Author Topic: Poulan 3500/3750 mods  (Read 744 times)

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Offline The Ripper

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Poulan 3500/3750 mods
« on: November 02, 2022, 09:53:00 pm »
 Found this mod write-up for the 3500/3750 using a stihl 039 piston and cylinder mods and thought I'd pass it along cause I've
 ordered all the parts to tackle this mod ( I'm using the Cross Pop up version) to boost the get up in my 3500  to pull a 24" bar chain.https://opeforum.com/threads/poulan-380-3750-stihl-039-390-piston.19141/

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Offline The Ripper

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Re: Poulan 3500/3750 mods
« Reply #1 on: November 05, 2022, 05:21:32 pm »
Got my piston today and it's top-notch quality I'm really impressed.The piston by itself weighs 62 grams, pop-up is about .035 and all other dimensions are correct with this youtube build. This saw with a G/D and .017 off base only put out 125 PSI, so I'll be doing some calculating on proper gasket thickness for .025 squish. Tried posting image but no go.


Offline The Ripper

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Re: Poulan 3500/3750 mods
« Reply #2 on: November 11, 2022, 11:07:20 am »
Piston headed to Tennessee for machining. With what I took off the cylinder base Which I think was around .010,I need a base gasket
with a thickness of .030 for a .025 squish which I'll have to make and will probably change a bit when the gasket is compressed.

Offline 3000 FPS

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Re: Poulan 3500/3750 mods
« Reply #3 on: November 13, 2022, 11:58:23 am »
Got my piston today and it's top-notch quality I'm really impressed.The piston by itself weighs 62 grams, pop-up is about .035 and all other dimensions are correct with this youtube build. This saw with a G/D and .017 off base only put out 125 PSI, so I'll be doing some calculating on proper gasket thickness for .025 squish. Tried posting image but no go.



So are you saying you took .017 off the base of the cylinder and you only got 125 psi on the compression.
PP 505, 475, 445.

Offline Cut4fun

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Re: Poulan 3500/3750 mods
« Reply #4 on: November 14, 2022, 07:34:04 am »
I've had 3450 3750 pull 180psi stock with stock piston with base gasket. 

Offline The Ripper

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Re: Poulan 3500/3750 mods
« Reply #5 on: November 14, 2022, 11:41:49 am »
Got my piston today and it's top-notch quality I'm really impressed.The piston by itself weighs 62 grams, pop-up is about .035 and all other dimensions are correct with this youtube build. This saw with a G/D and .017 off base only put out 125 PSI, so I'll be doing some calculating on proper gasket thickness for .025 squish. Tried posting image but no go.


[/quote Yes and with a gasket delete( ,hot, cold made no difference on compression. The cylinder bore plating is in excellent condition and is piston skirts. Got nothing to lose
with this piston conversion, it was a cheap piston plus milling piston crown and pop up. Just wish I could of posted some images but that's ok

So are you saying you took .017 off the base of the cylinder and you only got 125 psi on the compression.

Offline The Ripper

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Re: Poulan 3500/3750 mods
« Reply #6 on: November 14, 2022, 11:46:57 am »
I've had 3450 3750 pull 180psi stock with stock piston with base gasket.

My luck always seems to run bad with getting a saw with decent compression, it's real obvious pulling the recoil .It ran ok just not enough oomph for 60CC

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Re: Poulan 3500/3750 mods
« Reply #7 on: November 14, 2022, 12:05:48 pm »
I have quite a few of the 3750 and 3500 poulans that I have modified and getting more compression was never an issue. 

There had to be something else going on with the rings.   If that squish is down to .025 or less, then I would expect to see at least like Kevin mentioned around 180 psi or more. 

I know the ones that I modified would run circles around the Stihl 036's that I have.   
PP 505, 475, 445.

Offline The Ripper

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Re: Poulan 3500/3750 mods
« Reply #8 on: November 14, 2022, 02:33:32 pm »
 But new rings in and yes they're very good saws that most just overlook. I know my gauge works because I have a Partner R16 blowing 185+ with new piston and rings. Anyway got new crank seals,new custom piston with dual rings and hopefully it'll build some good compression. one other thing to mention, there this guy that runs Lawnmowerpros.com where I got my genuine husky seals#530019146
I bought four don't know how many he has left over for 5.99ea + shipping plus bought those ebay seals. He's not that great at communications returning calls and has some bad reviews on BBB but I did receive my order so that's a plus and would do business  with him

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Re: Poulan 3500/3750 mods
« Reply #9 on: November 14, 2022, 04:09:43 pm »
But new rings in and yes they're very good saws that most just overlook. I know my gauge works because I have a Partner R16 blowing 185+ with new piston and rings. Anyway got new crank seals,new custom piston with dual rings and hopefully it'll build some good compression. one other thing to mention, there this guy that runs Lawnmowerpros.com where I got my genuine husky seals#530019146
I bought four don't know how many he has left over for 5.99ea + shipping plus bought those ebay seals. He's not that great at communications returning calls and has some bad reviews on BBB but I did receive my order so that's a plus and would do business  with him again

Thats retail price I sale them at too. Just had another 40 come in when I was down to my last 7.



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