks like something I would do to a saw but it isn't me!!!LOL
> 
> 
> Mike



Except, without all the BS. Hey! Wait a minute! That's my initials, lol.


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## rms61moparman (Dec 28, 2011)

blsnelling said:


> Except, without all the BS. Hey! Wait a minute! That's my initials, lol.







Oh BELIEVE me Brad

We have known they were your initials for a WHILE!!!

Quite often I will hear someone say" Have you heard from ol' BS lately?".
I always know they are speaking of you!LOL

Mike


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## blsnelling (Dec 28, 2011)

rms61moparman said:


> Oh BELIEVE me Brad
> 
> We have known they were your initials for a WHILE!!!
> 
> ...



Merry Christmas to you too, you old buzzard!:hmm3grin2orange:


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## rms61moparman (Dec 28, 2011)

blsnelling said:


> Merry Christmas to you too, you old buzzard!:hmm3grin2orange:





We have the most fun on this site that a guy can have with his clothes on!!!


Mike


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## blsnelling (Dec 28, 2011)

rms61moparman said:


> We have the most fun on this site that a guy can have with his clothes on!!!
> 
> 
> Mike



And you can just keep your clothes on...including your shirt!!!


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## rms61moparman (Dec 28, 2011)

blsnelling said:


> And you can just keep your clothes on...including your shirt!!!






...Does something to ya when you see me with my shirt off doesn't it???LOL


Mike


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## shwinecat (Dec 28, 2011)

I was wondering how long it would take for this guys super saws on ebay to be revealed but I did not want to say anything out of fear it might be somone on the sight. Someone has to at least invite him to a GTG. I am sure there are a few builders on here that would humbly run there saws against his. I would pay his plane ticket to see him come to Grandpa Tractors GTG to cut against Tree Monkey's 064 I saw two years ago. 

All bull aside this is the best thread I have read in a long time an I hope it does not end with hard feelings. I have only met Tree Monkey once in my life and he can not only build a strong saw but he can run one with the best of them.


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## MacLaren (Dec 28, 2011)

shwinecat said:


> I was wondering how long it would take for this guys super saws on ebay to be revealed but I did not want to say anything out of fear it might be somone on the sight. Someone has to at least invite him to a GTG. I am sure there are a few builders on here that would humbly run there saws against his. I would pay his plane ticket to see him come to Grandpa Tractors GTG to cut against Tree Monkey's 064 I saw two years ago.
> 
> All bull aside this is the best thread I have read in a long time an I hope it does not end with hard feelings. I have only met Tree Monkey once in my life and he can not only build a strong saw but he can run one with the best of them.



I hear ya man. After running the 660 Scott did for me, I cant ever see goin back to pop ups........


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## srcarr52 (Dec 28, 2011)

blsnelling said:


> This guy's 346s have been on Ebay for a while.



I wrote something on it in the "Seen it on Craigslist/eBay" thread about 3 weeks ago. Just about everything he writes about is a gimmick of some sort but to top it all off I went looking back through his feedback and low and behold, someone has bought a 346 from him. :biggrin:


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## MacLaren (Dec 28, 2011)

srcarr52 said:


> I wrote something on it in the "Seen it on Craigslist/eBay" thread about 3 weeks ago. Just about everything he writes about is a gimmick of some sort but to top it all off I went looking back through his feedback and low and behold, someone has bought a 346 from him. :biggrin:



Is this the 346 with the silver tape all around the handle bar?


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## srcarr52 (Dec 28, 2011)

MacLaren said:


> Is this the 346 with the silver tape all around the handle bar?



and the alien antenna muffler, yes!


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## edisto (Dec 28, 2011)

Tzed250 said:


> Stage 5 Port Polish!!!!!!!:hmm3grin2orange::hmm3grin2orange::hmm3grin2orange:



Is that tape or resin he coated the piston top and exhaust port with? It looks like resin, but it wrinkles like tape.


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## sps3172 (Dec 28, 2011)

Catch me up.....

Why, again, is everyone bashing this ebay seller?

He seems to be performing the standard "treat the engine like it's a V-8 cylinder head", 'port' job that goes over so well here on AS. 

Is the bashing because his pricing is out of line?


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## parrisw (Dec 28, 2011)

sps3172 said:


> He seems to be performing the standard "treat the engine like it's a V-8 cylinder head", 'port' job that goes over so well here on AS.
> 
> ?



Really care to explain what and who?

Why don't you post up some of you're work.


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## sps3172 (Dec 28, 2011)

parrisw said:


> Really care to explain what and who?
> 
> Why don't you post up some of you're work.



Not sure I understand the question here????

To rephrase my first post....

This guy on eBay seems to be doing all the stuff that I see in 'porting' threads here on AS. I was confused why everyone was speaking poorly of his work.

I feel like I'm missing the joke......that's why I asked.


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## stihlbro (Dec 28, 2011)

It appears a 562 is for sale by the ad., the pictures look to be a 346 to me. The sales pitch speaks for itself. The whole ceramic bearings, 200 to 1 oil mix, 30 or 32 inch bar, and the special sparkplug sounds kinda farfetched. Not saying anything bad, but doesn't sound like a deal I would get involved with. I would like to see a video of the saw in some wood.


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## stihlbro (Dec 28, 2011)

To stay on subject, I wonder if a pop up piston would help the 562 as advertised? :msp_unsure:


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## RTK (Dec 28, 2011)

Ceramic bearings are pretty slick, no pun intended


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## rms61moparman (Dec 28, 2011)

RTK said:


> Ceramic bearings are pretty slick, no pun intended



The ones I've seen used didn't really give any noticeable increase at work saw performance levels.
I'm sure they would be more necessary in a racer.


Mike


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## Jacob J. (Dec 28, 2011)

sps3172 said:


> Catch me up.....
> 
> Why, again, is everyone bashing this ebay seller?
> 
> ...



It's not the pricing so much as it's the appearance of certain things. 
The base of the cylinder obviously wasn't cut on a lathe or a mill, it looks hand-done. You can't get
real precision with a file by hand when cutting the base of a cylinder. If the base isn't square, the saw
isn't going to last long. 
The transfer ports are way hogged out, which is not conducive to real power, especially in the smaller
quad-port saws. 

I think people are critiquing more than bashing, but you need to understand that there are some 
serious enthusiasts on this site. We're talking about people who've purchased commercial-grade
lathes and mills and have learned how to use them for small engine modification.


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## Jacob J. (Dec 28, 2011)

sps3172 said:


> Not sure I understand the question here????
> 
> To rephrase my first post....
> 
> ...



Not to mention there's professional machinists and fabricators here who do serious, precision work and they're livelihood depends on top-grade results.


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## parrisw (Dec 28, 2011)

sps3172 said:


> Not sure I understand the question here????
> 
> To rephrase my first post....
> 
> ...



You made a pretty blanket statement about the people on this site, saying they do just as poor quality work like this fellow in question. I was simply asking you to back up you're statement. And since you seem to know how it's supposed to be done, sine you're qualified to comment on said port work, that you post up some of you're pro work for us all to see how it's supposed to be done.


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## sps3172 (Dec 28, 2011)

Jacob J. said:


> It's not the pricing so much as it's the appearance of certain things.
> The base of the cylinder obviously wasn't cut on a lathe or a mill, it looks hand-done. You can't get
> real precision with a file by hand when cutting the base of a cylinder. If the base isn't square, the saw
> isn't going to last long.
> ...



Thanks for the civil answer. I suppose I hadn't noted the quality of the surface finish....etc. I just took a quick glance at his ad and noted that he was selling a rather expensive 'ported' saw. That's about where I jumped in and asked to be 'caught up'. I didn't realize it was so easy to inadvertently 'step in it' here on AS. 



parrisw said:


> You made a pretty blanket statement about the people on this site, saying they do just as poor quality work like this fellow in question. I was simply asking you to back up you're statement. And since you seem to know how it's supposed to be done, sine you're qualified to comment on said port work, that you post up some of you're pro work for us all to see how it's supposed to be done.



See above. I never realized that I was 'saying' anything about the quality of anyone's work. Sorry if that rubbed you the wrong way.


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## Jacob J. (Dec 28, 2011)

sps3172 said:


> Thanks for the civil answer. I suppose I hadn't noted the quality of the surface finish....etc. I just took a quick glance at his ad and noted that he was selling a rather expensive 'ported' saw. That's about where I jumped in and asked to be 'caught up'. I didn't realize it was so easy to inadvertently 'step in it' here on AS.



I've seen the Ad several times myself and actually, if it wasn't so gimmicky and the finish of the porting work (and machining of the cylinder) was a lot
better, then it would be a hotrod little saw. Obviously the seller wants to produce a good commodity but he hasn't done his homework. The guys
here that build strong, strong saws could give him some pointers for sure.


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## srcarr52 (Dec 28, 2011)

Jacob J. said:


> I've seen the Ad several times myself and actually, if it wasn't so gimmicky and the finish of the porting work (and machining of the cylinder) was a lot
> better, then it would be a hotrod little saw. Obviously the seller wants to produce a good commodity but he hasn't done his homework. The guys
> here that build strong, strong saws could give him some pointers for sure.



From the sound of his adds I think he'd try to give the builders from this site some pointers. :hmm3grin2orange:
Something tells me that you couldn't get him to shut up long enough to tell him anything.


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## parrisw (Dec 28, 2011)

sps3172 said:


> See above. I never realized that I was 'saying' anything about the quality of anyone's work. Sorry if that rubbed you the wrong way.



No worries.


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## Mastermind (Dec 28, 2011)

parrisw said:


> No worries.



Now I'm really worried. :msp_mad:


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## HEAVY FUEL (Dec 28, 2011)

srcarr52 said:


> From the sound of his adds I think he'd try to give the builders from this site some pointers. :hmm3grin2orange:
> Something tells me that you couldn't get him to shut up long enough to tell him anything.



I think that just goes along with any of those big
Husky owners!!!:hmm3grin2orange:


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## jimdad07 (Dec 28, 2011)

I don't venture out of the fight thread very often, but there has been some good reading in this on port work and such. My take is that I have been doing mild in and out porting on a few saws now with good results, not doing much with the transfers but I have been opening up the windows a little more to lighten the piston more than anything. I can see the merit in pop-ups but I do not have much experience with them.


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## Metals406 (Dec 28, 2011)

I'd like to see treemonkey's tool (get your mind out of the gutter ). . . This place is pretty big, and a lot of threads come and go without me noticing.

I don't have a lathe or milling machine, so having a hand tool would kick some serious ass.

On pop-ups, I've been wanting to try an idea for quite a while now, but don't have the resources to do it.

Essentially, it would be a popup piston, that would be at zero on the intake side, and slope toward the exhaust to -- lets say -- .040". Or .020" on the intake side, and .040" on the exhaust side. My thoughts behind this was it would encourage charge to stay on the intake side because of the ramp effect, but essentially be flat to not cause too much disruption.

Neat thread so far.


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## tree monkey (Dec 28, 2011)

sps3172 said:


> Thanks for the civil answer. I suppose I hadn't noted the quality of the surface finish....etc. I just took a quick glance at his ad and noted that he was selling a rather expensive 'ported' saw. That's about where I jumped in and asked to be 'caught up'. I didn't realize it was so easy to inadvertently 'step in it' here on AS.
> 
> 
> 
> See above. I never realized that I was 'saying' anything about the quality of anyone's work. Sorry if that rubbed you the wrong way.



these guys are a little jumpy arent thay.

how can/ would these guys cut down some one elses work without using the end product?
this guy might know more then you think. just don't have the tools to do a better job.some of my first work was realy ugly but ran good.

i do things out of the norm all the time. its how you learn what works and what does not.

or you can just copy what someone else is doing and not realy learn anything.

btw i don't think this topic would have came up if i had not said that i cut the squish in pauls 660 and the 372 build off saws.


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## parrisw (Dec 29, 2011)

tree monkey said:


> these guys are a little jumpy arent thay.
> 
> how can/ would these guys cut down some one elses work without using the end product?
> this guy might know more then you think. just don't have the tools to do a better job.some of my first work was realy ugly but ran good.
> ...



One look at the guys butcher job on the cyl base is all I needed to see. 

How do you think the saw will last with the cylinder not sitting square on the case?

I assure you that, some if not most of us have known about cutting squish bands before you were around here posting. I've just never got around to trying it, and this thread gave me a kick start to give it a go. Besides this thread wasn't about cutting squish bands.


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## tree monkey (Dec 29, 2011)

parrisw said:


> One look at the guys butcher job on the cyl base is all I needed to see.
> 
> How do you think the saw will last with the cylinder not sitting square on the case?



how do you know it doesnt? did you check it to know?
at least this guy is thinking for himself unlike you


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## Jacob J. (Dec 29, 2011)

parrisw said:


> Besides this thread wasn't about cutting squish bands.



This thread is about eating Wasabi potato chips and drinking sparkling apple cider, which is what I'm currently doing.


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## parrisw (Dec 29, 2011)

tree monkey said:


> how do you know it doesnt? did you check it to know?
> at least this guy is thinking for himself unlike you



Because I have a pair of eyes. Look at it. Its the first thing I noticed, not because JJ said it. You can still see the factory machine marks on the top left and he's filed the chit out of the rest, and if you can't see that, maybe you should go have your eyes tested. Why would you say I'm not thinking for myself, you don't like anyone challenging you? You're defending this guy pretty hard, is it your handy work?


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## MacLaren (Dec 29, 2011)

parrisw said:


> One look at the guys butcher job on the cyl base is all I needed to see.
> 
> How do you think the saw will last with the cylinder not sitting square on the case?
> 
> I assure you that, some if not most of us have known about cutting squish bands before you were around here posting. I've just never got around to trying it, and this thread gave me a kick start to give it a go. Besides this thread wasn't about cutting squish bands.



Have you checked Scott's join date? Will, Scott was only tryin to help ya. It may have hit ya the wrong way, but thats how i saw it. But Scott nor anyone else is/should be obligated to show all thier work. Not all builders do show everything. Even I know that. Maybee you oughta have another cold one and chill out. Everyone has an opinion too. Lets just try and keep it civil.


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## parrisw (Dec 29, 2011)

MacLaren said:


> Have you checked Scott's join date? Will, Scott was only tryin to help ya. It may have hit ya the wrong way, but thats how i saw it. But Scott nor anyone else is/should be obligated to show all thier work. Not all builders do show everything. Even I know that. Maybee you oughta have another cold one and chill out. Everyone has an opinion too. Lets just try and keep it civil.



First off, yes I saw his join date, did you see his post count? So he's not been an active member here at all, which I don't care about, was just saying since apparently this thread is all because of him saying he cut a squish band. Second he wasn't trying to help at all, show me where he was trying to help me by saying how he can do it much faster, then wont show how, like I said before I don't care if someone wont show their work, just don't run your mouth about it then. Opinions are fine by me, that's not what he's stating. I'll refrain comment if he does, until then I ain't gona shutup.


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## tree monkey (Dec 29, 2011)

parrisw said:


> First off, yes I saw his join date, did you see his post count? So he's not been an active member here at all, which I don't care about, was just saying since apparently this thread is all because of him saying he cut a squish band. Second he wasn't trying to help at all, show me where he was trying to help me by saying how he can do it much faster, then wont show how, like I said before I don't care if someone wont show their work, just don't run your mouth about it then. Opinions are fine by me, that's not what he's stating. I'll refrain comment if he does, until then I ain't gona shutup.



tell ya what. i'll show some of my out of the norm work if you show me something you did that no one else has.

ill be back in a few min with my pics


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## parrisw (Dec 29, 2011)

tree monkey said:


> tell ya what. i'll show some of my out of the norm work if you show me something you did that no one else has.
> 
> ill be back in a few min with my pics



You want to see anything I've done, just click on my username and see all started threads, I've already posted everything I've done, everyone here already knows that, I'm not gona repost anything just for you, I've never claimed to be anything great, unlike you. Again you're not getting my point at all, my point was about your attitude, not you sharing your work, nothing worse then someone running their mouth about something then refusing to back it up, that's what got me all excited, maybe you'll get it this time, maybe you wont. You seem kinda thick.


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## tree monkey (Dec 29, 2011)

View attachment 213948

View attachment 213949

View attachment 213950

lol. here are some pics.
i'm not mad, i don't have an attitude problem, i'm just having fun.


