More bad luck

[Brmorgan]

Yeah I love hand tools as well but I will draw the line at cutting up a log manually.

Even though I'm legally deaf I don't like the sound of powertools either, but it's more things like angle grinders and electric planers and sanders than set my teeth on edge and I wear the highest quality ear muffs and plugs I can afford if and when working with them. Maybe its because I grew up with chainsaws that I don't mind them. I respect all power tools but the one I respect the most (more than the 880) is my 12" table saw, that thing is a brute of a thing if its not treated right.

+1 on that; an angle grinder on thin sheet can put even my 090 at full throttle to shame. Most saws don't bother my ears all that much, but those little brushed Universal-style motors can be incredibly loud and ear-piercing.

I treat my tablesaw with about as much respect as a rabid pit bull. I've seen the results of way too many tablesaw accidents.

I don't think that many people would argue that a CSM is superior to a bandmill or swingmill overall; but they have their uses. I don't have equipment to move a 36" Fir deadfall log out of the bush, but I could easily chop it into 12" cants or something that I can manage with the quad. Also CSMing is certainly not the most cost effective form of milling, but it IS the most affordable to get started with, especially if you already have a suitably large powersaw to use with one - $500 could get you an Alaskan, a Mini-Mill, and a few other useful tools that will come in handy.

 

[TraditionalTool]

I respect all power tools but the one I respect the most (more than the 880) is my 12" table saw, that thing is a brute of a thing if its not treated right.

I have a 16" table saw with a 5HP direct drive motor. It's a Yates-American, built in the 40s. It is a machine to respect. It will take an 18" blade, but Yates recommended to use a 16"...

The table base is solid cast iron and weighs 1600 lbs. The table is scraped.

The problem with table saws and vertical bandsaws is that it's not so easy to leverage a large cant over them....on the arbor of a 5HP 3 Phase Louis Allis motor. Takes a minute and a half to spin down after you turn it off.

 

[Andrew96]

Well guys...we all mulled over yet again when we will choose a BSM, over a CSM...I myself can carry my CSM...I cannot carry the tree. It's cut where it falls...do that with your BSM. oke: The cost of a BSM in comparison, should include the cost of equipment to move a tree to be a fair comparison.

When I buy used equipment...I zero time them and then record fuel through them, if there is no other way to measure the use. That is usually just a going over but give it pistons and rings.
I threw out the 25 hrs before inspection number in the other post since I don't have a better one at this time (I use 25 hrs for air cooled, 30hrs for water cooled two stroke race machines). I'm hoping to see how Mtngun goes now that he has an hour meter on his setup and keeps quoting cut times in 'run hours'. So far my 25 hrs before inspection looks very conservative but I do feel counting running hours... is far better than material cut, and would rather open it up and match ring end gap to compression until I have a better number to work with.

 

[Sawyer Rob]

The cost of a BSM in comparison, should include the cost of equipment to move a tree to be a fair comparison.

Then, unless you are walking from your house with your CSM to the tree, YOU should include the cost of your car, van or pickup to get your CSM to the tree. One thing is for sure, either i'm moving that tree, OR you are moving your mill!

Ooooh you say you already have a car or pu? Well, i already have the means to move a log... And if it's TOO big, i can use my $50.00 Husky 55 to free hand split it so i can.

I've drug out more than a few logs with a pu, and even a couple with an old car.

DM

 

[mtngun]

When I buy used equipment...I zero time them and then record fuel through them, if there is no other way to measure the use.

I'm guessing you have a background in aircraft or nuclear maintenance, to have such excellent record keeping habits ?

I'm hoping to see how Mtngun goes now that he has an hour meter on his setup and keeps quoting cut times in 'run hours'.

