Mainemechanic
ArboristSite Lurker
Screw older I'm 23 and I don't want to carry something like that around haha. But it was a vintage saw from 1982. All steel and such.
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Performance questions
- Thread starter Mainemechanic
- Start date
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There is no replacement for displacement. 50-60cc saw is a good all around saw.
Mainemechanic
ArboristSite Lurker
People say that but then you have 1000+ HP sub 2 litre cars everywhere. I'm planning a honda k20/k24 hybrid turbo build for next year that will make 700hp on pump gas at 2.3 liters All for under $2000 + the car. Obviously we are not talking forced induction on the saw but my point is there is locked up power in every powerplant, be it combustion engines or electric motors or what ever and small changes can help pump out that power. However I would still like a nice saw haha.
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Some designs just isn't made for it, slight changes but not much.
Steve
Steve
Mainemechanic
ArboristSite Lurker
That's half the fun is making things that where never intended to have lots of power have way more than you need, like a honda element which is what I'm going to build next fall. Haha. I love sleepers, saws are no different, I'd love to hide a nice 60cc powerplant inside this little poulan and tell people it's stock.
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Chris-PA
Where the Wild Things Are
Yeah, I was not paying proper attention, it is likely 42cc. Look at the EPA sticker at the back, it has the real displacement.
There is a lot of debate about dual vs. single ring pistons. I kinda like dual but it's not worth getting a new piston for. Single may rev better. Stock Poulan P&C will be 0.030" to 0.040" squish, and they can run well that way. Especially the older design cylinders with smaller combustion chambers. The dual ring piston I got looked like it would be around 0.050". I have a good cylinder and may build a dual ring one day, but I would be cutting the cylinder anyway - and I have no use for it at this time since mine run very nicely as-is.
Mainemechanic
ArboristSite Lurker
I am going to buy a new piston as there is some minor scoring on mine as well as really bad carbon buildup and for $15 and a saw that's already in pieces, might as well. But now I am thoroughly confused because after reading the threads about the displacement on these saws i looked up the part manual for my saw (correct type) and the number it gives me for the piston is for the 41.1 mm bore but I just measured my piston and it is 38mm. The EPA sticker was missing when I got it. The side cover says 2.0ci but that works out to 32.7cc. Obviously my measurement is what I'm going to believe but now I'm wondering if I was going to buy a P&C anyway couldn't one buy a 41.1 mm bore P&C and bolt it together? They share the same crank and conrod as I understand it. Is the clamshell on the bottom the same size?
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Chris-PA
Where the Wild Things Are
I disagree. These saws can make more power than you think. Give it some basic intake and exhaust port mods, plus some cutting on the bottom of the piston, and a muffler mod, and it will run very well.
Mainemechanic
ArboristSite Lurker
That's a nice looking piston, I was just sitting here looking at mine working out what I was going to shave off. Haha. Do you use a regular angle grinder? I took 3 years on machining and weld/fab class but I have no proper machining tools, right now I don't even have a caliper for precise measurements. I'm going to buy a cheapie this week tho
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Chris-PA
Where the Wild Things Are
There were only two displacements made, regardless of what's on the side labels. It's either 41mm/42cc or 38mm/36cc. Well I lie, there was a 3rd but I'm not say what that was - they're uncommon and I still hope to find one!
Everything is the same but the piston and cylinder.
Chris-PA
Where the Wild Things Are
Make sure you keep the piston ring end out of the intake port - on older design cylinders the ring never gets that low.
No right angle anything - I have 2 cheap Harbor Freight knock-off Dremels! One is tiny and has a motor for an electric toy with no front shaft support, I think the kit cost $10. There are things I can't do, but if one is determined.....
Mainemechanic
ArboristSite Lurker
That's another thing I need is a dremel! Damnit. The list just always gets longer.
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Mainemechanic
ArboristSite Lurker
I do have the older style cylinder, haha I snapped my ring in half a few minutes ago trying to test fit the piston to see what type of room I have on the bottom of the exhaust port, I put it in backwards and the corner caught the exhaust port because the piston was in backwards. Good thing I'm going to get a piston kit in the morning anyway haha. Teach me to pay attention.
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schmauster
Secret ArboristSite Operative
What I did as far as airflow
widening on the exhaust port (just expanded the sides a little) doing this as a learning tool for porting expensive saws.
muffler modded (maybe 80% more)
Widened the narrowest part of the carb, maybe 15%
Cut the plastic restriction plate off at the intake of carb from filter
Gasket matched things a little. Left the ports rough.
Pretty much removing any obvious flow restrictions. A bit of experience wrenching on saws, no experience porting 2 strokes. Ive been doing fuel injection and turbo systems for a little bit.
widening on the exhaust port (just expanded the sides a little) doing this as a learning tool for porting expensive saws.
muffler modded (maybe 80% more)
Widened the narrowest part of the carb, maybe 15%
Cut the plastic restriction plate off at the intake of carb from filter
Gasket matched things a little. Left the ports rough.
Pretty much removing any obvious flow restrictions. A bit of experience wrenching on saws, no experience porting 2 strokes. Ive been doing fuel injection and turbo systems for a little bit.
schmauster
Secret ArboristSite Operative
Hit me up and I can post some pictures, i should still have them.
More power, go back to a sprocket nose bar. And a sharp chain.
Link is a parts diagram - ipl
http://s30387.gridserver.com/partsDiagrams/Poulan 2075.pdf
Attached is a service manual.
Link is a parts diagram - ipl
http://s30387.gridserver.com/partsDiagrams/Poulan 2075.pdf
Attached is a service manual.
Consider buying the whole p/c combo from China, bolts right on, runs fine and is CHEAP
https://www.arboristsite.com/community/threads/cheap-fix-for-dead-cheapie-poulans.308102/
On these small displacement engines, a sharp chain is by far the most important thing you can do to increase performance. Watch the raker height as well and you’ll be cooking with gas.
Mainemechanic
ArboristSite Lurker
So I stayed up to late and got my saw together, enough to run it anyway. I'll put the bar and cover on in the morning after I double check it on fresh eyes. I swapped in a 42cc P&C from a craftsman I got a deal on today(2 of them for $20!), I wanted to use the craftsman chassis just because I like that it's all black, I probably will swap it eventually but the fuel lines where all rotted and the clutch was rusted all to hell. The guy thought it was blown up but I gave it a good yank and it turned over while turning the chain and I knew it was the clutch. So I didn't even get the crank out of that saw just stole the P&C. So I swapped the P&C, cut the piston, (I forgot to take a picture, however it was mild) ported the intake and carb mount mildly, and opened the exhaust port up pretty good on the top and sides. I used the walbro that came on the poulan for now just because I need to cut wood tomorrow and I know it's clean. This thing already sounds like twice the saw it was a week ago! Got a nice 18" bar with the craftsmans but the chains not the best so I'm going to run the 16" tomorrow! Excited to tune this thing and rip some wood! I made a first start video but can't upload it and I don't have a YouTube account.
On a side note all the extra airflow I gave this thing is going to lean it out so I will have to enrich it correct? More air=more fuel(and my personal favorite, oil!) That's my train of thought on that...
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On a side note all the extra airflow I gave this thing is going to lean it out so I will have to enrich it correct? More air=more fuel(and my personal favorite, oil!) That's my train of thought on that...
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