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## MacLaren (Dec 29, 2011)

tree monkey said:


> View attachment 213948
> 
> View attachment 213949
> 
> ...



Well, I tell ya one thing Scott. I cant wait to get my hands on the 390XP when you get done with it. :hmm3grin2orange::hmm3grin2orange:
Im goin to bed now. See you guys tomorrow. :msp_thumbup:


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## parrisw (Dec 29, 2011)

tree monkey said:


> View attachment 213948
> 
> View attachment 213949
> 
> ...



Looks interesting. Doesn't look anything like no woods saw though, which we are talking about.


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## tree monkey (Dec 29, 2011)

nite paul

parrisw, for some reason i like you, don't know why.iv'e helped you in the past and i'll help you in the future. but i just can't show you my tool. wife says i should not be flashing it around on the net.:hmm3grin2orange:

when i started porting saws, the only help i got was raise the ex port and lower the in port.


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## parrisw (Dec 29, 2011)

tree monkey said:


> nite paul
> 
> parrisw, for some reason i like you, don't know why.iv'e helped you in the past and i'll help you in the future. but i just can't show you my tool. wife says i should not be flashing it around on the net.:hmm3grin2orange:
> 
> when i started porting saws, the only help i got was raise the ex port and lower the in port.



LOL. Never said I hated ya, just butting heads a little is all. No worries on my end dude.

Oh BTW, I found the pics of your tool, and I'm not talking about the one in your pants. Can I post them? Pretty much as I imagined it would be. 1/4" HSS lathe bit as a cutter, on a steel mandrel. You should be more careful about the background of your other pics!! LOL


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## tree monkey (Dec 29, 2011)

ya go ahead. it ant no secret


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## parrisw (Dec 29, 2011)

tree monkey said:


> ya go ahead. it ant no secret



LOL. Then what was the big deal in the first place. 

I duno, I don't want ya to get pissed that I dug up some of your photos and posted them. 

How about I leave it to you to post them! LOL.

Its a good idea the way you do it. I'll still stick to doing it on the lathe. I feel its more even that way. I'm sure your way works fine for you though.


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## tree monkey (Dec 29, 2011)

lol i didn't make a big deal out of it,you did.or some one did.

i like making people think about things before i give an answer.


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## parrisw (Dec 29, 2011)

tree monkey said:


> lol i didn't make a big deal out of it,you did.or some one did.
> 
> i like making people think about things before i give an answer.



LOL, right. Well I didn't make a big deal out of not seeing your tool! Maybe I made a big deal about how you went about it is all, not too worry, its all good.

Nice, I do the same thing at work with apprentice's, make em think, you learn better that way.


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## tree monkey (Dec 29, 2011)

now were are on the same page:hmm3grin2orange:


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## parrisw (Dec 29, 2011)

tree monkey said:


> now were are on the same page:hmm3grin2orange:



:msp_thumbup:


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## Tzed250 (Dec 29, 2011)

I can hear Kumbaya in the background...


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## jimdad07 (Dec 29, 2011)

Another saw builder pi$$ing match ended with hugs:hmm3grin2orange:. That's what I love about this place. :msp_thumbsup:


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## gink595 (Dec 29, 2011)

tree monkey said:


> tell ya what. i'll show some of my out of the norm work if you show *me something you did that no one else has.*
> 
> ill be back in a few min with my pics





tree monkey said:


> View attachment 213948
> 
> View attachment 213949
> 
> ...



I wouldn't call those pictures of your work something that no one else has done, looks like a typical race saw build :hmm3grin2orange:

Did the epoxied studs work with the intake block? I've seen numerous ways of bolting a block on and they all look like a PITA to do. I've welded all the ones I've done so far and wouldn't do it any other way...unless you machine to much of the weld off


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## srcarr52 (Dec 29, 2011)

Since we are all sharing now I'll post something I did that I think is a little out of the norm. I did this on my build off 371/2, it probably would have placed better if I would have had time to break it in before it went of to battle. Sorry if you've seen it before. 

Ever wanted to have more transfer timing on a 371/2 and keep the entrance nice and flat?

Not the best welding, the old sine wave tig welder's arc likes to jump around a lot in tight places.






Blended in and blasted so it's not obvious.


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## wigglesworth (Dec 29, 2011)

I've seen TM's chamber tool. In fact, it was still on his old threads up until recently. It's really nothing to get all in a huff about fella's. There's no way it cuts as true as doing it the old fashioned way...

At least in my opinion.


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## gink595 (Dec 29, 2011)

This is how I weld pistons to make a pop up so you don't have to cut the base. I make these blocks that fit the piston slide them in and clamp them snug and weld away. It keeps the piston from wanting to warp. The bad thing is I have to make one for each piston size.


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## wigglesworth (Dec 29, 2011)

I've welded a couple up Gink. 

This one is the latest...






No jig, just weld for a couple seconds, and quench. I measured in several different locations prior to welding, and found no change afterwards. It's currently chugging away in a ms390. 

I am using a miller 252 and an aluminum spool gun. 

Here is the first one I did. Can u guess the piston Gink?


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## gink595 (Dec 29, 2011)

wigglesworth said:


> I've welded a couple up Gink.
> 
> This one is the latest...
> 
> ...




The ones I tried to Tig weld without anything to hold it in place warped miserable, they wouldn't even fit back in the bore! Maybe because you are using a spool gun where it is point and go you don't overheat the piston and can get in and out where with TIG welding it you pretty much go as fast as a turtle while driving all kinds of heat into the piston? Doesn't the spool gun make a mess trying to weld that small of a area? I'd like to see what it looks like after welding one.


If I had to guess I'd say it is a P5000 piston!


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## wigglesworth (Dec 29, 2011)

gink595 said:


> The ones I tried to Tig weld without anything to hold it in place warped miserable! Maybe because you are using a spool gun where it is point and go you don't overheat the piston and can get in and out where with TIG welding it you pretty much go as fast as a turtle while driving all kinds of heat into the piston? Doesn't the spool gun make a mess trying to weld that small of a area? I'd like to see what it looks like after welding one.
> 
> 
> If I had to guess I'd say it is a P5000 piston!



Nah, no mess at all. As long as the feed rate and amperage are right, it looks just like a mug weld. I'll look thru my pics and see if I have an after welded pic....

And yes, ur spot on on the slug


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## o8f150 (Dec 29, 2011)

i hate windows xp and those dang pop ups that want you to buy something:biggrin::biggrin::biggrin::biggrin::biggrin::biggrin: sorry i just couldn't resist


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## HEAVY FUEL (Dec 29, 2011)

o8f150 said:


> i hate windows xp and those dang pop ups that want you to buy something:biggrin::biggrin::biggrin::biggrin::biggrin::biggrin: sorry i just couldn't resist



I've been waiting for that one since this thread started!


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## Jacob J. (Dec 29, 2011)

wigglesworth said:


> I've seen TM's chamber tool. In fact, it was still on his old threads up until recently. It's really nothing to get all in a huff about fella's. There's no way it cuts as true as doing it the old fashioned way...
> 
> At least in my opinion.



That's why I would have it done on a lathe if I were going to cut the squish band. David did one years ago in a build-off thread using emery cloth glued on top of an old piston and that turned out well for a low-buck hillbilly build-off. But cutting significant material out of there requires real precision.


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## Metals406 (Dec 29, 2011)

tree monkey said:


> all this is cool , and fun. but i made hand tools that will do the same thing in about 15 min with no setup time.



Are these your tools or some other dudes?


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## parrisw (Dec 29, 2011)

Metals406 said:


> Are these your tools or some other dudes?



Yes that looks like it. 

I've wondered what would happen when you stop cutting, will you end up with a ridg. And how do you accurately remove a specific amount of material? I'm guessing an even cut would be very dependant on pressure applied to the tool. But those are all just guess's based on my thoughts.


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## Metals406 (Dec 29, 2011)

parrisw said:


> Yes that looks like it.
> 
> I've wondered what would happen when you stop cutting, will you end up with a ridg. And how do you accurately remove a specific amount of material? I'm guessing an even cut would be very dependant on pressure applied to the tool. But those are all just guess's based on my thoughts.



I'm thinking there is some ridge, hence he finished with the sandpaper mandrel, but maybe not?

Obviously his system works, as he builds some really fast saws.

His design is different than I imagined. . . I pictured something like how a forstner bit cuts.

A guy could control depth of cut if you had an adjustable screw in the center that limited bite.


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## ECsaws (Dec 29, 2011)

Another example of a pop - up piston.


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## parrisw (Dec 29, 2011)

ECsaws said:


> Another example of a pop - up piston.



Cool, I've always thought about doing more of a dome like that instead of the standard popup.


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## steve316 (Dec 29, 2011)

*dolmar 7900*

With the chamber being off set in a dolmar instead of centered like husqvarna or stihl.cuting squish ban makes more sence. Also I have been wanting ask if anyone has ever gas ported a chainsaw piston,either vertical or horsonal. this helps in sealing up the cylinder witch would ade in compression.just one of my brain cramps.:msp_confused:Steve


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## FATGUY (Dec 29, 2011)

what's gas porting?


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## Jacob J. (Dec 29, 2011)

FATGUY said:


> what's gas porting?



It's when the seam of your boxers starts coming apart after a large meal of chili, Fritos, and dark beer.


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## srcarr52 (Dec 29, 2011)

steve316 said:


> With the chamber being off set in a dolmar instead of centered like husqvarna or stihl.cuting squish ban makes more sence. Also I have been wanting ask if anyone has ever gas ported a chainsaw piston,either vertical or horsonal. this helps in sealing up the cylinder witch would ade in compression.just one of my brain cramps.:msp_confused:Steve



I have done horizontal gas ports on a saw piston before. I didn't have time to test before and after so I don't know if it was worth anything.


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## ECsaws (Dec 29, 2011)

FATGUY said:


> what's gas porting?



To "me" its when your drill the piston to force the ring into the cly wall .
yes I have done it may times not sure its worth the extra work


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## steve316 (Dec 29, 2011)

*gas porting*

has been around sence 60's. It is a hole drilled from the top of the piston down the back of the ring land to about the middle of the ring land.also can bee drilled horsonal which end up looking like a half moon slot in top of the ring land. the idea is your compression helps in ring seal. hope this is clear as mud.Steve


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## steve316 (Dec 29, 2011)

*gas porting*

the porting is add down force to the top ring helping the seal between the botton of the ring and the piston.steve


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## HELSEL (Dec 29, 2011)

Yep this is interesting !!!


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## HELSEL (Dec 29, 2011)

Interested to see if the pop up
can com up with some gain.


----------



## Tzed250 (Dec 29, 2011)

HELSEL said:


> Interested to see if the pop up
> can com up with some gain.





Pop-up Video????


----------



## Dennis Cahoon (Dec 29, 2011)

ECsaws said:


> Another example of a pop - up piston.



Did you recut your squish Woodsjunkie?......Hahahahahaha!


----------



## HELSEL (Dec 29, 2011)

Tzed250 said:


> Pop-up Video????



Depending on the video!!!!


----------



## parrisw (Dec 29, 2011)

Dennis Cahoon said:


> Did you recut your squish Woodsjunkie?......Hahahahahaha!



I would think you would have to with a piston like that.


----------



## tree monkey (Dec 29, 2011)

Metals406 said:


> Are these your tools or some other dudes?



lol no its not mine.

my squish is within 1/2 thow. is that klos e nuf?


----------



## parrisw (Dec 29, 2011)

tree monkey said:


> lol no its not mine.
> 
> my squish is within 1/2 thow. is that klos e nuf?



Similar? 

If your happy with it that's all that matters. I'd be just peachy with .0005".


----------



## jropo (Dec 29, 2011)

Well I couldn't resist. I saw that this was were all the cool kids were hanging out and just read the 32 pages to get caught up. Very interesting! I think is safe to say that a pop-up would be more of pita than what its worth, unless its for a unlimited hot saw.


----------



## Mastermind (Dec 29, 2011)

jropo said:


> Well I couldn't resist. I saw that this was were all the cool kids were hanging out and just read the 32 pages to get caught up. Very interesting! *I think is safe to say that a pop-up would be more of pita than what its worth*, unless its for a unlimited hot saw.



I would have to disagree. 

I do try really hard to disagree without being disagreeable though. 

Have a great evening. :hmm3grin2orange:


----------



## parrisw (Dec 29, 2011)

jropo said:


> Well I couldn't resist. I saw that this was were all the cool kids were hanging out and just read the 32 pages to get caught up. Very interesting! I think is safe to say that a pop-up would be more of pita than what its worth, unless its for a unlimited hot saw.



Not really. Pop-up are actually pretty easy to accomplish, and do serve a good purpose.


----------



## komatsuvarna (Dec 29, 2011)

How bout this pop up?


----------



## parrisw (Dec 29, 2011)

What about a pop-down piston?


----------



## komatsuvarna (Dec 29, 2011)

parrisw said:


> What about a pop-down piston?



With a super long spark plug??? :hmm3grin2orange:


----------



## edisto (Dec 29, 2011)

Will you guys stop posting, so I can get caught up!

I'm still way back at Will's squish job...


----------



## HEAVY FUEL (Dec 29, 2011)

*What's the best kind of oil to use with a Pop-up??????*

:hmm3grin2orange:


----------



## parrisw (Dec 29, 2011)

komatsuvarna said:


> With a super long spark plug??? :hmm3grin2orange:



YAAAAA, now your thinking. 



edisto said:


> Will you guys stop posting, so I can get caught up!
> 
> I'm still way back at Will's squish job...



LOL, hurry up and read.



HEAVY FUEL said:


> :hmm3grin2orange:



LOL LOL LOL 

I've seen some pretty amazing things posted on this site to increase compression. some things I'd never try!! LOL


----------



## tree monkey (Dec 29, 2011)

i remember a guy that drilled a hole in the top of the cylinder, and put a big ol bolt in it to make the chamber smaller


----------



## parrisw (Dec 29, 2011)

tree monkey said:


> i remember a guy that drilled a hole in the top of the cylinder, and put a big ol bolt in it to make the chamber smaller



LOL, that's exactly the one I was thinking of Scott. I thought WTF?????????? I've even seen a pic of a JB welded combustion chamber.


----------



## jropo (Dec 29, 2011)

Just the fact that if you ever have to change out the pistion you need another pop-up is enough to turn me off to the idea.
Cutting the squish band like your doing w/ the 390 seems to me the best long term solution. Provided that you have a lathe. A welder is more accessable but, I like the idea of just putting in a new oem pistion in properly machined bore, rather than every time you fire the saw you wonder if you welds are going to hold. I have seen what loose metal does to a cyl. wall/crank case not pretty!
Dome's on the other hand I still don't see how you could gain any? Seems to me thats a good way to take some comp. out ,but I'm still learning.
If I would have a pop-up it would be a "taller" piston turned down, so if in the future my Son frys the piston when I'm 85 an oem can take its place w/ a little loss in power.


----------



## komatsuvarna (Dec 29, 2011)

jropo said:


> Just the fact that if you ever have to change out the pistion you need another pop-up is enough to turn me off to the idea.
> Cutting the squish band like your doing w/ the 390 seems to me the best long term solution. Provided that you have a lathe. A welder is more accessable but, I like the idea of just putting in a new oem pistion in properly machined bore, rather than every time you fire the saw you wonder if you welds are going to hold. I have seen what loose metal does to a cyl. wall/crank case not pretty!
> Dome's on the other hand I still don't see how you could gain any? Seems to me thats a good way to take some comp. out ,but I'm still learning.
> If I would have a pop-up it would be a "taller" piston turned down, so if in the future my Son frys the piston when I'm 85 an oem can take its place w/ a little loss in power.



You have to drop the cylinder with a popup, or it will have less cranking pressure.


----------



## parrisw (Dec 29, 2011)

jropo said:


> Just the fact that if you ever have to change out the pistion you need another pop-up is enough to turn me off to the idea.
> Cutting the squish band like your doing w/ the 390 seems to me the best long term solution. Provided that you have a lathe. A welder is more accessable but, I like the idea of just putting in a new oem pistion in properly machined bore, rather than every time you fire the saw you wonder if you welds are going to hold. I have seen what loose metal does to a cyl. wall/crank case not pretty!
> Dome's on the other hand I still don't see how you could gain any? Seems to me thats a good way to take some comp. out ,but I'm still learning.
> If I would have a pop-up it would be a "taller" piston turned down, so if in the future my Son frys the piston when I'm 85 an oem can take its place w/ a little loss in power.