I didn't anticipate using that hour meter feature but have to admit it is useful. Like BobL, I'm a dataholic. Anything that can be measured, should be measured. :biggrinbounce2:

 

[BobL]

Anything that can be measured, should be measured. :biggrinbounce2:

Yep - that's my day job so it comes natural for me to do this. I also have a number of different sensors that can be connected into a computer for data logging. And what I can't find in my shed I can often scrounge a loan of at work.

 

[Andrew96]

I'm guessing you have a background in aircraft or nuclear maintenance, to have such excellent record keeping habits ?

Geez...I guess it shows. :blush: Yup...irreplaceable antique aircraft. Lots of racing (bikes/cars), Fleet maintenance (for bikes which is different), Nuclear parts, Military parts. Lots of paperwork.
The game in all of those industries is quite different than managing your own equipment. I certainly don't run equipment like any of those industries. A failing part in those disciplines is death (well...lots of money, or lost history too). My failure is just money....
As for records for my stuff...that's easier than you think. But I do keep them. You and Bobl put yourself on the data collection crew....I'm over here interested in different data, while waiting for access to my porting software to correct the stupid 660 port timing I found after a full measurement. I just collect a little data. I'll pass on the cut times, cutter profiles. I'll read about them from you.

 

[mtngun]

A failing part in those disciplines is death (well...lots of money, or lost history too).

I understand. I spent some time working in a plant that made high liability products -- the chips for heart pacemakers, automotive anti-lock brakes, the controls in Boeing jets, etc -- every little move we made had to documented and witnessed, every little change had to be approved by a review board, etc..

waiting for access to my porting software to correct the stupid 660 port timing I found after a full measurement. .

Andrew, I am just beginning to get "into" the art and science of porting, particularly for the 066/660, so I'd love to hear what you have learned about the 660. Did you come to essentially the same conclusion as Timberwolf.

I love the 066/660. It's the Chevy Small Block of chainsaws. It's readily available, built like a tank, easy to work on, and lots of aftermarket and used parts are available. Yet it's practical performance -- the mid range power desired for milling -- is handicapped by scewball port timing and tame compression.

I was hoping that the 2nd generation BB kits would correct some of the port timing issues, but if I understand Grande Dog correctly, he RAISED the exhaust port on the 2nd generation jug.......

 

[Andrew96]

Andrew, I am just beginning to get "into" the art and science of porting, particularly for the 066/660, so I'd love to hear what you have learned about the 660. Did you come to essentially the same conclusion as Timberwolf.

Well maybe. I'm not going to draw any conclusions yet. I'm supposed to be quite good at developing 2 strokes with a broad torque curve and longevity. At least some people seem to think so and contract me for my opinion...well not in a few years now 4 strokes are everywhere. I'm "into" valvetrain harmonics now which is quite different. The 2 stroke history I have is also with a tuned exhaust, even way back with air cooled stuff we always had pipes to match ports and case volumes. These saws don't have one.....just a box!!!. Stihl put a perforated cover over the exhaust port to negate the negative wave, or any formation. That upsets everything. You think you're confused..that's baffling (literally too). If it's a one sided engine, like it looks to be...why the low compression? I've never plugged in specs for a 2 stroke without any pipe specs so until I (if I might say)...backwards engineer it. I don't understand why they did what they did. They seem to have every other detail well engineered. Right now I'm going to have to assume..they know more than me. Since I don't own the software I have to wait for a job before I have access to it. Until then..a little research and speculation is all I can do. I don't have any experience with saws but I think the limiting factor is it's air cooled, no variable exhaust port, not even a pipe!, can't change the head easily, so there is only so much you can do. I think it works amazingly well for it's displacement and porting...but there should be some more there without a pipe and the fuel I run. Well..who knows what anymore...it's not like I've ever seen a dyno curve for one, 1hp per ci (as advertised) is good but over such a small rpm. It would be fun to get some dyno time...don't know how I'd harness it though. Might have to be summer project.

