How to replace rings in poulan?

[countryhick]

Hi all
I have an old Poulan 3400. It has been getting harder and harder to get started and keep running over the years, so I was getting ready to toss it. I started reading the posts here and you guys got me enthused to resurrect it.

I checked the compression and got 90 lbs so I ordered a set of rings and a gasket kit. I cleaned the old saw up and disassembled it. I did not notice any tabs or anything on the piston to locate the gaps in the rings. Do You just stagger the gaps on opposite sides? Is there a trick to get the cylinder to slide over the rings? Do you need some kind of ring compressor?

I have tried to search the posts for answers, but my slow dialup finally wore me down so I am asking here.

Thanks

Jon

 

[logging22]

Hi all
I have an old Poulan 3400. It has been getting harder and harder to get started and keep running over the years, so I was getting ready to toss it. I started reading the posts here and you guys got me enthused to resurrect it.

I checked the compression and got 90 lbs so I ordered a set of rings and a gasket kit. I cleaned the old saw up and disassembled it. I did not notice any tabs or anything on the piston to locate the gaps in the rings. Do You just stagger the gaps on opposite sides? Is there a trick to get the cylinder to slide over the rings? Do you need some kind of ring compressor?

I have tried to search the posts for answers, but my slow dialup finally wore me down so I am asking here.

Thanks

Jon

Be patient grasshopper. Some of the poulan guys will be here shortly. Welcome to AS. Enjoy.

 

[OhioGregg]

countryhick,
Yes, they do have locating pins on the 3400 pistons. On top of the piston you will see an arrow and the the letters EXH. That is the exhaust side.
The pins are on the intake side, one on each side of the intake port.


Gregg,

 

[FATGUY]

countryhick,
Yes, they do have locating pins on the 3400 pistons. On top of the piston you will see an arrow and the the letters EXH. That is the exhaust side.
The pins are on the intake side, one on each side of the intake port.


Gregg,

:agree2:

 

[logging22]

Told ya.

 

[OhioGregg]

Here is a pic of a couple Poulan pistons, left one is a 3700 right is a 3400.
Can't really see them on the 3400 in this pic, but take my word, they are there..LOL
They sell a plastic ring compresser kit, Bailey's or many places. Makes the job easier, but the first one I did, I used a thin brass strip formed around the piston to squeez the rings together. But the tool is much easier.

Gregg,

 

[FATGUY]

say greg, do you happen to remember what the ring gap should be on a 3400? I just picked up another one and it only had 100#. The jug and piston look great, when I checked the ring end gap, it was about 1/8th of an inch!!!

 

[OhioGregg]

say greg, do you happen to remember what the ring gap should be on a 3400? I just picked up another one and it only had 100#. The jug and piston look great, when I checked the ring end gap, it was about 1/8th of an inch!!!

Geez Nik, can't help ya with that one, I don't think I ever heard what there suppose to be, but that does sound mighty wide.

I think for a REAL answer to that, one needs to consult with the Master..ModifiedMark!!!


Gregg,

 

[wigglesworth]

say greg, do you happen to remember what the ring gap should be on a 3400? I just picked up another one and it only had 100#. The jug and piston look great, when I checked the ring end gap, it was about 1/8th of an inch!!!

Come on Nik, I would expect more out of a machinist. You really mean "The ring end gap was about .125"

 

[pioneerguy600]

Mark or anyone else can correct me here but usually 9-10 thou. is what I look for when reringing a piston with new rings. I check the gap with the ring squared up in the bore above the transfer ports. Even 10-12 thou. up there is acceptable on a used saw as there will be a little more wear where the rings normally travel on a used cylinder.
Pioneerguy600

 

[FATGUY]

Come on Nik, I would expect more out of a machinist. You really mean "The ring end gap was about .125"

I feel shame

 

[OhioGregg]

Come on Nik, I would expect more out of a machinist. You really mean "The ring end gap was about .125"

LOL, I agree ! About an 1/8th. of an inch, sounds like my barnyard measurements. Thats about as small as I can measure anyway. :hmm3grin2orange:


Gregg,

 

[FATGUY]

not to hijack the thread farther,, but yeay Jerry, I agree. Andyshine77 even suggested that those might have not even been the correct rings?

 

[OhioGregg]

Come to think of it, Back when Brad was giving his 4000 a going over, there was some mention of ring gap. He was suprised at how wide it was as I recall.
I think these Poulans have rings that butt up to the pin, and not around it like some do.


Gregg,

 

[Modifiedmark]

Come to think of it, Back when Brad was giving his 4000 a going over, there was some mention of ring gap. He was suprised at how wide it was as I recall.
I think these Poulans have rings that butt up to the pin, and not around it like some do.


Gregg,

Exactly, you hit the nail on the head. Look at the picture that you posted and you can see how the pin takes up the whole groove and the rings do indeed butt up to them.

 

[JohnnyBoy1986]

just take your time on the disassembly its pretty much self explanatory, the ring compressor kit from bailey's would really help you out, i'd recommend it. get you a good set of rings, or if you wanted to go big and pick up a P&C kit i dont think they are all that much money anymore. there are many options for you, but the rings and gasket set would be cheapest, good luck with the rebuild.

 

[Fish]

The couple of manuals I have do not put out a ring gap spec for this saw,
just recommend replacing if the compression is low.

 

[countryhick]

Thanks for the replies and the picture is great.

I disassembled the saw and removed the old rings and then temporarily put it back together as I am still waiting for the new rings and did not want to forget how.

I saw some mention in the posts on this discussion site about crank seals leaking, could they be part of the problem? The gasket set I have has a new pair of shaft seals, but I thought I would not replace them. I was thinking trying to go that far might be a little difficult for me as I have never torn a chainsaw apart before.

Does it make sense to just try the rings first?

thanks
Jon

 

[Modifiedmark]

Thanks for the replies and the picture is great.

I disassembled the saw and removed the old rings and then temporarily put it back together as I am still waiting for the new rings and did not want to forget how.

I saw some mention in the posts on this discussion site about crank seals leaking, could they be part of the problem? The gasket set I have has a new pair of shaft seals, but I thought I would not replace them. I was thinking trying to go that far might be a little difficult for me as I have never torn a chainsaw apart before.

Does it make sense to just try the rings first?

thanks
Jon

No not to me it don't. Thoses seals could be up to 30 years old and hard as a rock. I would change them since you already have them.

I will say that those seals are pretty small and kind of tricky to change.

Check around and see if you have a local shop that would change them for you. If you have the saw apart where all they have to to is pop the old ones out and put the new ones in they shouldnt charge much and it would be a good investment.

 

[brokenbudget]

Thanks for the replies and the picture is great.

I disassembled the saw and removed the old rings and then temporarily put it back together as I am still waiting for the new rings and did not want to forget how.

I saw some mention in the posts on this discussion site about crank seals leaking, could they be part of the problem? The gasket set I have has a new pair of shaft seals, but I thought I would not replace them. I was thinking trying to go that far might be a little difficult for me as I have never torn a chainsaw apart before.

Does it make sense to just try the rings first?

thanks
Jon

if you have the seals, use them. the old ones are probably leaking slightly anyway.
be real carefull not to shave the seal when installing them over the crank. i like to wrap a small strip of electrical tape over the step on the crank (clutch side) to stop the sharp edges from ruining the seal. and make sure the seal and crank are lubed well.
you might notice a little bearing play, it's pretty well normal for a needle bearing crank to have a little play in them. thats why you want the seal to be plyable and flexable, so it seals against any movement the crank does.
have fun, they are a really good saw.