Machining the squish is definitely the way to go. I don't know why I've waited so long to try it, but pop-up definitely have their place.


----------



## parrisw (Dec 29, 2011)

komatsuvarna said:


> You have to drop the cylinder with a popup, or it will have less cranking pressure.



?? 

Unless you do a piston swap with a higher deck height, machine it to a popup and your good to go without dropping the cyl. I think that's what he was talking about.


----------



## stihl038x2 (Dec 29, 2011)

komatsuvarna said:


> You have to drop the cylinder with a popup, or it will have less cranking pressure.



If you use a "taller" piston you don't have to drop the jug. 

Steve


----------



## husq2100 (Dec 29, 2011)

or weld ontop of the stock piston and turn that into a pop-up...........


----------



## parrisw (Dec 29, 2011)

husq2100 said:


> or weld ontop of the stock piston and turn that into a pop-up...........



Ya many ways to do things. But welding, you gain piston weight.


----------



## stihl038x2 (Dec 29, 2011)

parrisw said:


> ??
> 
> Unless you do a piston swap with a higher deck height, machine it to a popup and your good to go without dropping the cyl. I think that's what he was talking about.



Speedy fingers !!

Steve


----------



## jropo (Dec 29, 2011)

I'm sure they do! 
I'm sure they really make some power but....just don't like the idea.
Maybe I'll try one on one of my play saws.


----------



## komatsuvarna (Dec 29, 2011)

parrisw said:


> ??
> 
> Unless you do a piston swap with a higher deck height, machine it to a popup and your good to go without dropping the cyl. I think that's what he was talking about.



Maybe Im cornfused with what hes trying to say.

If ya have a saw with say .020 squish, and machine a .030 popup and just put it back together without droping the cylinder back down to .020 squish, you've gained nothing.


----------



## jropo (Dec 29, 2011)

parrisw said:


> ??
> 
> Unless you do a piston swap with a higher deck height, machine it to a popup and your good to go without dropping the cyl. I think that's what he was talking about.



yup


----------



## komatsuvarna (Dec 29, 2011)

stihl038x2 said:


> If you use a "taller" piston you don't have to drop the jug.
> 
> Steve



Right.


----------



## komatsuvarna (Dec 29, 2011)

Ok ok, I mis understood! had to go back and read, Got a little trigger happy. :smile2:

Ill shut up and drink the rest of my beer now!


----------



## jropo (Dec 29, 2011)

But the tricky part is finding a piston the same size but w/ a taller wrist pin to crown height.


----------



## MacLaren (Dec 29, 2011)

Before I got the 660 back from Scott i wandered how well it would perform. Ive ran some fantastic saws with the pop up piston's. So needless to say I was more than surprised at just how strong the 660 turned out. I think both Will and Brad are in for a real treat. Seems all three of us Will, Brad and myself will have 390XP's with the combustion chamber port here shortly. I'll post up some vids of mine as soon as I get her back. I plan on sendin her out either tomorrow or next week.


----------



## parrisw (Dec 29, 2011)

stihl038x2 said:


> Speedy fingers !!
> 
> Steve



:msp_tongue:



komatsuvarna said:


> Maybe Im cornfused with what hes trying to say.
> 
> If ya have a saw with say .020 squish, and machine a .030 popup and just put it back together without droping the cylinder back down to .020 squish, you've gained nothing.



Exactly right!



jropo said:


> But the tricky part is finding a piston the same size but w/ a taller wrist pin to crown height.



Yup. Just do a little search. Many piston swaps are available to do. 

272 in a 372BB
064 in a 460
2101 in a 395

the list goes on I'm sure.


----------



## jropo (Dec 29, 2011)

I would like to see a LONG TERM TEST of a pop-up.


----------



## stihl038x2 (Dec 29, 2011)

jropo said:


> But the tricky part is finding a piston the same size but w/ a taller wrist pin to crown height.



Yeah, that is the tricky part. Is there a "sticky" on piston info. anywhere ???
Maybe someone like Eric or Brad (or any other builder for hire), could start one as they probably have had more different pistons in their hands than most. 
Steve


----------



## stihl038x2 (Dec 29, 2011)

parrisw said:


> :msp_tongue:
> 
> 
> 
> ...



Geeze man............. did you major in typing in school ?????????????

Steve


----------



## parrisw (Dec 29, 2011)

jropo said:


> I would like to see a LONG TERM TEST of a pop-up.



Nothing to worry about for longevity at all. Its just if you smoke a piston, its easier to put back in a stock one, instead of machining a popup again.


----------



## parrisw (Dec 29, 2011)

stihl038x2 said:


> Geeze man............. did you major in typing in school ?????????????
> 
> Steve



LOL. I did take typing class in Grade 8. Best thing I ever did in Highschool Its a great skill actually.


----------



## blsnelling (Dec 29, 2011)

stihl038x2 said:


> Yeah, that is the tricky part. Is there a "sticky" on piston info. anywhere ???
> Maybe someone like Eric or Brad (or any other builder for hire), could start one as they probably have had more different pistons in their hands than most.
> Steve



Jacob J is a walking cross reference manual for piston interchangeability! The guy amazes me.


----------



## jropo (Dec 29, 2011)

parrisw said:


> Nothing to worry about for longevity at all. Its just if you smoke a piston, its easier to put back in a stock one, instead of machining a popup again.



Ya thats with the cut down pop-up I mentioned, but w/ the welded pop-up is what I'd like to see the long term test on.


----------



## parrisw (Dec 29, 2011)

blsnelling said:


> Jacob J is a walking cross reference manual for piston interchangeability! The guy amazes me.



He is. His brain must be full.



jropo said:


> Ya thats with the cut down pop-up I mentioned, but w/ the welded pop-up is what I'd like to see the long term test on.



Welded properly, I wouldn't worry.

TW did some testing a while back on this very subject, had some good findings.

Welded popup is last resort.


----------



## jropo (Dec 29, 2011)

The crappy thing is I had full access to a lathe for the past 15yrs. and only used it about 5 times.


----------



## parrisw (Dec 29, 2011)

jropo said:


> The crappy thing is I had full access to a lathe for the past 15yrs. and only used it about 5 times.



Well, get with it.


----------



## komatsuvarna (Dec 29, 2011)

jropo said:


> Ya thats with the cut down pop-up I mentioned, but w/ the welded pop-up is what I'd like to see the long term test on.



In my little bit of expierence with a welded popup, you lose some spool up time, lose maybe a little top end RPMs, and gain maybe a little torque....and I think its harder on the bottom end with the extra reciprocating mass. JMO again.


----------



## parrisw (Dec 29, 2011)

komatsuvarna said:


> In my little bit of expierence with a welded popup, you lose some spool up time, lose maybe a little top end RPMs, and gain maybe a little torque....and I think its harder on the bottom end with the extra reciprocating mass. JMO again.



Last resort. I've never done it.


----------



## jropo (Dec 29, 2011)

parrisw said:


> Well, get with it.



I showed all my cards and don't have that job any more thus me reading 32 pages of a thread.
But your making think about getting back into it. I do miss it from time to time, but have grown ill with all the bs that goes with it.
Its kill or be killed around here! (Bad times)
Im offically on the look out for a lathe now!


----------



## parrisw (Dec 29, 2011)

jropo said:


> I showed all my cards and don't have that job any more thus me reading 32 pages of a thread.
> But your making think about getting back into it. I do miss it from time to time, but have grown ill with all the bs that goes with it.
> Its kill or be killed around here! (Bad times)
> Im offically on the look out for a lathe now!



Cool. Just don't be in a rush, the deal will come to you.


----------



## jropo (Dec 29, 2011)

seems like the time to buy is now the market is flooded w/ this stuff.
everybody is shutting down
Buyer market IF you have money left.


----------



## MacLaren (Dec 29, 2011)

jropo said:


> seems like the time to buy is now the market is flooded w/ this stuff.
> everybody is shutting down
> Buyer market IF you have money left.



I would imagine your right. As bad as times are/have been it would seem so. But Will gave some very good advice IMO.....


----------



## parrisw (Dec 29, 2011)

jropo said:


> seems like the time to buy is now the market is flooded w/ this stuff.
> everybody is shutting down
> Buyer market IF you have money left.



Yes it is. Around here not so much.


----------



## jropo (Dec 29, 2011)

tree monkey said:


> i remember a guy that drilled a hole in the top of the cylinder, and put a big ol bolt in it to make the chamber smaller



This combined w/ a GOOD weld might work as a last resort. The weld will hold the bolt, bolt will hold the weld, but thats 3 different metals that have to get along in a very unpleasant envrioment.

Any one every try to use a clay form to make the shape of the pop-up to mirror the dome in the top of the cyl.?


----------



## stihl038x2 (Dec 29, 2011)

blsnelling said:


> Jacob J is a walking cross reference manual for piston interchangeability! The guy amazes me.



Well somebody should recruit him to do a thread/sticky for the archives :cool2:

Steve


----------



## parrisw (Dec 29, 2011)

jropo said:


> This combined w/ a GOOD weld might work as a last resort. The weld will hold the bolt, bolt will hold the weld, but thats 3 different metals that have to get along in a very unpleasant envrioment.
> 
> Any one every try to use a clay form to make the shape of the pop-up to mirror the dome in the top of the cyl.?



Kinda like a Hemi?


----------



## parrisw (Dec 29, 2011)

stihl038x2 said:


> Well somebody should recruit him to do a thread/sticky for the archives :cool2:
> 
> Steve



The info is out there, just not all in one spot. 

a couple more. 

460bb in makia BB 

288 in a makita BB

288 in a 066

266 in a 372

Most are not direct swaps.

The possibilities are endless, even in the pin dia is wrong that can be taken care of with a set of these.


----------



## jropo (Dec 29, 2011)

MacLaren said:


> I would imagine your right. As bad as times are/have been it would seem so. But Will gave some very good advice IMO.....



Yes he did!
It's not going to be any time soon!
I wait till one finds me, but now I'll "see it".
I'd like a new one so I know what I'm getting, I don't need another "project"!
But that is just not going to happin right now. 
Besides I'd rather support one of the great builders on this site, that I have learned too much from!


----------



## parrisw (Dec 29, 2011)

jropo said:


> Yes he did!
> It's not going to be any time soon!
> I wait till one finds me, but now I'll "see it".
> I'd like a new one so I know what I'm getting, I don't need another "project"!
> ...



Do not count out old lathes, they are way better then some of the new crap that floods this market. I have and 50's Hercus, which is exactly the same as a old South Bend Model A, heavy cast iron beast, heavy is good when it comes to machine tools.


----------



## jropo (Dec 29, 2011)

parrisw said:


> Kinda like a Hemi?



I never seen inside a Hemi, I know they have a domed head but the piston I don't know.
Make squish at the dome, index the plug?


----------



## parrisw (Dec 29, 2011)

jropo said:


> I never seen inside a Hemi, I know they have a domed head but the piston I don't know.
> Make squish at the dome, index the plug?



I believe they were dome piston, with dome combustion chamber, opposed valves, unlike chevy, ford, where the valves sat side by side. You know your looking at a hemi due to the size of the cyl heads.


----------



## jropo (Dec 29, 2011)

parrisw said:


> Do not count out old lathes, they are way better then some of the new crap that floods this market. I have and 50's Hercus, which is exactly the same as a old South Bend Model A, heavy cast iron beast, heavy is good when it comes to machine tools.



We had a Bridgeport. OOOOOOLLD but did every thing we needed it to do. Most work was done on the HAAS'S, Kingsburys, Mazaks, or the Waterjet.


----------



## jropo (Dec 29, 2011)

parrisw said:


> I believe they were dome piston, with dome combustion chamber, opposed valves, unlike chevy, ford, where the valves sat side by side. You know your looking at a hemi due to the size of the cyl heads.



Ok
Didn't Ford come out w/ a Hemi head design back in the hay days.
Aren't the 4.6 ford mod. motor heads the same size as the old Mopar Hemi.


----------



## parrisw (Dec 29, 2011)

jropo said:


> Ok
> Didn't Ford come out w/ a Hemi head design back in the hay days.
> Aren't the 4.6 ford mod. motor heads the same size as the old Mopar Hemi.



Not 100% sure. 

The old hemis are huge, 4.6's no.


----------



## jropo (Dec 30, 2011)

parrisw said:


> Not 100% sure.
> 
> The old hemis are huge, 4.6's no.



Maybe it was the 5.4's
My buddies dad has a 426 in his 32' Ford.

So do you think it would work?
It has to take some nerve to drill a hole in a piston!


----------



## parrisw (Dec 30, 2011)

jropo said:


> Maybe it was the 5.4's
> My buddies dad has a 426 in his 32' Ford.
> 
> So do you think it would work?
> It has to take some nerve to drill a hole in a piston!



Sorry? what was the question? LOL.


----------



## jropo (Dec 30, 2011)

Sorry got a little off topic.


This combined w/ a GOOD weld might work as a last resort. The weld will hold the bolt, bolt will hold the weld, but thats 3 different metals that have to get along in a very unpleasant envrioment.

Any one every try to use a clay form to make the shape of the pop-up to mirror the dome in the top of the cyl.?


----------



## tree monkey (Dec 30, 2011)

jropo said:


> Sorry got a little off topic.
> 
> 
> This combined w/ a GOOD weld might work as a last resort. The weld will hold the bolt, bolt will hold the weld, but thats 3 different metals that have to get along in a very unpleasant envrioment.
> ...



yes


----------



## jropo (Dec 30, 2011)

Did it work? How well? Does it still work?


----------



## tree monkey (Dec 30, 2011)

t won't spend the time to do it again. yes it works.


----------



## edisto (Dec 30, 2011)

stihl038x2 said:


> Yeah, that is the tricky part. Is there a "sticky" on piston info. anywhere ???
> Maybe someone like Eric or Brad (or any other builder for hire), could start one as they probably have had more different pistons in their hands than most.
> Steve



Awhile back, I started a spreadsheet using the specs Bailey's gives for the pistons they sell. The meteor pistons are fully described. It kind of got to the bottom of a pretty big pile, but I'll get back after it when things clear up a little.


----------



## ECsaws (Dec 30, 2011)

komatsuvarna said:


> In my little bit of expierence with a welded popup, you lose some spool up time, lose maybe a little top end RPMs, and gain maybe a little torque....and I think its harder on the bottom end with the extra reciprocating mass. JMO again.



I have built a couple saws with welded pistons (ginkized), they worked good for the purpose they where intended for didnt notice any lack of RPM or spool up time but i'm sure that closely relates to just how much PSI you make.

Ive pretty much tried it all from machined -welded, pop-ups , to domes... once had a guy tell be he made a custom chamber and actually bolted it to the cly head over the existing chamber... this thread just proves there are more than one way to skin a beaver . Joe smoze may think his ways better than yours or mine , dosnt really mean it is.. stick with what works for you , everyone has a little differnt porting style and the whole package has to work together !
For "Me" for now I'll just stick to the way i'm doing it at the present time.. the only better way I have found is a 2 peace head and that another whole subject.


----------



## 24d (Dec 30, 2011)

jropo said:


> Didn't Ford come out w/ a Hemi head design back in the hay days.


Yes, 427 sohc "Cammer" install a 428 crank and it became a 454. Nice looking motor,


----------



## naturelover (Dec 30, 2011)

Factory Pop up!!! :biggrin:






Sadly, it's only pulling 60psi, cylinder looks good with no scratches, guess the rings are worn out or something, but mainly just had it for a spare.

Pretty neat though, recessed head and everything, shoulda got a picture of it...


----------



## tree monkey (Dec 30, 2011)

parrisw said:


> I've wondered too. I'm pretty certain they both work in 372's, I've tried with and without and they seem to run better with them.



sounds like you done this before and now your going to do it again?


----------



## jropo (Dec 30, 2011)

naturelover said:


> Factory Pop up!!! :biggrin:
> 
> 
> 
> ...



Thats cool! What is it?


----------



## parrisw (Dec 30, 2011)

tree monkey said:


> sounds like you done this before and now your going to do it again?