I love the 066/660. It's the Chevy Small Block of chainsaws. It's readily available, built like a tank, easy to work on, and lots of aftermarket and used parts are available. Yet it's practical performance -- the mid range power desired for milling -- is handicapped by scewball port timing and tame compression.

I was hoping that the 2nd generation BB kits would correct some of the port timing issues, but if I understand Grande Dog correctly, he RAISED the exhaust port on the 2nd generation jug.......

Small block chevy syndrome is why I decided to hunt one down. I think of it to be more of a 80s smog small block though (small valves low lift/dur cam), the way it 'seems' to be setup.

I've read a lot of Timberwolfs posts. He seems to have developed his own model and has proven results. I'd expect to pay for all the work he did..and might go that route if I cannot work back to the same stock specs on my own.

I haven't tracked down Grande Dogs work yet, but will now you wrote his name out. I shouldn't really comment without reading up on what he did but many people go for earlier exhaust and rev it...it's good on some designs, easy to do, narrows the rpm band though. I like to target other areas first. Your BB kit looks to be a simple copy cat(from what I've read), too bad really. I was interested at first, until I read about your frustrations and it had the same porting specs. Watch out with these low compression thoughts...I've read your comments before..though in the case of the stock 660 I think it's a little low with the porting chosen. Good 2 stroke design has what you might call a variable compression ratio. At certain rpms the cylinder will get overfilled. On a 2 stroke the effective compression ratio is higher, unlike say a 4 stroke (nat aspirated) where it's usually always lower. Some call this on the pipe..the power band. It's not as cut and dry as simply..a low static compression. High compression with short timing isn't going to make torque. If their porting model shows a spike in VI at some RPM..they will have to keep the static down for you so you can run any fuel.

Ahaaa...Maybe they developed that BB kit from a generic porting model...I didn't think of that until I wrote all of the above. The model is just a bunch of best guesses and assumptions (some actual facts..but not unless you developed it yourself). You use the model as a tool..not a design, someone should have told them that.

 

[mtngun]

.Maybe they developed that BB kit from a generic porting model...

I'm pretty sure on the 1st gen BB, Bailey's just sent an OEM P&C to the vendor and said "copy this, except make the bore 2mm bigger."

To prevent the wider piston from hitting the crankcase, they had to shorten the skirt ...... which free ported the exhaust. A lot of people complained about that.

To cure the free port issue, the 2nd gen kit lifts the bottom of the exhaust port 2mm. I'm cool with that. But then they raised the top of the exhaust port 2mm, too, which concerns me, going by what Timberwolf says about 660 porting.

Since port work is new to me, I'm not the right person to say what's wrong and how to fix it. I'll just sit on the sidelines and watch, and hope a good deal comes along on a used 084/088/880 or 3120.

 

[Andrew96]

I'll just sit on the sidelines and watch, and hope a good deal comes along on a used 084/088/880 or 3120.

Free porting is basic...I haven't seen that on a manufactured engine in a very long time..though I don't do saws until my own...after market parts...I think I'd try to send them back. I have to admit that I didn't realize the 660 exh. porting was so short until after I hunted one down. I would have liked an 880 just for displacement (chev big block) but one never came along. I haven't looked at any problems with that setup either though. There certainly isn't an easy quick fix for the 660. I'm not used to a fixed head, no pipe and not many pistons to choose from.

