Any NOS Poulan Countervibe 3400 Piston Rings!

[kmcinms]

You've been given all the answers.

Smells like something else to me. But, I get it, you must run a high performance engine shop and you're trying to impress a couple hillbillies on a chainsaw forum with your brilliant "answers". lol
I've blueprinted quite a few engines in the last 45 years, I do know how all of this works.
As far as I know there are at least two suppliers of rings the correct OD, and axial thickness without resorting to any form of trickery to get them to work, other than fitting the end gaps. One set is of known quality that comes from Italy, the other one, we're not certain of. Either set should work fine in these saws after proper fitting. No need to go crazy with it.

Good fortune.

 

[Highlander1959]

Hastings.

https://www.hastingspistonrings.com/wp-content/uploads/2020/07/diametrical.pdf

Thanks Bill. That's good info. Unfortunately, the 3400 piston diameter is under 2" and I don't see any small stuff there but I'll definitely keep them in mind.

 

[Highlander1959]

Smells like something else to me. But, I get it, you must run a high performance engine shop and you're trying to impress a couple hillbillies on a chainsaw forum with your brilliant "answers". lol
I've blueprinted quite a few engines in the last 45 years, I do know how all of this works.
As far as I know there are at least two suppliers of rings the correct OD, and axial thickness without resorting to any form of trickery to get them to work, other than fitting the end gaps. One set is of known quality that comes from Italy, the other one, we're not certain of. Either set should work fine in these saws after proper fitting. No need to go crazy with it.

Good fortune.

There's always one, isn't there kmc? Is there a block function on this site?

 

[Bill G]

Thanks Bill. That's good info. Unfortunately, the 3400 piston diameter is under 2" and I don't see any small stuff there but I'll definitely keep them in mind.

It would be best to call them. Years ago I talked with a woman there that extremally knowledgeable. She was top notch and they probably have more than they list.

 

[Old-Feller]

If you can get thicker rings lap them down. If you can't then take your piston to a machine shop to widen the ring groove. Cut the top of your land area not the bottom of the ring land.

What one will solve your problem if your not looking to use a -0.015 under or file fit down from +0.040 overbore sized rings?

You guys asking about pricing need to just stop. It is an antique not available for the past few decades. Get real.

Now what is your next excuse?
Metric sizes?

Check the depth by simply installing the ring backwards after you fit it to 0.0012-0.0009 installed clearance. Back clearance should be a minimum of 0.003 not to exceed 0.010 according to me not some number plucked from the sky or a manufacture. But, no wait, most rings are installed to those specs factory on just about everything made that burns fuel and has pistons with steel rings, how convenient.

You've been given all the answers.

What kind of machines are you holding these tolerances with mentioned in your sig line?

Tolerance is held to under 0.0006 runout

 

[Highlander1959]

Factory rings are .062 thick (axial height). What brand of rings did you buy?

Sorry for the late reply. I bought one set of rings from Lil Red Barn (no brand name on them) and put those in one saw, and I also bought a LRB unchromed piston kit with rings and put that in another saw. So far, both are working well for me. I didn't measure the rings that came with the piston but the other ones measured .061-.062 and fit the OEM piston grooves perfectly with plenty of meat on them to do a little filing and achieve the proper gap. Since then, I've found that Jacks has Husqvarna cylinders and pistons of the same part numbers as the OEM Poulan parts. I need to see those ...

 

[kmcinms]

Sorry for the late reply. I bought one set of rings from Lil Red Barn (no brand name on them) and put those in one saw, and I also bought a LRB unchromed piston kit with rings and put that in another saw. So far, both are working well for me. I didn't measure the rings that came with the piston but the other ones measured .061-.062 and fit the OEM piston grooves perfectly with plenty of meat on them to do a little filing and achieve the proper gap. Since then, I've found that Jacks has Husqvarna cylinders and pistons of the same part numbers as the OEM Poulan parts. I need to see those ...

What did you set the end gap to? I don't know anything about those, what are the part #s you're looking at?

 

[Highlander1959]

What did you set the end gap to? I don't know anything about those, what are the part #s you're looking at?

They list them by saw model number so if you search their site for Poulan 3400 rings, you should find them. They're the flat ended rings, just like OEM. I put them in the bore, used a piston to square them up, and found almost zero gap clearance. I removed them, then measured the width of the little locator pins in the piston grooves, and added 6 thousandths to that number. I started filing each ring a little at a time with a Dremel and putting them back in the bore to measure the gaps until I had each one gapped properly. I don't remember what my actual gap was but it was about .006 - .008 plus the pin width. A little large is better than too small. Too small would be disastrous as the rings would have no room for expansion. If you can't get the piston into the cylinder with the rings installed you KNOW the gap is insufficient and needs to be widened. In that case, I'd recheck my math or remeasure that guide pin width because the piston should go into the bore pretty easily if the rings have room to compress. Seeing as these engines use a double ringed piston with the gaps offset, it's OK if the gaps are a little wide. You might sacrifice some compression but that's preferable to destroying the piston and/or bore.

 

[kmcinms]

They list them by saw model number so if you search their site for Poulan 3400 rings, you should find them. They're the flat ended rings, just like OEM. I put them in the bore, used a piston to square them up, and found almost zero gap clearance. I removed them, then measured the width of the little locator pins in the piston grooves, and added 6 thousandths to that number. I started filing each ring a little at a time with a Dremel and putting them back in the bore to measure the gaps until I had each one gapped properly. I don't remember what my actual gap was but it was about .006 - .008 plus the pin width. A little large is better than too small. Too small would be disastrous as the rings would have no room for expansion. If you can't get the piston into the cylinder with the rings installed you KNOW the gap is insufficient and needs to be widened. In that case, I'd recheck my math or remeasure that guide pin width because the piston should go into the bore pretty easily if the rings have room to compress. Seeing as these engines use a double ringed piston with the gaps offset, it's OK if the gaps are a little wide. You might sacrifice some compression but that's preferable to destroying the piston and/or bore.

Sorry, I was asking about what part numbers for the Husky parts on Jack's small engine site.
As far as end gap goes, it should be .068 - .070. I've filed rings for countless engines, sorry for the confusion.

 

[Highlander1959]

No worries. Exact same part numbers as the Poulan numbers.

 

[kmcinms]

No worries. Exact same part numbers as the Poulan numbers.

that's what I'm asking. I don't have the part numbers handy.

 

[Highlander1959]

that's what I'm asking. I don't have the part numbers handy.

Piston kit is 530010314 and the cylinder is 530012066. Unfortunately, I just got the notice I feared from Jack's. "Order cancelled-part has been discontinued" ... I have no idea why companies leave these parts listed on their web sites if they can't get them