?? I'm not following what your putting down?


----------



## tree monkey (Dec 30, 2011)

parrisw said:


> Here is a 2 stroke piston, what say you on flow across the piston with this.



lol what were you thinking with this? compleatly different engine


----------



## rms61moparman (Dec 30, 2011)

Well, I'm no machinist.
And I'm no saw builder.
BUT my 372 has a pretty good sized pop-up machined right there on top of the old slug.
It runs ok for a guy who doesn't know any better!:hmm3grin2orange:


Mike


----------



## parrisw (Dec 30, 2011)

tree monkey said:


> lol what were you thinking with this? compleatly different engine



WTF now dude? You trying to start chit again? You don't think I know WTF its from? I posted it for sake of a discussion.


----------



## naturelover (Dec 30, 2011)

That is an old 5hp Sea King two stroke outboard motor. :msp_thumbup:

60psi is the compression service limit. Was mainly saving it for parts, but might just have to see if I can fix it up.

I had a 5hp twin at one point (think it was a Sea King too), but one of the coils was shot. It ran (badly) with just the one cylinder firing though, the other coils insulation had broken down and was grounding to the engine. Thinkin I should have kept that one though.


----------



## Hedgerow (Dec 30, 2011)

tree monkey said:


> lol what were you thinking with this? compleatly different engine



Cross scavenging set up??? Looks like a marine engine...:msp_confused:


----------



## parrisw (Dec 30, 2011)

Hedgerow said:


> Cross scavenging set up??? Looks like a marine engine...:msp_confused:



Yes it is.


----------



## pioneerguy600 (Dec 30, 2011)

Hedgerow said:


> Cross scavenging set up??? Looks like a marine engine...:msp_confused:



I have chainsaws with pistons like this one in them, they are old designs but they were once used in chainsaws.


----------



## jropo (Dec 30, 2011)

naturelover said:


> That is an old 5hp Sea King two stroke outboard motor. :msp_thumbup:
> 
> 60psi is the compression service limit. Was mainly saving it for parts, but might just have to see if I can fix it up.
> 
> I had a 5hp twin at one point (think it was a Sea King too), but one of the coils was shot. It ran (badly) with just the one cylinder firing though, the other coils insulation had broken down and was grounding to the engine. Thinkin I should have kept that one though.



Thats neat!
5hp. twin? all that 60psi must of been a bear to pull over!!!


----------



## Tzed250 (Dec 30, 2011)

parrisw said:


> Here is a 2 stroke piston, what say you on flow across the piston with this.




That is a piston from a cross scavenged engine. The development of Schneürle porting made the cross scavenged engine obsolete for most high performance applications.


----------



## Metals406 (Dec 30, 2011)

parrisw said:


> WTF now dude? You trying to start chit again? You don't think I know WTF its from? I posted it for sake of a discussion.



He's just razzing ya cuz you're so handsome!


----------



## Hedgerow (Dec 30, 2011)

parrisw said:


> ?? I'm not following what your putting down?



I think he was getting at the point tha you've been down the pop up road, and then found out how to raise the compression to the desired level without one... And is now wondering why you would ever want to go back...
But I've been wrong before...
And will be again...
:hmm3grin2orange:


----------



## parrisw (Dec 30, 2011)

Tzed250 said:


> That is a piston from a cross scavenged engine. The development of Schneürle porting made the cross scavenged engine obsolete for most high performance applications.



I know what its from. Don't know why people have to keep telling me?????? 

Actually the reason I posted it was because I am retrofitting it into a 372.


----------



## parrisw (Dec 30, 2011)

Metals406 said:


> He's just razzing ya cuz you're so handsome!



LOL, thanks Nate, now that makes the most sense of all. So your saying he's attracted to me? 



Hedgerow said:


> I think he was getting at the point tha you've been down the pop up road, and then found out how to raise the compression to the desired level without one... And is now wondering why you would ever want to go back...
> But I've been wrong before...
> And will be again...
> :hmm3grin2orange:



Ok, that makes sense. For the record, I didn't just find out about cutting squish bands. I never said I was going back to popups or staying with doing cutting squish bands. I simply said what I thought about how a 372 ran with them that's all. 

GEEEEEEEEEEEEZZZZZZZZZZZZEEEEEEEEEE, makes me feel like I'm talking to my wife. People need to not read too far into things, just take it for exactly what I said.


----------



## parrisw (Dec 30, 2011)

parrisw said:


> I've wondered too. I'm pretty certain they both work in 372's, I've tried with and without and they seem to run better with them.



This is what I said. Doesn't mean anything but that I think 372's run well with them.


----------



## Tzed250 (Dec 30, 2011)

parrisw said:


> I know what its from. Don't know why people have to keep telling me??????
> 
> Actually the reason I posted it was because I am retrofitting it into a 372.



LOL!! I know that you know what it is Will, the post was for the benefit of those that don't.


----------



## RiverRat2 (Dec 30, 2011)

Kick back and have a beer,,, or a scotch,,, or mayber some good Vodka!!!!

Im havin a Pennsylvania Dutch Egg nog on Ice with coffee!!! it has Rum, blended whiskey, Probably Canadian,,, (I always knew you guys are good for somethin) and brandy!!!!!

It's like a Latte' with a kick!!!!!


----------



## Andyshine77 (Dec 30, 2011)

tree monkey said:


> btw i don't think this topic would have came up if i had not said that i cut the squish in pauls 660 and the 372 build off saws.



Sorry but no, cutting the squish band is nothing new. This thread is about what really works, and what some thought worked, but in reality maybe doesn't, or at least not in every application. 



ECsaws said:


> Andy have you used that new piston yet ?
> I may try to locate one and give it a whirl in the stumpy 7900 build. piston looks interesting to say the least...:wink2:



I've yet to see these new pistons in person, From what I've been told it's part of the new 7900.


----------



## Tzed250 (Dec 30, 2011)

RiverRat2 said:


> Kick back and have a beer,,, or a scotch,,, or mayber some good Vodka!!!!



Mmmmmm...single malt....


----------



## Hedgerow (Dec 30, 2011)

parrisw said:


> This is what I said. Doesn't mean anything but that I think 372's run well with them.



I wonder if that's cause they're relatively low on compression and have so much space up top...??? I just measured the squish on my 372 without a base gasket, and it's still got .030 squish...


----------



## parrisw (Dec 30, 2011)

Tzed250 said:


> LOL!! I know that you know what it is Will, the post was for the benefit of those that don't.



LOL, sorry John, I guess I'm a little on edge. Mr Monkey know how to push my buttons I guess.



RiverRat2 said:


> Kick back and have a beer,,, or a scotch,,, or mayber some good Vodka!!!!



Just had a rum and egg nogg. 

I think I need to unsubscribe, this thread is bad for my health!!!!!!


----------



## parrisw (Dec 30, 2011)

Hedgerow said:


> I wonder if that's cause they're relatively low on compression and have so much space up top...??? I just measured the squish on my 372 without a base gasket, and it's still got .030 squish...



Ya, all 372's I've done are well over .040" squish. As soon as my 390 is done, I'm doing up a 372 with no popup just to see.


----------



## Metals406 (Dec 30, 2011)

parrisw said:


> LOL, thanks Nate, now that makes the most sense of all. So your saying he's attracted to me?



He's certainly attracted to poking you in the eye with a stick! oke:

:hmm3grin2orange:


----------



## Metals406 (Dec 30, 2011)

Tzed250 said:


> Mmmmmm...single malt....



CHA-CHING! 

They definitely don't give it away. $$$$$$$$


----------



## parrisw (Dec 30, 2011)

Metals406 said:


> He's certainly attracted to poking you in the eye with a stick! oke:
> 
> :hmm3grin2orange:



LOL, ya. Dang this INTERNET lack of communication!!! I'm super bad at work for giving people a hard time.


----------



## Andyshine77 (Dec 30, 2011)

jropo said:


> Well I couldn't resist. I saw that this was were all the cool kids were hanging out and just read the 32 pages to get caught up. Very interesting! I think is safe to say that a pop-up would be more of pita than what its worth, unless its for a unlimited hot saw.



Yes and no. I've seen pop ups make one saw stronger and the other slower.


----------



## tree monkey (Dec 30, 2011)

parrisw said:


> LOL, sorry John, I guess I'm a little on edge. Mr Monkey know how to push my buttons I guess.
> 
> 
> 
> ...



i'm sorry you make it so easy that i can't help myself:biggrin:


----------



## parrisw (Dec 30, 2011)

tree monkey said:


> i'm sorry you make it so easy that i can't help myself:biggrin:



Argg, fair enough.


----------



## jropo (Dec 30, 2011)

Andyshine77 said:


> Yes and no. I've seen pop ups make one saw stronger and the other slower.



Well now I'm on the fence!
I want to try one ,but its not going to be in anything I'm gonna give a hoot about!
Once totally sold a "ized" 346 basket case to follow as a toy only.
But for how much I'm even cutting now days might as well just go get a WWWWWILD THANG!!!!!!:hmm3grin2orange:


----------



## pops21 (Dec 30, 2011)

Pre-heating the piston before welding the popup might/should prevent warping. Right? I've alwayse wondered if scoloping (sp) the crank would have any advantage. I know some have said that its not going threw a bath of oil then no it would not. Another thing that I've thought about is knife edging the connecting rod.


----------



## jropo (Dec 30, 2011)

pops21 said:


> Pre-heating the piston before welding the popup might/should prevent warping. Right? I've alwayse wondered if scoloping (sp) the crank would have any advantage. I know some have said that its not going threw a bath of oil then no it would not. Another thing that I've thought about is knife edging the connecting rod.



I would pre-heat. 
The only gains I could see w/ the crank or con-rods is to smooth them out.(less air drag?)
But then you'd have to rebalance them?


----------



## Tzed250 (Dec 30, 2011)

pops21 said:


> I've alwayse wondered if scoloping (sp) the crank would have any advantage. I know some have said that its not going threw a bath of oil then no it would not. Another thing that I've thought about is knife edging the connecting rod.




Tried. No gain.


----------



## RiverRat2 (Dec 30, 2011)

Tzed250 said:


> Mmmmmm...single malt....



LOLOL!!! Glenfiddich Special Reserve 12 yr. old???

Or Glenmorangie,,, is very good too!!!


----------



## Tzed250 (Dec 30, 2011)

RiverRat2 said:


> LOLOL!!! Glenfiddich Special Reserve 12 yr. old???
> 
> Or Glenmorangie,,, is very good too!!!



Now you're talking!!!


----------



## pops21 (Dec 30, 2011)

Tzed250 said:


> Tried. No gain.



Hmmmm Well so much for my thinking.


----------



## rms61moparman (Dec 30, 2011)

pops21 said:


> Pre-heating the piston before welding the popup might/should prevent warping. Right? *I've alwayse wondered if scoloping (sp) the crank would have any advantage.* I know some have said that its not going threw a bath of oil then no it would not. *Another thing that I've thought about is knife edging the connecting rod*.





Well my question would be..."To what end"?

In a work saw, I believe the benefits will be slight and the trouble would be immense.
In a full blown race saw......maybe!


Mike


----------



## Andyshine77 (Dec 30, 2011)

jropo said:


> Well now I'm on the fence!
> I want to try one ,but its not going to be in anything I'm gonna give a hoot about!
> Once totally sold a "ized" 346 basket case to follow as a toy only.
> But for how much I'm even cutting now days might as well just go get a WWWWWILD THANG!!!!!!:hmm3grin2orange:



Well I'll reiterate that in my experience, saws with lower compression benefit the most, if you already have 160psi 10 to 20 extra psi likely isn't going to do much IMHO.


----------



## jropo (Dec 30, 2011)

Andyshine77 said:


> Well I'll reiterate that in my experience, saws with lower compression benefit the most, if you already have 160psi 10 to 20 extra psi likely isn't really going to do much IMHO.



Ya but 30psi + 160psi = :hmm3grin2orange:


----------



## edisto (Dec 30, 2011)

parrisw said:


> Actually the reason I posted it was because I am retrofitting it into a 372.



You'll see an easy 15% gain from the increase in transfer velocity if you put it in upside down.


----------



## parrisw (Dec 31, 2011)

edisto said:


> You'll see an easy 15% gain from the increase in transfer velocity if you put it in upside down.



Sweet! Thanks for the heads up!


----------



## edisto (Dec 31, 2011)

Andyshine77 said:


> Well I'll reiterate that in my experience, saws with lower compression benefit the most, if you already have 160psi 10 to 20 extra psi likely isn't going to do much IMHO.



Might decrease charge density by getting the piston hotter...


----------



## mdavlee (Dec 31, 2011)

Some of the 372s won't make 150 lbs when broken in. Usually you can leave out the base gasket and get it down to the mid .020". I've not done any popups in anything but the 50mm 372 jugs. The 2 that i've had terry turn were real close to 200. I did have a 390 with the squish tightened up and it seemed to be a little stronger than the others I had with 155 lbs of compression. I would venture to guess they would benefit more than say a 394 that has 175 to start with also.


----------



## jropo (Dec 31, 2011)

"Some of the 372s won't make 150 lbs when broken in."



Really? Thats crazy I have a Crapsman that makes 150 stock!
I always thought 150 was resectable since my sleds only make 120.


----------



## Andyshine77 (Dec 31, 2011)

Mike's really good running and well broken in 372 had 145psi, the 372's don't normally make much compression stock.


----------



## parrisw (Dec 31, 2011)

For some reason 372's don't need excessive comp to run well. Mine rips at 160, its probably a little more now though.


----------



## rms61moparman (Dec 31, 2011)

Andyshine77 said:


> Mike's really good running and well broken in 372 had 145psi, the 372's don't normally make much compression stock.




It makes a little bit more than that now though.

Not a LOT more but a little.


Mike


----------



## jropo (Dec 31, 2011)

parrisw said:


> For some reason 372's don't need excessive comp to run well. Mine rips at 160, its probably a little more now though.



What is the highest comp. seen in a 372?
Maybe too much comp. might start hurting the crank/bearings.


----------



## parrisw (Dec 31, 2011)

jropo said:


> What is the highest comp. seen in a 372?
> Maybe too much comp. might start hurting the crank/bearings.



I don't know, but would imagine for a race built 372 would be pretty high.


----------



## blsnelling (Dec 31, 2011)

IIRC, my 372 has something like 190 PSI. I'd have to check it again to be sure.

<iframe width="853" height="480" src="http://www.youtube.com/embed/bCxFTxINYVY?rel=0" frameborder="0" allowfullscreen></iframe>


----------



## jropo (Dec 31, 2011)

Nice!!!
Pop-up?


----------



## blsnelling (Dec 31, 2011)

jropo said:


> Nice!!!
> Pop-up?



Yes.


----------



## jropo (Dec 31, 2011)

blsnelling said:


> Yes.



Nice!

How many hours/tanks?
How offten do you use it? 
Firewood/Logging?


----------



## rms61moparman (Dec 31, 2011)

That sure is a great running 372 Brad.
Mine only has 175 or so.


Mike


----------



## blsnelling (Dec 31, 2011)

rms61moparman said:


> That sure is a great running 372 Brad.
> Mine only has 175 or so.
> 
> 
> Mike



We'll have to run 'em some time. I have a hunch yours will hand it it's rear end!


----------



## jropo (Dec 31, 2011)

rms61moparman said:


> That sure is a great running 372 Brad.
> Mine only has 175 or so.
> 
> 
> Mike



Does yours have a pop-up?


----------



## rms61moparman (Dec 31, 2011)

jropo said:


> Does yours have a pop-up?



Absolutely!!!


Mike


----------



## rms61moparman (Dec 31, 2011)

blsnelling said:


> We'll have to run 'em some time. I have a hunch yours will hand it it's rear end!




Well now I don't know about that!
I really like mine though.
I intend to have it under the bed in my nursing home.....someday!!!


Mike


----------



## jropo (Dec 31, 2011)

rms61moparman said:


> Absolutely!!!
> 
> 
> Mike



Did Brad do it?


----------



## blsnelling (Dec 31, 2011)

Nope. Our buddy Nik did them.


----------



## jropo (Dec 31, 2011)

You guys really make me want to trear a saw down!!!!
Nik? Sponser?