No more time to read this morning but...I stumbled across your stepped dome post. I'd love full time access to a CNC BTW. I don't even have an NC at home so I have to work a bit harder.
A couple of points without hijacking the post. Your compression does seem really low..stupid low. Low enough to question and confirm. I thought I might suggest a couple of things...maybe you have tried them already. Low compression could = poor ring sealing (high exhaust aside). New rings won't seal worth their weight in a funny bore. Easy concept. However, have you measured your bore to see if it's really round? Is you piston really round? Rings won't seat riding a funny shaped piston. You can feed a standard bore gauge in and around the ports to see if it's really cylindrical. One reason why I hate using cast pistons. I've measured them changing shape after a couple of heat cycles. More than 0.001" change! I've seen cylinders that are all over the place, or dips if you'd like that could allow for poor ring sealing. I'm sure you've looked at end gap. What shape rings came with your BBkit? Crowned or tapered.... or can you run them upside down? Not all are marked.
One way to see if you are really getting a good seal is a wet compression test. I didn't see any figures you posted from a wet compression. Add some oil to your bore, nice wet walls and see if you get a better number. You will..but how much better? I use it as a quick and dirty method to determine if you should rering or not without measuring end gap.
Have you matched your compression tester to a known good gauge..or even another one? I'd expect you have done these little things but skimming...I didn't see the results. 5000' just isn't really that high enough to loose 30psi. (off the top of my head without tables).

 

[mtngun]

5000' just isn't really that high enough to loose 30psi. (off the top of my head without tables).

The quick and dirty rule of thumb is 3% per 1000 feet, so expect a 15% loss. If the average sea level compression is 150 psi (seems average for the 660), it would be down to 128 psi here (or 137 psi at Williams Lake, BC ).

I may have made some progress on the OEM jug's compression but want to put another tank through it before jumping to any conclusions.

I don't claim to know a durned thing about the physics of free porting, but just for the heck of it I may do a pop up on my old BB kit -- which would make the free port even worse -- and see what happens.

 

[Brmorgan]

The quick and dirty rule of thumb is 3% per 1000 feet, so expect a 15% loss. If the average sea level compression is 150 psi (seems average for the 660), it would be down to 128 psi here (or 137 psi at Williams Lake, BC ).

I may have made some progress on the OEM jug's compression but want to put another tank through it before jumping to any conclusions.

I don't claim to know a durned thing about the physics of free porting, but just for the heck of it I may do a pop up on my old BB kit -- which would make the free port even worse -- and see what happens.

Awww.... You thought of me! How sweet! :monkey:

LOL....

 

[Andrew96]

Well I have a lot more catching up to do to get to where you are, I can see. No sense going down a road everyone else has reviewed already. I did a quick review of my cylinder then put it back together to get milling (too excited). Glad you have a P/C to play with.
Free porting can be a leak of your collected charge (I'm sure you know) You'd like it packed into the case..hopefully more than the volume would dictate....but then after successfully overfilling the case...you let it go. Not only will you loose some of your charge, you could alter the flow direction, swirl, you could cool the wrong 1/2 of the piston creating funny wear problems, leave the piston unsupported, again, creating wear problems, ring flutter etc etc. The unburned charge out the pipe would reduce your header temp (well..there isnt' one here) but I'm sure it does offer some reflected wave. The exhaust would be nasty if you measured it so OEM can't do it..HP leaking out really. The increase in compression might offset some of this though. One little change effects everything..you can really only guess the outcome...then....expect to be wrong. Uncovering the port, loosing your charge, leaving your piston hanging just before you whack it with a spark is asking for trouble. This bad situation just might mean living with...altering your expected live time for that piston/ring. Change it and keep going.

 

[mtngun]

Yeah, I was just kicking ideas around....... having to rethink my plans since the 2nd gen BB kit is no longer a good option.

BTW, here's an excellent thread comparing the 660's screwy port timing to the BB's even screwier port timing. Martinm210's 660 port data

And some of his data. Note the BB exhaust port is higher and the top edge is flat instead of curved. Bad, bad, bad.

Numbers for 660 jug. I'm told the older 066 jugs had saner exhaust timing. The changes to compression and timing may be related to emissions.

Numbers for 1st gen BB jug. On 2nd gen BB, exhaust opens even sooner (2mm higher).

Sorry for hijacking your thread, Kicker. Any progress on the 880 ?

 

[Brmorgan]

Well after looking at those maps, I can see why a lot of folks say you won't see much if any for gains with the BB kit. The transfers are tiny in comparison! Is the exhaust port in the OEM port map stock though? If so, it's a fair bit different than the three cylinders I have here. They're much more squared off on the sides and look wider but I don't know for sure.

