Reducing Squish on a Poulan Clamshell

[Chris-PA]

What size is the 2900 in displacement?

It's the same 46cc saw as yours.

 

[bikemike]

Well it's been a couple of weeks but the snow has finally melted enough that I could get to a wood pile, I'm mostly over the cold I had and it isn't pouring rain - which meant I could try out the saw a bit. In the mean time I got a new GB bar for it:
View attachment 412135

This bar is supposed to be 18" but is actually a full 19" from the case installed (19.5" with the chain), which is pushing it for a 42cc saw. The chain is 91VXL.

I don't like to waste wood cutting cookies so I noodled a few instead. I'm really pretty happy with this saw - it's got guts. This is noodling white oak with a knot, almost full bar:

It's working pretty hard but I think it's decent given the bar length.

Also, it illustrates how stupid the Piltz stuff is! This heavily modified 42cc saw can actually pull this bar with lo pro, but no way a smaller saw can handle a longer bar.

It's the same 46cc saw as yours.

If your looking to pipe your saw dont do what i did with the pocket bike pipe. Get one for a go ped they are very nice

 

[Chris-PA]

Here was my 46cc:

 

[bikemike]

I likke all the vids coming up

 

[bikemike]

This here is 10 times the pipe than what i have it is for a go ped and will let a saw screem with a broad power band especially for big or hard wood

 

[LegDeLimber]

I keep thinking about something like that ,tucked in around my leaf blower.
Got room for a nice glasspack end can. and it would have to be close to the moded mufler on it now, noisewise. Actually would preffer to get the DBs a bit lower and carrying a couple extra pounds on a backpack wouldn't be that big of a deal to me.

The power band would have to run from no higher than 5000-ish to around 7500~7800 rpm.
ah but seems I've so many more ideas than dollars nowdays.

 

[old guy]

What size is the 2900 in displacement?

46cc

John

 

[Chris-PA]

Another video - I wanted to try it out with a more typical bar length rather than the oversized GB bar. This is a bar from a McCulloch that is supposed to be 18", but is actually 17". I got it on a used saw and had to modify it so it would oil, otherwise it was similar to an A041 mount bar. It's 60DL rather than the 62DL typical on Poulans. The chain is WodlandPro (Carlton) lo pro.



I'm really happy with the way this thing runs. I put the GB bar back on it after a while and have decided that it pulls the longer bar just fine, and oils it well, so I'm leaving that on. I have other lighter saws to use the shorter bars on.

 

[Moparmyway]

NICE !!
She handles changes in load very well !!!

 

[drf255]

Chris, that saw runs great!

Good luck with it.

 

[old-cat]

http://www.ebay.com/itm/GO-PED-HIGH...167?pt=LH_DefaultDomain_0&hash=item3a93579abf

 

[Chris-PA]

http://www.ebay.com/itm/GO-PED-HIGH...167?pt=LH_DefaultDomain_0&hash=item3a93579abf

Neat, but this is a real working saw - it's the one made out of pieces of various saws that doesn't have a case or a place on the shelf. It sits on the floor of the shop, and consequently it's the one that gets picked up most often. Besides, the port timing isn't set up for a pipe, and if I wanted to do that I'd have to go and read all those 2-stroke tuning books that don't apply to saws!

It sure is cool looking though!

 

[old-cat]

Neat, but this is a real working saw - it's the one made out of pieces of various saws that doesn't have a case or a place on the shelf. It sits on the floor of the shop, and consequently it's the one that gets picked up most often. Besides, the port timing isn't set up for a pipe, and if I wanted to do that I'd have to go and read all those 2-stroke tuning books that don't apply to saws!

It sure is cool looking though!

Perfect for a little top handle saw!!! HaHaHa

 

[Chris-PA]

So how long will the 3D printed inserts last? Longer than I expected, but not forever:


Actually I figured they would fail immediately, and they held up for quite a few tanks. This evening I was noodling up some oak knots, and it ran great. I set it down and picked it up and restarted - it started, bogged, and a thick white cloud of smoke came out the muffler. It stank like heck too. I was pretty sure what it was!

It looks like one of the plastic parts pulled up, and then it cleaned off all the rest. The epoxy pulled off completely. The piston, cylinder and ring look ok but will need the junk cleaned off. Epoxy and PETG plastic aren't really appropriate materials for inside the crankcase of an internal combustion engines.

Now I have to decide what I'm going to do. The thing ran so nice I don't want to give up anything, but I doubt I will put it back the same way. I don't really think the volume reduction was that effective, but I do think the fillers helped direct the pressure wave off the front of the counter weights up the transfers. I have another idea about that I want to explore.

 

[Paragon Builder]

I'm interested in your idea! But in the meantime maybe put it back together to see the difference those made??

 

[Chris-PA]

I'm interested in your idea! But in the meantime maybe put it back together to see the difference those made??

I should, but that may be more work than I want to do. I really liked the way this saw ran.

I'm not sure I'll do the other idea, as I was just considering that turning new inserts out of aluminum on the lathe would be pretty easy. Just turn an appropriate bevel onto a disk, then part it into a ring and cut it into two inserts. Probably epoxy would be ok holding aluminum to aluminum.

 

[smokey7]

The clamshells i did poulan 3314 and eager beaver. I made a new lower pan with a cmm machine and a program on the cnc. I moved up the bearing pockets up.050 and and welded a .020 popup. I dont know what the port timing, is just it now blows 227psi with .019. Squish now and runs a 18" bar no problem. I widened
exhuste 2mm per side with no transfer tining change. Just lightly trimmed. It now runs with 4816 and a pp5020. neck and neck with a hot 350. Someone know why that works so well? She now 4 strokes hard at 14800- 15200 which i barely could 10500 before.What u guys think. Both of these saws have almost 10-15 gal of mix at 40:1 with 93 premium no ethanol..

 

[drf255]

Wouldn't welding a popup piston just be easier Chris?

I'm intrigued by your work, for sure. It just stinks that it only lasted that long.

I'd be glad to weld a piston up for ya, just say the word.

 

[bikemike]

With a goodheavy mix these saws will run forever. when youreduced squish050 inch you may want to consider running up the ports 050 inch so you get your port timing back. but then again the smaller transfer opening may be why its running great by forcing the new fuel air mix to the top of the cylinder with less mixing of spent gasses

The clamshells i did poulan 3314 and eager beaver. I made a new lower pan with a cmm machine and a program on the cnc. I moved up the bearing pockets up.050 and and welded a .020 popup. I dont know what the port timing, is just it now blows 227psi with .019. Squish now and runs a 18" bar no problem. I widened
exhuste 2mm per side with no transfer tining change. Just lightly trimmed. It now runs with 4816 and a pp5020. neck and neck with a hot 350. Someone know why that works so well? She now 4 strokes hard at 14800- 15200 which i barely could 10500 before.What u guys think. Both of these saws have almost 10-15 gal of mix at 40:1 with 93 premium no ethanol..

 

[smokey7]

It ona a test that wemt well. I am very happy with it. I ended up with tons of torque and good holding revs in cut. I sure can lean on it. If i i run it piss revving it i am sure its blowing raw fuel out the exhuste probable from my huge exhuste opening. I am thinking about adding bafels or a pipe for fun to let it.pull some of the raw back into engine. Its a meg gas guzzler it burn way more fuel then my hot 630. Maybe twice as much as a compairson.