----------



## blsnelling (Dec 31, 2011)

Nik is FATGUY. He is not a sponsor. He's a good, no, a great friend, of ours.


----------



## parrisw (Dec 31, 2011)

I'm guessing Nik did the machine work.


----------



## jropo (Dec 31, 2011)

blsnelling said:


> Nik is FATGUY. He is not a sponsor. He's a good, no, a great friend, of ours.



Oh Ok I seen him on here.

Cut or welded?


----------



## jropo (Dec 31, 2011)

Has any one tried a pop-up on a ms170 or a Wild Thang? Just 4 kicks...


----------



## rms61moparman (Dec 31, 2011)

HaHaHa!!!!


Try this.............if it works!





Mike


----------



## rms61moparman (Dec 31, 2011)

Try clicking on that pic.
If it doesn't work I'll try something else.


Mike


----------



## jropo (Dec 31, 2011)

:msp_w00t:

Thats friggn GREAT!!!!
Did you cut or weld the piston?
Pipe!!! Are you kidding me!!!!!
How did you figure out the size of the pipe?
AWESOME!!!!


----------



## rms61moparman (Dec 31, 2011)

jropo said:


> :msp_w00t:
> 
> Thats friggn GREAT!!!!
> Did you cut or weld the piston?
> ...





That's not me there pardner!!!
That is the saw that kicked all our butts in the Wildthing races.
It belongs to Arrowhead.
The pop-up was welded.


Mike


----------



## jropo (Dec 31, 2011)

rms61moparman said:


> That's not me there pardner!!!
> That is the saw that kicked all our butts in the Wildthing races.
> It belongs to Arrowhead.
> The pop-up was welded.
> ...



Looks like I'm tearing down a wild thang!!!
I remember reading about that. I wish I was there!


----------



## jropo (Dec 31, 2011)

Any 170 Pop-ups out there?


----------



## ECsaws (Dec 31, 2011)

Andyshine77 said:


> :
> 
> 
> 
> I've yet to see these new pistons in person, From what I've been told it's part of the new 7900.



I have not had one in my hands yet eather.... buddie from VA has one of the new kits he did some weighing and texted me some pics of the new one, looks interesting .
I have another 7900 headed this way with the new style kit I'm going to port it the same way as the stumpy giveaway saw and see if there are any noticeable differences


----------



## ECsaws (Dec 31, 2011)

parrisw said:


> For some reason 372's don't need excessive comp to run well. Mine rips at 160, its probably a little more now though.



You can defnatly get to much :help: I did one for my self a while back ... cut .070 out of the cly ran it with a stock piston made 220 lbs saw ran good but got hot.. got a hair brain idea to put a 1mm ring wiseco piston in it pulled the static down to200- 210... but the dynamic went thru the roof one long extended cut and she was smok'in  seams like they like around 180-190 on a OEM piston...


----------



## gink595 (Dec 31, 2011)

pops21 said:


> Pre-heating the piston before welding the popup might/should prevent warping. Right?



Wrong! Preheating alone can make it warp if it isn't evenly heated. Preheating works good to draw the moisture out of the base metal and aids in the time it takes to start running a weld. The first ones I welded I grabbed the oven off the wifes counter and hauled it to the shop and warmed a piston up to about 300*, it was a bad idea in hindsight, all the french fry grease contaminated the piston and made it near impossible to tig weld. Aluminum has to be almost completely free of any kind of oil, grease, carbon, oxidation. With the old transformer Sine wave machine I use I can't adjust the balance wave to for a cleaning action so for me if I can't get it clean it is a bear to try and weld.


----------



## sachsmo (Dec 31, 2011)

So what is you guys' thoughts on using a non-windowed piston in a saw that had a windowed piston from the factory?
Have an old 343 chop saw that needs a slug, and the only stock one I can find is um, too rich for my blood.

I like the idea of cutting the squish band, since it reduces chamber volume. Just skimming some off the slug seems a waste.


----------



## showrguy (Dec 31, 2011)

gink595 said:


> Wrong! Preheating alone can make it warp if it isn't evenly heated. Preheating works good to draw the moisture out of the base metal and aids in the time it takes to start running a weld. The first ones I welded I grabbed the oven off the wifes counter and hauled it to the shop and warmed a piston up to about 300*, it was a bad idea in hindsight, all the french fry grease contaminated the piston and made it near impossible to tig weld. Aluminum has to be almost completely free of any kind of oil, grease, carbon, oxidation. With the old transformer Sine wave machine I use I can't adjust the balance wave to for a cleaning action so for me if I can't get it clean it is a bear to try and weld.



hey gink, (or anyone else)
what alloy would be recomended when doing a welded popup ??
if it's in this thread i missed it..


----------



## sachsmo (Dec 31, 2011)

Made one for an old 7-10, don't remember the type wire used.
I used a spool gun with an old mig. Turned out a piece of xx heavy wall black pipe scoshe bigger than the slug.
Did my best imitation of a Dairy Queen cone, and cleaned her up on the lathe.

It was way too big, (had to grind a flame channel for the plug)
Damned thing is a biotch to start, and idles real wonky too.
The thing stumbles a bit from idle, but if you get a few revs, she accelerates like lightning.

I have yet to get the thing to four stroke, she will rev to destruction if I would let it.


----------



## gink595 (Dec 31, 2011)

showrguy said:


> hey gink, (or anyone else)
> what alloy would be recomended when doing a welded popup ??
> if it's in this thread i missed it..



I've used 4043 which is a common aluminum rod and it worked well, I've also used 4047 which has a higher silicon content that I believe would withstand higher combustion temps. It would be neat to see them after some good run time was done to see if one performed better than the other.


----------



## Mastermind (Dec 31, 2011)

jropo said:


> Has any one tried a pop-up on a ms170 or a Wild Thang? Just 4 kicks...



[video=youtube;dFlXTRLohq4]http://www.youtube.com/watch?v=dFlXTRLohq4&feature=g-upl&context=G26ecfc1AUAAAAMgAWAA[/video]


----------



## Outlaw5.0 (Dec 31, 2011)

Another issue with high compression is skinned knuckles. I had one factory jug MS460 at 205 psi and one Big Bore at 200 psi, both were hard to start and kicked back resulting in bleeding knuckles. Seems I have to learn the hard way first.


----------



## Metals406 (Dec 31, 2011)

gink595 said:


> Wrong! Preheating alone can make it warp if it isn't evenly heated. Preheating works good to draw the moisture out of the base metal and aids in the time it takes to start running a weld. The first ones I welded I grabbed the oven off the wifes counter and hauled it to the shop and warmed a piston up to about 300*, it was a bad idea in hindsight, all the french fry grease contaminated the piston and made it near impossible to tig weld. Aluminum has to be almost completely free of any kind of oil, grease, carbon, oxidation. With the old transformer Sine wave machine I use I can't adjust the balance wave to for a cleaning action so for me if I can't get it clean it is a bear to try and weld.



Frank, are you sure it wasn't the Sharpie that contaminated your weld? :biggrin:


----------



## naturelover (Dec 31, 2011)

jropo said:


> Thats neat!
> 5hp. twin? all that 60psi must of been a bear to pull over!!!



lol.

It was unbearable, I almost had to use three fingers!!!

Easy-Start! 

Errr, scratch that, Easy-Pull!


----------



## Metals406 (Dec 31, 2011)

gink595 said:


> I've used 4043 which is a common aluminum rod and it worked well, I've also used 4047 which has a higher silicon content that I believe would withstand higher combustion temps. It would be neat to see them after some good run time was done to see if one performed better than the other.



If I remember right, Brian looked at modern piston casting %'s, and said the 4047 more closely matched the silicon content of the piston.

Like ya say though, don't think it makes a huge difference using either one.


----------



## RiverRat2 (Dec 31, 2011)

parrisw said:


> For some reason 372's don't need excessive comp to run well. Mine rips at 160, its probably a little more now though.



They are just plain ol' "Bad Azzed" 70 CC saws to begin with!!!! Mine is blowin about 175 and it absolutely rips,,,,


----------



## jropo (Dec 31, 2011)

Mastermind said:


> [video=youtube;dFlXTRLohq4]http://www.youtube.com/watch?v=dFlXTRLohq4&feature=g-upl&context=G26ecfc1AUAAAAMgAWAA[/video]



LOL!:msp_ohmy: Thats Great!!!!!
Whats going on w/ the carb situation there!!? 
What all do you have into it?
Is that another "Shoot out Saw"?
AWSOME!!!!


----------



## jropo (Dec 31, 2011)

Outlaw5.0 said:


> Another issue with high compression is skinned knuckles. I had one factory jug MS460 at 205 psi and one Big Bore at 200 psi, both were hard to start and kicked back resulting in bleeding knuckles. Seems I have to learn the hard way first.



Decomp.?


----------



## Mastermind (Dec 31, 2011)

jropo said:


> LOL!:msp_ohmy: Thats Great!!!!!
> Whats going on w/ the carb situation there!!?
> What all do you have into it?
> Is that another "Shoot out Saw"?
> AWSOME!!!!



It has a carb from a XL-12 on it and external transfer ports. It needs a pipe. :msp_thumbup:


----------



## Outlaw5.0 (Dec 31, 2011)

jropo said:


> Decomp.?


That works good warm/hot start, but does not always work on a cold start. Plus trying to get a compression reading on a 200 psi saw is interesting.


----------



## jropo (Dec 31, 2011)

Mastermind said:


> It has a carb from a XL-12 on it and external transfer ports. It needs a pipe. :msp_thumbup:



How did you figure you needed a XL-12 carb.? Bolt on?
External Transfer's? How in the Poulan did you do that? Drill/Tap/weld?
I suppose if you really want to make power you need to move some air! External Trans. will do that!!!! 
I still tring to figure out how much of a pipe per cc,cfm, rpm,ect. is needed w/o a flow bench?


----------



## jropo (Dec 31, 2011)

Outlaw5.0 said:


> That works good warm/hot start, but does not always work on a cold start. Plus trying to get a compression reading on a 200 psi saw is interesting.



I bet!!!!!
I would imagine the bigger the bore the worst it is! (More rotating mass)
Thats has to be hard on the starter dogs, ect. also!!!!!!
I use the Decomp. on my 150psi. 385. (bum shoulder,wrist, well everything) Electric start?!!!!!!!!


----------



## Hedgerow (Dec 31, 2011)

Outlaw5.0 said:


> That works good warm/hot start, but does not always work on a cold start. Plus trying to get a compression reading on a 200 psi saw is interesting.



Ya think??? Like my 372... It works better with two people. One to hold the guage... One to try and break the recoil...


----------



## ECsaws (Dec 31, 2011)

Happy new year !!!!


----------



## ECsaws (Dec 31, 2011)




----------



## edisto (Dec 31, 2011)

Is the flux capacitor OEM?


----------



## Tzed250 (Dec 31, 2011)

Holy crap Eric, that is a bad mother effworder!!!!!!


----------



## Metals406 (Dec 31, 2011)

Pretty sweet Eric!

Do you put a foam filter over that bell mouth when you run, or leave it open?


----------



## gink595 (Dec 31, 2011)

Leave it open!!


----------



## Metals406 (Dec 31, 2011)

gink595 said:


> Leave it open!!



I know it's only a few seconds per run, but wouldn't a guy worry about ingestion?


----------



## tree monkey (Dec 31, 2011)

Metals406 said:


> I know it's only a few seconds per run, but wouldn't a guy worry about ingestion?



dont eat chilly before the race


----------



## gink595 (Dec 31, 2011)

Metals406 said:


> I know it's only a few seconds per run, but wouldn't a guy worry about ingestion?



My 50 has the bell sticking out like that and it does suck a little dust in but I'm not to concerned for what it is being used for.


----------



## Metals406 (Dec 31, 2011)

tree monkey said:


> dont eat chilly before the race



 Yeah, that'd fix it!



gink595 said:


> My 50 has the bell sticking out like that and it does suck a little dust in but I'm not to concerned for what it is being used for.



Hmmm, I'd think more than dust might get sucked in there. . . But I ain't ever ran a fancy racesaw, so I wouldn't know.

What about pulling some ladies pantyhose over it for sex appeal? :wink2:


----------



## gink595 (Jan 1, 2012)

Metals406 said:


> Hmmm, I'd think more than dust might get sucked in there. . .



Good thing the sack is bigger than the carb bore, if you feel the wind I guess you'd better tuck them in :msp_ohmy:


----------



## tree monkey (Jan 1, 2012)

gink595 said:


> Good thing the sack is bigger than the carb bore, if you feel the wind I guess you'd better tuck them in :msp_ohmy:



you could choke the saw and the chicken at the same time.:msp_w00t:


----------



## Metals406 (Jan 1, 2012)

gink595 said:


> Good thing the sack is bigger than the carb bore, if you feel the wind I guess you'd better tuck them in :msp_ohmy:





:hmm3grin2orange::hmm3grin2orange:


----------



## jropo (Jan 1, 2012)

Thats Crazy!!!!!

That would make for a bad day!!!!
Explain that at the E.R.!!!!!


----------



## Andyshine77 (Jan 1, 2012)

jropo said:


> What is the highest comp. seen in a 372?
> Maybe too much comp. might start hurting the crank/bearings.



I've never experienced or seen any bottom end issues with the 372's myself, but it's supposedly a weak spot with the 372. In a true 372 work saw I wouldn't want more than 180psi of compression IMHO.


----------



## jropo (Jan 1, 2012)

Andyshine77 said:


> I've never experienced or seen any bottom end issues with the 372's myself, but it's supposedly a weak spot with the 372. In a true 372 work saw I wouldn't want more than 180psi of compression IMHO.



Thats handy info. right there!


----------



## gink595 (Jan 1, 2012)

Andyshine77 said:


> I've never experienced or seen any bottom end issues with the 372's myself, but it's supposedly a weak spot with the 372. In a true 372 work saw I wouldn't want more than 180psi of compression IMHO.



Based on what actual facts is this opinion being based off of? Just curious if you have any real hard evidence to prove your "IMHO"


----------



## rms61moparman (Jan 1, 2012)

gink595 said:


> Based on what actual facts is this opinion being based off of? Just curious if you have any real hard evidence to prove your "IMHO"





"HO"s don't need actual facts Frank.
That's why they are "HO"s.


Mike


----------



## gink595 (Jan 1, 2012)

rms61moparman said:


> "HO"s don't need actual facts Frank.
> That's why they are "HO"s.
> 
> 
> Mike



OK, just wanted to make sure he wasn't preaching the gospel on hard facts. :hmm3grin2orange:


----------



## Dennis Cahoon (Jan 1, 2012)

ECsaws said:


> Is this one of your "fast" chains.......Woodjunkie?


----------



## Hedgerow (Jan 1, 2012)

Andyshine77 said:


> I've never experienced or seen any bottom end issues with the 372's myself, but it's supposedly a weak spot with the 372. In a true 372 work saw I wouldn't want more than 180psi of compression IMHO.



I got one pushing 200... It's still alive...


----------



## RiverRat2 (Jan 2, 2012)

rms61moparman said:


> "HO"s don't need actual facts Frank.
> That's why they are "HO"s.
> 
> 
> Mike



I don't care what you say,,, that's funny right there Mike,,,, ROFLMAO

Remind me to to tell you the HO Joke @ the next GTG We meet @ I'm thinking the 390XP Build off will be my next one,,,,


----------



## MCW (Jan 5, 2012)

Good thread guys and I unfortunately found it late.
Some very interesting info


----------



## Andyshine77 (Jan 8, 2012)

gink595 said:


> Based on what actual facts is this opinion being based off of? Just curious if you have any real hard evidence to prove your "IMHO"



No hard facts, but I've seen evidence of over heating and detonation on a few pistons, keep in mind poor quality fuel is also a factor. Not every compression gauge will read the same, I've seen as much as 30psi difference between two working gauges, so my gauge could read 170 yours may read 200. A true 200psi is pushing things to far for pump fuel with alcohol. *IMHO*


----------



## sachsmo (Jan 8, 2012)

e85 will take a good bit of squeeze.