 

[mtngun]

Is the exhaust port in the OEM port map stock though? If so, it's a fair bit different than the three cylinders I have here. They're much more squared off on the sides and look wider but I don't know for sure.

Yes, the OEM is stock. His OEM specs are similar to what Timberwolf has posted pm another thread. Seems typical for 660 jugs. Supposedly the older 066 jugs had saner exhaust timing.

If you would post maps of those old jugs of yours............. then we could compare notes.

Here's Timberwolf's 660 OEM map.

 

[Kicker_92]

Not to bring this thread back on topic, but picked up a replacement used bottom end for the 385xp with a good crank. Will be in the process of swapping over parts this weekend, then hopefully back to milling again.

Without the alternate saw, I've been reluctant to setup the rails to start cutting another log. Will hopefully be able to resolve the surging problem on the MS880 now.

 

[Andrew96]

Kicker...good to hear you have a new bottom end going in so you can get out of the shop and start playing some more. It didn't sound like you changed your porting on the 880 enough to cause inversion.

Seems I cannot come to the party without a map of my '09 660. I'll have to do that and crunch some numbers. I did some measurements comparing to to TW dims but was only close. Maybe another small step was made to lower the peak cylinder pressure in an effort to reduce emissions...add service life via skirt support at the expense of BMEP? They could be worried about the restrictive 3/8" exhaust as well...let it bleed longer. Certainly isn't a lot of options with this type of cylinder (C + head all in one) and no pipe. It's quite limiting in what you can do. I was pleased with it's stock performance not ever even seeing a saw over 60cc before. (sheltered life I guess).
Too bad about the Gdogs BB kit change for R2....I think I'm up to speed on the BB now. I would have thought they would have made some changes on another run to lower the Ex duration and pick up some volume on the intake to cover the increased displacement, improve VI and make a torquer (if that was the goal), but I'm sure it came down the cost of altering the castings vs the number of C. sold. (afford only 1 change...right or wrong). With the R1 version, they may have tried higher intake velocity to cover the extra bore and volume with the smaller In. ports, Who knows if the angles were changed though. The early exhaust opening, with the long duration seems to require a large volume chamber to get it through. Without a pipe...I cannot imagine it getting a clean full charge. They certainly didn't intend on it being reved out when comparing In. volume to stock...yet they have lower compression...contradictory...or...longevity with the heavier piston?
Did ignition timing change between the 066 and the 660?

 

[mtngun]

I did some measurements comparing to to TW dims but was only close.

I believe TW merely used a pencil & paper port map to determine timing, not a degree wheel, though I could be wrong. Point being, a paper map is only approximate so you would expect a little variation from one person's map to the next.

Maybe another small step was made to lower the peak cylinder pressure in an effort to reduce emissions...add service life via skirt support at the expense of BMEP? They could be worried about the restrictive 3/8" exhaust as well...let it bleed longer.

Are you saying your 660 has even more exhaust duration that TW's ? How's your compression ?

Regarding the BB, Baileys has no engineering staff, and it's getting painfully obvious.that they are in over their heads. I wish them the best of luck, but I suspect they will eventually accept their limitations and retreat to more modest projects.

For example, instead of continuing to struggle with the 066 BB, it might be easier for them to make a carbon copy of a pre-emissions 066 jug. No engineering required, and there definitely would be a market for such a thing.

Speaking of which, I've been searching old threads for a port map of a pre-emissions cylinder, but haven't found one yet. Just anecdotal comments by Jacob and Lakeside to the effect that the old cylinders had more compression and less exhaust duration.

Did ignition timing change between the 066 and the 660?

Hmmmmm..... there have been changes to flywheels and coils, but I not sure about the timing numbers. Either Jacob or 04Ultra should be able to tell you, though.