----------



## Mastermind (Jan 8, 2012)

Andyshine77 said:


> No hard facts, but I've seen evidence of over heating and detonation on a few pistons, keep in mind poor quality fuel is also a factor. Not every compression gauge will read the same, I've seen as much as 30psi difference between two working gauges, so my gauge could read 170 yours may read 200. A true 200psi is pushing things to far for pump fuel with alcohol. *IMHO*



At the risk of turning this thread into an oil thread I'll throw this out there. If a crappy ethanol laced fuel is being used the use of a good oil is even more important. In the oils I use the ability to mix with alcohol is of the utmost importance.

And yeah, 200psi on crappy fuel is way too much. *IMHO*


----------



## MacLaren (Jan 8, 2012)

Mastermind said:


> At the risk of turning this thread into an oil thread I'll throw this out there. If a crappy ethanol laced fuel is being used the use of a good oil is even more important. In the oils I use the ability to mix with alcohol is of the utmost importance.
> 
> And yeah, 200psi on crappy fuel is way too much. *IMHO*



Im just curious, but why is it important for the oil to be compatible with alcohol? I uusually use 93 ethanol free with Bel-Ray H1R or Klotz Original Techniplate or R-50. Thanks for any 411


----------



## komatsuvarna (Jan 8, 2012)

Hedgerow said:


> I got one pushing 200... It's still alive...



Mine too. :msp_sneaky:


----------



## Mastermind (Jan 8, 2012)

MacLaren said:


> Im just curious, but why is it important for the oil to be compatible with alcohol? I uusually use 93 ethanol free with Bel-Ray H1R or Klotz Original Techniplate or R-50. Thanks for any 411



My thinking is if it will mix with alcohol it will mix with and help displace any water and or other crap that's in the fuel.

I'm using HR1 right now and like it very well.


----------



## MacLaren (Jan 8, 2012)

Mastermind said:


> My thinking is if it will mix with alcohol it will mix with and help displace any water and or other crap that's in the fuel.
> 
> I'm using HR1 right now and like it very well.



Yes. Makes sense. Thanks Randy. Im liking the Bel-Ray H1R a lot myself.:msp_thumbup:


----------



## komatsuvarna (Jan 8, 2012)

Mastermind said:


> My thinking is if it will mix with alcohol it will mix with and help displace any water and or other crap that's in the fuel.
> 
> *I'm using HR1 right now and like it very well.*



Me too! I got about 6 tanks through the 66, pulled the plug yesterday and the piston is still SHINY CLEAN even at 32:1!!! I really like it. Ill post a picture in Mdavlees original thread when I tear it back down for port work.....which may be today .

You tried that K2 yet?


----------



## mdavlee (Jan 8, 2012)

That is good news durand. I was hoping it would burn clean. I'll probably mix 3oz per gallon of it just so it's an even number. Mixing with alcohol is important for a lot of people that have no access to ethanol free pump gas.


----------



## Mastermind (Jan 8, 2012)

komatsuvarna said:


> Me too! I got about 6 tanks through the 66, pulled the plug yesterday and the piston is still SHINY CLEAN even at 32:1!!! I really like it. Ill post a picture in Mdavlees original thread when I tear it back down for port work.....which may be today .
> 
> You tried that K2 yet?



No I'm still using Belray........


----------



## mt.stalker (Jan 8, 2012)

sachsmo said:


> e85 will take a good bit of squeeze.



holy popup :d


----------



## Hedgerow (Jan 8, 2012)

komatsuvarna said:


> Mine too. :msp_sneaky:



Hey Durand, is that your 372?


----------



## komatsuvarna (Jan 8, 2012)

Hedgerow said:


> Hey Durand, is that your 372?



yep


----------



## parrisw (Jan 8, 2012)

komatsuvarna said:


> yep



What did ya do to get that much compression?


----------



## tlandrum (Jan 8, 2012)

my guess is welded pop up


----------



## parrisw (Jan 8, 2012)

tlandrum said:


> my guess is welded pop up



I wonder, I've never got that much comp out of a 372 with standard machining, .030 popup.


----------



## komatsuvarna (Jan 8, 2012)

tlandrum said:


> my guess is welded pop up



Yep correct. Thats with a single ring too. I may tone it down just a hair more...... Its was ~220, and I shaved a little off it.


----------



## parrisw (Jan 8, 2012)

komatsuvarna said:


> Yep correct. Thats with a single ring too. I may tone it down just a hair more...... Its was ~220, and I shaved a little off it.



Do tell? How big? any pics.


----------



## Hedgerow (Jan 8, 2012)

komatsuvarna said:


> yep



I wondered about that... That saw is just nasty... It may be be pushing the envelope... How many hours you got on it as of this week...??? And of course, if you get tired of it you know where it can come live... 
Just sayin...


----------



## Hedgerow (Jan 8, 2012)

parrisw said:


> Do tell? How big? any pics.



Something tells me it was alot more than .030... More like .090...


----------



## komatsuvarna (Jan 8, 2012)

parrisw said:


> Do tell? How big? any pics.



LOL, It started out about .100 to begin with. I ran one tank through it and checked compression and it was ~220. I pulled it back down and cut about .030 off it and it was at 190. Ive ran a lot of fuel through it since then so it should be broke in. I pulled 200 this morning. I had to buy a new gauge, and that was my test saw.

My exhaust is low enough I can throw a flat top back in it and have ~140/150 psi. The welded popup was an expierment.


----------



## komatsuvarna (Jan 8, 2012)

Hedgerow said:


> I wondered about that... That saw is just nasty... It may be be pushing the envelope... How many hours you got on it as of this week...??? And of course, if you get tired of it you know where it can come live...
> Just sayin...



I dunno how many hours, but I've put quite a few gallons through it though. Its fairly strong, But it still won't run with Tlandrum's XPW.







Im gonna have to figure out someway to pull a sneak attack on him.:hmm3grin2orange:


----------



## parrisw (Jan 8, 2012)

komatsuvarna said:


> LOL, It started out about .100 to begin with. I ran one tank through it and checked compression and it was ~220. I pulled it back down and cut about .030 off it and it was at 190. Ive ran a lot of fuel through it since then so it should be broke in. I pulled 200 this morning. I had to buy a new gauge, and that was my test saw.
> 
> My exhaust is low enough I can throw a flat top back in it and have ~140/150 psi. The welded popup was an expierment.



Cool, thanks!



komatsuvarna said:


> I dunno how many hours, but I've put quite a few gallons through it though. Its fairly strong, But it still won't run with Tlandrum's XPW.
> 
> 
> 
> ...




I keep hearing about his XPW, any reason why it runs so good?


----------



## Hedgerow (Jan 8, 2012)

parrisw said:


> Cool, thanks!



It's a fine 372... By anyone's standards...


----------



## Andyshine77 (Jan 9, 2012)

Mastermind said:


> At the risk of turning this thread into an oil thread I'll throw this out there. If a crappy ethanol laced fuel is being used the use of a good oil is even more important. In the oils I use the ability to mix with alcohol is of the utmost importance.
> 
> And yeah, 200psi on crappy fuel is way too much. *IMHO*



All depends on how much ethanol we are talking about. Some oils like R50 mix fine up to about 20% ethanol, and even then is rare and only a separation issue during storage. Personally I haven't seen any mixing issues of any kind. Keep the fuel fresh, run good mix and enough of it and you'll be fine. Now if they start adding more ethanol things may change, but even then it's an easy fix for the oil producers.


----------



## jropo (Jan 10, 2012)

rms61moparman said:


> HaHaHa!!!!
> 
> 
> Try this.............if it works!
> ...





Mastermind said:


> [video=youtube;dFlXTRLohq4]http://www.youtube.com/watch?v=dFlXTRLohq4&feature=g-upl&context=G26ecfc1AUAAAAMgAWAA[/video]






Was there build threads for these saws? If so I can't find them, please help w/ link.


----------



## rms61moparman (Jan 10, 2012)

Try "Wildthing races at GTGs".
I don't know if there are individual build threads on each one or not.


Mike


----------



## jropo (Jan 10, 2012)

Thank you


----------



## jimdad07 (Jan 10, 2012)

Not trying to hijack, but if you guys can please check this thread out: http://www.arboristsite.com/off-topic-forum/188558-23.htm#post3392218, this family could use some well wishing.


----------



## RiverRat2 (Jan 10, 2012)

jimdad07 said:


> Not trying to hijack, but if you guys can please check this thread out: http://www.arboristsite.com/off-topic-forum/188558-23.htm#post3392218, this family could use some well wishing.



Already on it,,,, Thanks for the heads up for those who may not be aware,,,

Brian and Jani are some super fine people,,, Keep them in yer thoughts and prayers for sure!!!!


----------



## RiverRat2 (Jan 10, 2012)

Hedgerow said:


> I wondered about that... That saw is just nasty... It may be be pushing the envelope... How many hours you got on it as of this week...??? *And of course, if you get tired of it you know where it can come live...
> Just sayin.*..



Yeah right,,,, Dream on,,,, that saw wont be leavin TN,,,,, unless Durand is totin it!!!!


----------



## jimdad07 (Jan 10, 2012)

That Wildthang is sick. I think I would own one. I might have to try building one some day, I could cut my firewood real fast with that.


----------



## Hedgerow (Jan 11, 2012)

RiverRat2 said:


> Yeah right,,,, Dream on,,,, that saw wont be leavin TN,,,,, unless Durand is totin it!!!!



It left TN once!!! Next time, it may stay in MO!!! I'll trade him for a Mac...
:msp_biggrin:


----------



## komatsuvarna (Jan 11, 2012)

Hedgerow said:


> *It left TN once*!!! Next time, it may stay in MO!!! I'll trade him for a Mac...
> :msp_biggrin:



In my hands!!

Ill have to think about the Mac trade for a bit lol.


----------



## Freakingstang (Oct 20, 2012)

So what about Popup AND windows in something that had a slab sided piston to begin with?


----------



## parrisw (Oct 20, 2012)

Freakingstang said:


> So what about Popup AND windows in something that had a slab sided piston to begin with?



Works in a 372.


----------



## Mastermind (Oct 20, 2012)

Freakingstang said:


> So what about Popup AND windows in something that had a slab sided piston to begin with?





parrisw said:


> Works in a 372.



I works in any engine as a good way to run a lighter piston. Does it help build torque or rpm???? Both???? Discuss.....


----------



## Jacob J. (Oct 20, 2012)

Mastermind said:


> I works in any engine as a good way to run a lighter piston. Does it help build torque or rpm???? Both???? Discuss.....



Don't you have GTG saws you should be working on??


----------



## Mastermind (Oct 20, 2012)

Jacob J. said:


> Don't you have GTG saws you should be working on??



Shaking da bush Boss......... :cool2:


----------



## Jacob J. (Oct 20, 2012)

Mastermind said:


> Shaking da bush Boss......... :cool2:



Back to the salt mines....


----------



## Jacob J. (Oct 20, 2012)

One of the things I look at when modifying the piston is how heavy the flywheel is on the saw. 

Stihls *typically* have heavier flywheels than Husqvarnas...


----------



## Mastermind (Oct 20, 2012)

Jacob J. said:


> Don't you have GTG saws you should be working on??



Three XPWs and a 461......


----------



## Jacob J. (Oct 20, 2012)

Mastermind said:


> Three XPWs and a 461......



Man, that 461 jug sure looks funky.


----------



## Mastermind (Oct 20, 2012)

Jacob J. said:


> Man, that 461 jug sure looks funky.



It's just different......but in a good way. 

Think of the way a 361 runs compared to a 036......that's how I would compare the 461 to the 046/460.


----------



## Jacob J. (Oct 20, 2012)

Mastermind said:


> It's just different......but in a good way.
> 
> Think of the way a 361 runs compared to a 036......that's how I would compare the 461 to the 046/460.



It'll be interesting to see what kind of times you end up with in the wood.


----------



## rms61moparman (Oct 20, 2012)

parrisw said:


> Works in a 372.





But it isn't the only thing that works in a 372!


Mike


----------



## Mastermind (Oct 20, 2012)

rms61moparman said:


> But it isn't the only thing that works in a 372!
> 
> 
> Mike



No it's not. I never run a windowed piston in a 372.


----------



## Mastermind (Oct 20, 2012)

Mastermind said:


> No it's not. I never run a windowed piston in a 372.



I have been looking at the 268 piston pretty hard of late though.....


----------



## jropo (Oct 20, 2012)

Freakingstang said:


> So what about Popup AND windows in something that had a *slab sided piston* to begin with?



Is that the type of piston with the flat sides by the wrist pin?


----------



## Tree Sling'r (Oct 20, 2012)

Mastermind said:


> It's just different......but in a good way.
> 
> Think of the way a 361 runs compared to a 036......that's how I would compare the 461 to the 046/460.



I agree Randy, I like them.


----------



## Freakingstang (Oct 20, 2012)

parrisw said:


> Works in a 372.



This has been my experience in a stock bore 372 (not a 375).




Mastermind said:


> I works in any engine as a good way to run a lighter piston. Does it help build torque or rpm???? Both???? Discuss.....




I've been out of the loop/world for 4-5 years. The last saw i played with was a 372 with a machine piston with a .040 dome. It was either a 268xp or 266 windowed piston. I can't remember to be honest. It worked well, but I honestly hadn't played and tested it to the extent I wanted to. Meaning, i haven't gone back in and played with opening up the lowers more, changing timing, etc. It definately revs quicker than my 371 with a windowed piston with no dome, but I don't have any side by side comparisons. For a work saw with a 24" bar, it runs good. I've never seen the 372 as a torquey saw compared to a 460 or 7900 if that makes sense? I acutally read this whole thread the other night looking for Piston info. I picked up a dolmar 5100s with a melted piston and was looking for alternative pistons to install in it And got to thinking, since the 5100 and 7900 originally had a windowed piston but the newer replacements are slab sided... 

Eric made a comment about a high compression 372/275 running too hot and detonation earlier in the thread. i am wondering if this is where a windowed piston would help with the cooling charge on the bottom side of the piston? I'm just thinking out loud. There was a ton of great info and ideas in this thread.


----------



## Freakingstang (Oct 20, 2012)

jropo said:


> Is that the type of piston with the flat sides by the wrist pin?



Yes. Here is a stock 371/372 single single ring oem piston, a 268 and a 266. I just can't remember which of the 266/268 pistons is which. but both are too "tall" to use stock without cutting them down or cutting the squish band. The skirt is also about 1mm shorter, so if you have already lowered intake and transfers....



Mastermind said:


> I have been looking at the 268 piston pretty hard of late though.....






















Notice one is a full skirt, one is a "stihl" type piston. Once you machine them, you don't have to cut the jug. I did not have access to a mill or lathe when I was playing with saws 4-5 years ago, so I had to really do some research and make my choices well. It was easiest for me to machine a piston than it was to cut a cylinder in a lathe... I have not ran the full skirt windowed piston yet, but there is significant weight differences between the three by feel. I don't have a scale to wiegh them though.


----------



## blsnelling (Oct 20, 2012)

Andre and I have run our 71cc 372s back to back many times now. They are so close it's not funny. If one has an edge, it's Andre's. Mine has a windowed piston, his does not. The moral of the story is that a windowed piston is not required. Does it hurt? Not necessarily. But then again, every saw is different and your mileage may vary.


----------



## Freakingstang (Oct 20, 2012)

blsnelling said:


> Andre and I have run our 71cc 372s back to back many times now. They are so close it's not funny. If one has an edge, it's Andre's. Mine has a windowed piston, his does not. The moral of the story is that a windowed piston is not required. Does it hurt? Not necessarily. But then again, every saw is different and your mileage may vary.



Short bar in small wood or big bar in big wood?

Did you do less lower transfer work to the windowed piston for the case volume/velocity issues?


----------



## blsnelling (Oct 20, 2012)

Freakingstang said:


> Short bar in small wood or big bar in big wood?
> 
> Did you do less lower transfer work to the windowed piston for the case volume/velocity issues?



I only case match the lowers. I do not hog them out. Comparisons were made last weekend in both 10" cants and 20" Oak.


----------



## Trx250r180 (Oct 20, 2012)

Mastermind said:


> Three XPWs and a 461......



your gettin pretty good with that claw hammer and punch :msp_wink:


----------



## rms61moparman (Oct 20, 2012)

blsnelling said:


> *Andre and I have run our 71cc 372s back to back many times now*. They are so close it's not funny. If one has an edge, it's Andre's. Mine has a windowed piston, his does not. The moral of the story is that a windowed piston is not required. Does it hurt? Not necessarily. But then again, every saw is different and your mileage may vary.







Yours and who's?????????


Mike


----------



## PLAYINWOOD (Oct 20, 2012)

blsnelling said:


> I only case match the lowers. I do not hog them out. Comparisons were made last weekend in both 10" cants and 20" Oak.



Any compression number difference?


----------



## buck futter (Nov 13, 2012)

*great thread!*

great Thread guys!

JJ I'm glad you remembered when I adjusted the squish on the 460 with emery cloth. I only needed 2 thou though.

so what ended up being the new hot set up for the 372's who won Terry? What did he do to make the difference?

Regards

David


----------



## Andyshine77 (Nov 14, 2012)

buck futter said:


> great Thread guys!
> 
> JJ I'm glad you remembered when I adjusted the squish on the 460 with emery cloth. I only needed 2 thou though.
> 
> ...



From what I've been told and seen, Randy and Tree monkey are making pretty strong 372's. However Mike's 372 that has a pop up is still competitive. I honestly think cutting the squish band makes a bigger difference than I or anyone originally thought. I've talked to a few very good builders that concur. IMHO pop ups give you more compression, but not always noticeable gains, and in some cases it may be detrimental. On top of that replacing the piston is now an issue, and I would never recommend a pop up in a true work saw.

Everything I said is however subject to change lol.


----------



## parrisw (Nov 14, 2012)

My tried and true 372 with popup and windows still impresses all that run it. I haven't shaken down the new one enough to know yet if its any better or not.


----------



## Mastermind (Nov 14, 2012)

Andyshine77 said:


> From what I've been told and seen, Randy and Tree monkey are making pretty strong 372's. However Mike's 372 that has a pop up is still competitive. I honestly think cutting the squish band makes a bigger difference than I or anyone originally thought. I've talked to a few very good builders that concur. IMHO pop ups give you more compression, but not always noticeable gains, and in some cases it may be detrimental. On top of that replacing the piston is now an issue, and I would never recommend a pop up in a true work saw.
> 
> Everything I said is however subject to change lol.





parrisw said:


> My tried and true 372 with popup and windows still impresses all that run it. I haven't shaken down the new one enough to know yet if its any better or not.



The best running 372 I've built yet had the squish band cut just enough to flatten it and a .025 popup. I'm not done with popups completely. The 550 and 562XP are two saws that work well with popups too. Sometimes the transfer height is so far off after cutting the squish that it makes more sense to do the popup.

But everything we are doing today will be obsolete in a couple of years.


----------



## Hedgerow (Nov 14, 2012)

Not a fan of pop up's... I put them in the category of "What to use when you absolutely, positively, have no other option's and need more compression..."
Sometimes I think a good running saw with a pop up runs well "In spite" of having one...
:msp_rolleyes:

Flame suit is on now...
:after_boom:


----------



## Mastermind (Nov 14, 2012)

Hedgerow said:


> Not a fan of pop up's... I put them in the category of "What to use when you absolutely, positively, have no other option's and need more compression..."
> Sometimes I think a good running saw with a pop up runs well "In spite" of having one...
> :msp_rolleyes:
> *
> ...



You don't need one in my mind. The cut squish is great when you want to lower the exhaust and/or transfers. I can make a #### load of compression that way too.....I like compression ya know. 

Popups were all the rage a couple of years ago......remember?


----------



## Hedgerow (Nov 14, 2012)

Mastermind said:


> You don't need one in my mind. The cut squish is great when you want to lower the exhaust and/or transfers. I can make a #### load of compression that way too.....I like compression ya know.
> 
> Popups were all the rage a couple of years ago......remember?



Yup... And I've used em'... And I've replaced em'... The 372 was an eye opener...
Replace pop up with flat top...
Lose 15lbs of comp...
Gain 7% useable RPM's in the cut...
Still without a machined squish band... 
Go figure...


----------



## Trx250r180 (Nov 14, 2012)

this saw has no pop up ,totally stock piston View attachment 262262


----------



## cowroy (Nov 14, 2012)

Hedgerow said:


> Yup... And I've used em'... And I've replaced em'... The 372 was an eye opener...
> Replace pop up with flat top...
> Lose 15lbs of comp...
> Gain 7% useable RPM's in the cut...
> ...



When you say useable rpm's do you mean torque?


----------



## blsnelling (Nov 14, 2012)

My 372 certainly doesn't lack RPMs and has a popup. Never the less, I'm going to try the next one without it. I think there's more to it than just with or without a popup.


----------



## Hedgerow (Nov 14, 2012)

cowroy said:


> When you say useable rpm's do you mean torque?



I mean it raised it's peak horsepower in the cut... Tuned at 14,700 as opposed to 13,900 no load and holds ~1000 more RPM's in the cut... In other words. "Raised it's happy range of rpm's without losing it's torque"...
And I swear it runs cooler now, but can't quantify that...


----------



## ChipMonger (Nov 14, 2012)

trx250r180 said:


> this saw has no pop up ,totally stock piston View attachment 262262



Trx,

Thats a helluva lot of compression Randy was able to get, impressive. Couple questions:

1. What do you use the saw for...Dont just say cuttin' wood either lol:msp_sneaky:

2. Do you think high compression like that puts excessive force on the crank and crank bearings? or is it still to early to tell. Just curious, not trying to start a battle with anyone if this has already been discussed.


----------



## Naked Arborist (Nov 14, 2012)

Popups were all the rage in the 60-70's. We see where that went with engine manufacturers. I do believe that a dished piston would have even more TQ in the cut and might squeak out a few more rpm. The problem is getting enough compression from such a small swept volume. It is a know fact that round boom areas make more grunt given enough stuffing and squish squash turbulence. Now who knows why? I do...

I like my windows polished clean and not hogged out. They reduce crown temps although not always needed. If they have no "through" flow they do basically nothing.


----------



## Trx250r180 (Nov 14, 2012)

ChipMonger said:


> Trx,
> 
> Thats a helluva lot of compression Randy was able to get, impressive. Couple questions:
> 
> ...



i just use it around the house cleaning up and firewood ,clearing land also ,it sure runs good ,it has lots of tourque ,in my opinion it runs smooth for power ,i dont over rev so dont think bearings be too much a factor ,pullstart parts maybe ,this sucker will rip the pullstart out of your hand if you dont know how to start it

i think for a saw getting used daily he keeps compresion down in the 200 range

this 440 also has a 460 jug on it ,im not sure if that made compresion any higher or not


----------



## Mastermind (Nov 14, 2012)

Naked Arborist said:


> Popups were all the rage in the 60-70's. We see where that went with engine manufacturers. I do believe that a dished piston would have even more TQ in the cut and might squeak out a few more rpm. The problem is getting enough compression from such a small swept volume. It is a know fact that round boom areas make more grunt given enough stuffing and squish squash turbulence. Now who knows why? I do...
> 
> I like my windows polished clean and not hogged out. They reduce crown temps although not always needed. If they have no "through" flow they do basically nothing.



I know why too....but let's wait and see what the masses say......



trx250r180 said:


> i just use it around the house cleaning up and firewood ,clearing land also ,it sure runs good ,it has lots of tourque ,in my opinion it runs smooth for power ,i dont over rev so dont think bearings be too much a factor ,pullstart parts maybe ,this sucker will rip the pullstart out of your hand if you dont know how to start it
> 
> i think for a saw getting used daily he keeps compresion down in the 200 range
> 
> this 440 also has a 460 jug on it ,im not sure if that made compresion any higher or not



I'm not sure why the saw ended up so high......you sure that gauge is right?


----------



## Trx250r180 (Nov 14, 2012)

Mastermind said:


> I know why too....but let's wait and see what the masses say......
> 
> 
> 
> I'm not sure why the saw ended up so high......you sure that gauge is right?



my stock 036 was reading 145 on the same guage then 175 on same guage when i yanked the base gasket out this saw i checked a couple times, strong 225 each time ,ill try the 461 see what it reads on this guage ,i think you were an even 200 ? did you ever recheck the 461 after had some time on it ?


----------



## Mastermind (Nov 14, 2012)

trx250r180 said:


> my stock 036 was reading 145 on the same guage then 175 on same guage when i yanked the base gasket out this saw i checked a couple times, strong 225 each time ,ill try the 461 see what it reads on this guage ,i think you were an even 200 ? did you ever recheck the 461 after had some time on it ?



I didn't recheck the 461.......what is your elevation?


----------



## Trx250r180 (Nov 14, 2012)

Mastermind said:


> I didn't recheck the 461.......what is your elevation?



i live on the ocean ,maybe 300 feet elevation at the house

i had the 461 in the truck so put a guage on it at work here ,1 line under the 200 psi line cold ,the 461 doesnt yank the handle from my hand like the hybrid does


----------



## rburg (Nov 14, 2012)

That 461 sure is a good runner. One of the best I ran at the gtg.


----------



## HEAVY FUEL (Nov 14, 2012)

parrisw said:


> My tried and true 372 with popup and windows still impresses all that run it. I haven't shaken down the new one enough to know yet if its any better or not.





Mastermind said:


> The best running 372 I've built yet had the squish band cut just enough to flatten it and a .025 popup. I'm not done with popups completely. The 550 and 562XP are two saws that work well with popups too. Sometimes the transfer height is so far off after cutting the squish that it makes more sense to do the popup.
> 
> But everything we are doing today will be obsolete in a couple of years.





Hedgerow said:


> Yup... And I've used em'... And I've replaced em'... The 372 was an eye opener...
> Replace pop up with flat top...
> Lose 15lbs of comp...
> Gain 7% useable RPM's in the cut...
> ...



WTH is all this 372 talk??? GO RED!!! :hmm3grin2orange:

[video=youtube_share;n6zdFQfO7yE]http://youtu.be/n6zdFQfO7yE[/video]


----------



## Hedgerow (Nov 14, 2012)

HEAVY FUEL said:


> WTH is all this 372 talk??? GO RED!!! :hmm3grin2orange:
> 
> [video=youtube_share;n6zdFQfO7yE]http://youtu.be/n6zdFQfO7yE[/video]



Naaaa... 

BLACK!!!!


----------



## Mastermind (Nov 14, 2012)

Hedgerow said:


> Naaaa...
> 
> BLACK!!!!



Go creamsickle!!!!!!!


----------



## Hedgerow (Nov 14, 2012)

Eeewww!!!!!
Bad monkey!!!!


----------



## tree monkey (Nov 14, 2012)

:msp_confused::msp_confused:


----------



## HEAVY FUEL (Nov 14, 2012)

Hedgerow said:


> Eeewww!!!!!
> Bad monkey!!!!



He delivers ice cream and ports saws!!! A dream come true...


----------



## Mastermind (Nov 14, 2012)

Hedgerow said:


> Eeewww!!!!!
> Bad monkey!!!!



I throw poop too.


----------



## parrisw (Nov 14, 2012)

Mastermind said:


> I throw poop too.



Is this you Randy by chance? 

[video=youtube;6DBuk91phkI]http://www.youtube.com/watch?v=6DBuk91phkI[/video]


----------



## parrisw (Nov 14, 2012)

Or maybe this is you?

[video=youtube;DmskJe0UuG0]http://www.youtube.com/watch?v=DmskJe0UuG0[/video]


----------



## Mastermind (Nov 14, 2012)

parrisw said:


> Is this you Randy by chance?
> 
> [video=youtube;6DBuk91phkI]http://www.youtube.com/watch?v=6DBuk91phkI[/video]



Nope.......that's Scott.


----------



## Mastermind (Nov 14, 2012)

parrisw said:


> Or maybe this is you?
> 
> [video=youtube;DmskJe0UuG0]http://www.youtube.com/watch?v=DmskJe0UuG0[/video]



That's andydodgegeek....


----------



## parrisw (Nov 14, 2012)

Mastermind said:


> That's andydodgegeek....



I'll keep looking.


----------



## parrisw (Nov 14, 2012)

[video=youtube;EGvD5OSkJ_Q]http://www.youtube.com/watch?v=EGvD5OSkJ_Q[/video]


----------



## Hedgerow (Nov 14, 2012)

Holy cow... I go out to the shop for a couple hours, and it turns into a zoo around here.!!!! You'd think the aussie's got in here!!!
:msp_sneaky:


----------



## AUSSIE1 (Nov 15, 2012)

Hedgerow said:


> Holy cow... I go out to the shop for a couple hours, and it turns into a zoo around here.!!!! You'd think the aussie's got in here!!!
> :msp_sneaky:



Tutored by the best!


----------



## HEAVY FUEL (Nov 15, 2012)

Hedgerow said:


> Holy cow... I go out to the shop for a couple hours, and it turns into a zoo around here.!!!! You'd think the aussie's got in here!!!
> :msp_sneaky:



Looks like we've gone from the arborist site to the ape site.


----------



## Hedgerow (Nov 15, 2012)

HEAVY FUEL said:


> Looks like we've gone from the arborist site to the ape site.



It's gonna take hours to clean up all the monkey poo in here...
:bad_smelly:


----------



## mcb (Dec 24, 2012)

041AV im working on, closed piston with side fed lower transfers. im tempted to cut some windows. thoughts?


----------



## Mastermind (Dec 24, 2012)

mcb said:


> 041AV im working on, closed piston with side fed lower transfers. im tempted to cut some windows. thoughts?



You *might* find a slight gain that could be realized with a stop watch.....but there would be a cooling effect on the piston crown......which might be a good thing. The trouble is that adding windows to a non-windowed piston can cause the piston to crack after some run time. I've built a few 041s and gotten great gains without modding the piston.


----------



## mcb (Dec 24, 2012)

well, im just about to get into the port timing and setting the squish on a lathe with jug mandrel. any suggestions? id like to move the peak torque up a thousand rpm or so. seems to me like its really lacking on blowdown and intake duration is pretty short. 

ive cleaned up the transition from block to jug and might be laying some epoxy in there to up the crankcase compression ratio. whats your take on that route?


----------



## mcb (Dec 24, 2012)

btw, i just drove through jamestown 2 weeks ago, nice quiet place. we bought a house on the edge of mayland and crossville last week. they got any meet and greets out that way?


----------



## Mastermind (Dec 24, 2012)

mcb said:


> well, im just about to get into the port timing and setting the squish on a lathe with jug mandrel. any suggestions? id like to move the peak torque up a thousand rpm or so. seems to me like its really lacking on blowdown and intake duration is pretty short.
> 
> ive cleaned up the transition from block to jug and might be laying some epoxy in there to up the crankcase compression ratio. whats your take on that route?



I just build work saws and never add anything to the case. Everything I do has to hold up in a work environment.......so epoxy is never used. I ain't getting into race saws......ever.

Look at the crank counterweights......they get right in the way of all the case/jug matching you're looking for. 

Here's the thread I did on an 041 Super.....

http://www.arboristsite.com/chainsaw/200469.htm


----------



## Mastermind (Dec 24, 2012)

mcb said:


> btw, i just drove through jamestown 2 weeks ago, nice quiet place. we bought a house on the edge of mayland and crossville last week. they got any meet and greets out that way?



Terry Landrum puts on a GTG every year. It's near Olivier Springs.....


----------



## mcb (Dec 24, 2012)

ive done devcon inside manifolds, oil pumps and oil galleys since 2003 with no failures. ill post pics later, this block had a 1/4" ledge at the jug.


----------



## Mastermind (Dec 24, 2012)

mcb said:


> ive done devcon inside manifolds, oil pumps and oil galleys since 2003 with no failures. ill post pics later, this block had a 1/4" ledge at the jug.



Devcon is good stuff.........


----------



## Naked Arborist (Dec 28, 2012)

Mastermind said:


> You *might* find a slight gain that could be realized with a stop watch.....but there would be a cooling effect on the piston crown......which might be a good thing. The trouble is that adding windows to a non-windowed piston can cause the piston to crack after some run time. I've built a few 041s and gotten great gains without modding the piston.



I think the cracking is caused by way too much "introduced" cooling going through a thin pin wall. Most windowed pistons I have seen are much thicker in the narrow pin wall area just like forged drag slugs.


----------



## wigglesworth (Jan 15, 2015)

Good stuff here...


----------



## Mastermind (Jan 15, 2015)

Popups are for pansies.


----------



## SAWMIKAZE (Jan 15, 2015)

Im a pansy  i have 3 slow saws with pop-ups .


----------



## Mastermind (Jan 15, 2015)

When I was just getting started, I built a lot of saws with popups. 

Will they work? Yep. 

Are they the best approach? No. 

Are they easier? Yes

Less chance of fubarring a jug? Yes


----------



## Mastermind (Jan 15, 2015)

The pansy part ain't directed at the saw owner......it's directed at the guy that is not willing to take the extra time, and a bit of risk to do a better job for the customer.


----------



## Mastermind (Jan 15, 2015)

OK? Bye now.


----------



## srcarr52 (Jan 15, 2015)

Mastermind said:


> The pansy part ain't directed at the saw owner......it's directed at the guy that is not willing to take the extra time, and a bit of risk to do a better job for the customer.



I cut the chamber, not because it's easy but because it's the right thing to do.


----------



## Mastermind (Jan 15, 2015)

I agree Shawn.

I also like the added control I have over the port timing. 

For instance, on a lot of saws, I can lower the exhaust. I can make some of the older saws (think 262XP and friends) run like they would never run with a popup because of that.


----------



## Hedgerow (Jan 15, 2015)

How do you deal with too much intake due to dropping the jug?..


----------



## Mastermind (Jan 15, 2015)




----------



## Mastermind (Jan 15, 2015)

Next?


----------



## Hedgerow (Jan 15, 2015)

Mastermind said:


> View attachment 394908


There's 2 bubbles in it...

Re-do....


----------



## Trx250r180 (Jan 15, 2015)

Is that Toms jug ?


----------



## Mastermind (Jan 15, 2015)

That is a "Myth Buster" jug.


----------



## Mastermind (Jan 15, 2015)

nmurph said:


> Spoken like a true former pansy.



Oh snap. 

You are right though. 

Are we the judged by who we were, are who we've become though?


----------



## a. palmer jr. (Jan 15, 2015)

Jacob J. said:


> I like having windows in my pickup, so I can see where I'm going.


 I have a lot of pop ups with windows, thinking of going to a Mac.


----------



## nmurph (Jan 15, 2015)

Mastermind said:


> Popups are for pansies.



Spoken like a true former pansy.


----------



## Mastermind (Jan 15, 2015)

You're fired Neal. 

Pack your stuff.


----------



## Chris-PA (Jan 15, 2015)

Every Zenoah engine I have seen had a domed piston, but then again those guys are pikers and don't know anything about 2-stoke engines. I can't tell if the new 543 piston is domed though:







(From http://www.arboristsite.com/community/threads/inside-the-husqvarna-543xp.260309/#post-4886305 )

This is important as it is now a moral issue, and if 543's have domed pistons they will all need to be destroyed. Certainly all those GZ4000/4500 saws are all wrong and cannot possibly work, and their designers are evil. 

I am amazed at the histrionics over a minor technical detail that maybe a dozen people on the planet have any interest in.


----------



## Metals406 (Jan 15, 2015)

Is this the thread where we post pictures of cheese?


----------



## Mastermind (Jan 15, 2015)

You are confused Chris. 

A popup is not a dome. 

This is a popup......note the obstruction on the crown? 




Yes the 543XP has a domed piston, I just ported one. I still cut the squish band. It was far more complicated than a flat squish band......


----------



## Mastermind (Jan 15, 2015)

The most important thing here is the ability to lower the exhaust port.......that is not possible when using a popup.


----------



## Hedgerow (Jan 15, 2015)

Mastermind said:


> The most important thing here is the ability to lower the exhaust port.......that is not possible when using a popup.


And component replacement in the future, if needed.


----------



## Trx250r180 (Jan 15, 2015)

Metals406 said:


> Is this the thread where we post pictures of cheese?


Am going through cheese withdrawls ,the store is out of tillamook and string right now


----------



## Metals406 (Jan 15, 2015)

Trx250r180 said:


> Am going through cheese withdrawls ,the store is out of tillamook and string right now


I wouldn't take that laying down! Time for a strongly worded letter to the store manager!!


----------



## Chris-PA (Jan 15, 2015)

Mastermind said:


> You are confused Chris.
> 
> A popup is not a dome.
> 
> ...


Yes I understand that - then again if you go back to the first page of this thread it was really about both domed pistons and popups. The two are minor variations of the same thing, differing only in how steep the edge of the lump is. Other recent discussion has been about how transfer flow patterns are disturbed by the presence of a disruption on the piston face, and also included domed pistons. I included the comment about Zenoah engines to point out that this is not really a settled topic, and that some rather capable engine designers are still not using flat pistons. 

But I don't think that's _really_ what this thread revival is about anyway.


----------



## Mastermind (Jan 15, 2015)

You're probably right......

I think Scott brought it back up because he's feeling pretty damn good and wants to have spirited discussion.


----------



## Mastermind (Jan 15, 2015)

So.....aside from the whole popup thing.....

What about windowed pistons, and their effect on case compression? 

And these days all the cool kids are discussing intake height. How does that enter into this conversation?


----------



## srcarr52 (Jan 15, 2015)

Mastermind said:


> I agree Shawn.
> 
> I also like the added control I have over the port timing.
> 
> For instance, on a lot of saws, I can lower the exhaust. I can make some of the older saws (think 262XP and friends) run like they would never run with a popup because of that.



Stihl 660 is a classic. 



Mastermind said:


> You are confused Chris.
> 
> A popup is not a dome.
> 
> ...



I usually deal with domed pistons by chucking the piston in the lathe to dial in the cross to the start angle of the face and then add 1- 2 degree and cut the squish at that angle.


----------



## Hedgerow (Jan 15, 2015)

I like case compression... But when to say when??? How much is too much?


----------



## srcarr52 (Jan 15, 2015)

Mastermind said:


> So.....aside from the whole popup thing.....
> 
> What about windowed pistons, and their effect on case compression?
> 
> And these days all the cool kids are discussing intake height. How does that enter into this conversation?



Your intake opening has an effect on your effective crankcase compression. Hence why someone would fill in the bottom of an intake port.


----------



## Mastermind (Jan 15, 2015)

Depends on the application Matt.

In a high RPM saw.......I would want much less than in a working saw.


----------



## srcarr52 (Jan 15, 2015)

Hedgerow said:


> I like case compression... But when to say when??? How much is too much?



Matters what altitude you're at. Chew on that.


----------



## Mastermind (Jan 15, 2015)

How about attitude?

I'm a smart ass most of the time.


----------



## Mastermind (Jan 15, 2015)

Chris is right about one thing......

I have been trying to use Peer Pressure to get Brad to take the plunge and cut some squish bands. 

I admit that.


----------



## Hedgerow (Jan 15, 2015)

Mastermind said:


> Depends on the application Matt.
> 
> In a high RPM saw.......I would want much less than in a working saw.


Agreed... But would you say anything over 158-160 intake duration is excessive and will turn your saw into a fuel swilling, slow excellerating, pig? Or would it have more to do with the relationship between case volume/transfer length/ and overall crossectional area of your upper transfers??


----------



## Hedgerow (Jan 15, 2015)

srcarr52 said:


> Matters what altitude you're at. Chew on that.


You should have bought an arctic cat...
I told you those polaris' were bad juju..


----------



## Hedgerow (Jan 15, 2015)

srcarr52 said:


> Your intake opening has an effect on your effective crankcase compression. Hence why someone would fill in the bottom of an intake port.


I know a couple guys been doing that for years...


----------



## Mastermind (Jan 15, 2015)

Hedgerow said:


> Agreed... But would you say anything over 158-160 intake duration is excessive and will turn your saw into a fuel swilling, slow excellerating, pig? Or would it have more to do with the relationship between case volume/transfer length/ and overall crossectional area of your upper transfers??



I don't think there are any "always" situations.

The MS660 doesn't seem to mind intake durations in the 170* range at all. 

Some other saws don't work well at all in those ranges. So........I don't really know. 

I've still got so much to learn too. I feel like I'm just now getting a decent scratch in the surface.....


----------



## Hedgerow (Jan 15, 2015)

Mastermind said:


> I don't think there are any "always" situations.
> 
> The MS660 doesn't seem to mind intake durations in the 170* range at all.
> 
> ...


I haven't even cut the plastic off yet...
But....
Knowing what you know, "why" can the 660 handle that kind of intake duration?
What's different about it than say, a 390? 
There should be a huge difference in case volume, right?


----------



## srcarr52 (Jan 15, 2015)

Hedgerow said:


> You should have bought an arctic cat...
> I told you those polaris' were bad juju..



It drives right past all those arctic kitties, when I can keep it together. All except for the first failure have been self inflicted.


----------



## Mastermind (Jan 15, 2015)

The 390 has much tighter, higher velocity transfer ports. It also has a full skirt piston........


----------



## Mastermind (Jan 15, 2015)

The MS660 has very open.......lazily moving transfers.......and a windowed piston

Apples VS grapes.


----------



## srcarr52 (Jan 15, 2015)

Mastermind said:


> I don't think there are any "always" situations.
> 
> The MS660 doesn't seem to mind intake durations in the 170* range at all.
> 
> ...



The 660 is an odd duck, what somehow works in it won't in about any other saw. 

If you put 170 deg ex duration in a Husky, as seen in some stock 660's, you better have a pipe on it.


----------



## Hedgerow (Jan 15, 2015)

Mastermind said:


> The MS660 has very open.......lazily moving transfers.......and a windowed piston
> 
> Apples VS grapes.


Exactly.. You use a completely different approach to get where you want...
Now all ya gotta do is figure out why, and let me know...
Cause I ain't got time fo dat ****...


----------



## Mastermind (Jan 15, 2015)

I normally port ten saws a week.......I ain't got time fo dat **** either.


----------



## Hedgerow (Jan 15, 2015)

Mastermind said:


> I normally port ten saws a week.......I ain't got time fo dat **** either.


Shaun's fixing his blowed up Polaris now, so he ain't got time either...
Maybe Chris has time to figure it out.
Wiggs would take too damn long...


----------



## Mastermind (Jan 15, 2015)

I like Arctic Cat better......


----------



## srcarr52 (Jan 15, 2015)

Mastermind said:


> I like Arctic Cat better......


Reported!


----------



## komatsuvarna (Jan 15, 2015)

Whats an Artic Cat?

Must be kin to a Dolmar....


----------



## mdavlee (Jan 15, 2015)

komatsuvarna said:


> Whats an Artic Cat?
> 
> Must be kin to a Dolmar....


The best sled to ever hit snow


----------



## komatsuvarna (Jan 15, 2015)

mdavlee said:


> The best saw to ever throw in the ditch



I agree!















haha, bet Hedge will like that!


----------



## srcarr52 (Jan 15, 2015)

komatsuvarna said:


> Whats an Artic Cat?
> 
> Must be kin to a Dolmar....



A ditch pickle.


----------



## Chris-PA (Jan 15, 2015)

Hedgerow said:


> Shaun's fixing his blowed up Polaris now, so he ain't got time either...
> Maybe Chris has time to figure it out.
> Wiggs would take too damn long...


Lol - I kinda doubt I'm ever gonna figure out anything about 660s and 390s porting Poulans and Earthquakes!

On the other hand I just got in from the barn after putting the jug back on the Earthquake for my forth try at porting it. I made several of the mistakes listed here and it's been a lazy dog for that. I took too much material from the lower transfers (not terribly but still counterproductive). I had some 46deg of case compression which I think was too much even given the lost case volume. And my port edges were too rounded. 

I didn't want to raise the exhaust, so now the intake is at 168 duration and the case compression is at 43. I'll see on the weekend what that did.


----------



## Metals406 (Jan 15, 2015)

I did a 066 @ 176 & 174.

It's a tree raper.

Numbers based on pistons, transfers, combustion chambers, case volume, etc. . . Makes saw porting tricky business.

I'm sure there's a relationship there that could be expressed in a cookie-cutter ratio or formula. . . But I ain't smart enough to figure it all out.

There's a Solo out there right now, that seems like it runs on NOS and superman blood. Dang thing is stupid fast, & doesn't even have a cut head.

I'd like to peer into that saw builders head.


----------



## Mastermind (Jan 15, 2015)

Chris-PA said:


> Lol - I kinda doubt I'm ever gonna figure out anything about 660s and 390s porting Poulans and Earthquakes!



Don't sell yourself short Chris........you have some damn good ideas.


----------



## Hedgerow (Jan 15, 2015)

srcarr52 said:


> A ditch pickle.



Hey... You hear that noise outside?
It's them dern arctic cats drivin around in yer snow...


mdavlee said:


> The best sled to ever hit snow



BAM!!!
In arctic cat green...


----------



## KenJax Tree (Jan 15, 2015)

Matt speaking of snowmobiles Tip up town starts this weekend so we're all loaded up ready to go


----------



## spencerpaving (Jan 15, 2015)

Up here the cats donate their entry fees to the Polaris guys....just sayin


----------



## KenJax Tree (Jan 15, 2015)

I have an 01 Yamaha SRX 700


----------



## srcarr52 (Jan 15, 2015)

Well I found a decently clogged fuel filter. Probably was fine until someone mentioned lunch and I realized how hungry I was. Then the average speed jumped up to about 90 mph.


----------



## Hedgerow (Jan 15, 2015)

spencerpaving said:


> Up here the cats donate their entry fees to the Polaris guys....just sayin


Cause they be riding around while the Polaris guys are fixing their sleds at the top of the hill...

Vroom....
Boom....

Hahahahahaha!!!!!!!


----------



## spencerpaving (Jan 16, 2015)

Hedgerow said:


> Cause they be riding around while the Polaris guys are fixing their sleds at the top of the hill...
> 
> Vroom....
> Boom....
> ...


so you've seen my race sled then... I had a year where I was sprayin a little too lot and blew head O-rings on every run


----------



## tree monkey (Jan 16, 2015)

I just spent 2 hr's typing the longest post of my life, on a broken keyboard, with one finger, only to have it disappear.


----------



## Chris-PA (Jan 16, 2015)

tree monkey said:


> I just spent 2 hr's typing the longest post of my life, on a broken keyboard, with one finger, only to have it disappear.


Sounds like you were using an iPhone.


----------



## nmurph (Jan 16, 2015)

tree monkey said:


> I just spent 2 hr's typing the longest post of my life, on a broken keyboard, with one finger, only to have it disappear.



I hope you are busy re-typing your thoughts, they are worth hearing.


----------



## Hedgerow (Jan 16, 2015)

spencerpaving said:


> so you've seen my race sled then... I had a year where I was sprayin a little too lot and blew head O-rings on every run


I have... Blow or no, that sucker is impressive... Ski's are optional, as they never touch the ground!!!


----------



## Metals406 (Jan 16, 2015)

tree monkey said:


> I just spent 2 hr's typing the longest post of my life, on a broken keyboard, with one finger, only to have it disappear.


Serves ya right fer tryin'!!

[emoji14]


----------



## Mastermind (Jan 16, 2015)

tree monkey said:


> I just spent 2 hr's typing the longest post of my life, on a broken keyboard, with one finger, only to have it disappear.



That sucks. 

We just missed out on some education. 



nmurph said:


> I hope you are busy re-typing your thoughts, they are worth hearing.



You can say that a few more times.


----------



## Hedgerow (Jan 16, 2015)

Mastermind said:


> That sucks.
> 
> We just missed out on some education.
> 
> ...


nmurph said: ↑
I hope you are busy re-typing your thoughts, they are worth hearing.
nmurph said: ↑
I hope you are busy re-typing your thoughts, they are worth hearing
nmurph said: ↑
I hope you are busy re-typing your thoughts, they are worth hearing ↑
nmurph said: ↑
I hope you are busy re-typing your thoughts, they are worth hearing.
nmurph said: ↑
I hope you are busy re-typing your thoughts, they are worth hearing.


----------



## Mastermind (Jan 16, 2015)

Thanks Matt. 

You are a true and dear friend.


----------



## nmurph (Jan 16, 2015)

Mastermind said:


> That sucks.
> 
> We just missed out on some education.
> 
> ...




That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, That, 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Is that enough?


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## Mastermind (Jan 16, 2015)

Oh Lawd.....

YOU'RE FIRED !!!!!!


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## nmurph (Jan 16, 2015)

Thanks, Donald.


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