272 cylinder help

[ale]

I need to know what are the differences (if any) between the chainsaw (272xp) cylinders and the stump grinder (272s) and the cutoff saw (272k).
They have different part numbers but I’ve heard varying stories if they are the same or not. I have searched and asked several different people with no clear answer.
I have heard the “porting” is different.
I want to use this cylinder from a 272k for a project saw. Part number is (506260172). It’s a Mahle cylinder and the piston has two rings and windows.

 

[Roanoker494]

Stump grinders and cutoff saws normally have different porting and do not work so well on a chain. The porting effects their RPM range and power band.

 

[Boleclimber]

Read this thread. Post #4 reports the cylinders are the same part number.

http://www.arboristsite.com/chainsaw/45939.htm

I know 371k and 372xp has the same cylinder. Iw ould be surprised if the same did not hold true for the 272 series.

 

[ale]

Thanks...
I've read that thread and it's still not clear. Maybe the part numbers were the same at one point and then were changed. Still does not answer the question if the cylinder and piston themselves are the same. FWIW i've compared the other markings on the Mahle xp cylinder to the k cylinder and they were the same except for the last digit. One had something like xxx xx xx W3 and the other xxx xx xx W2.

 

[Boleclimber]

Post #4 of that the link posted.

"Actually by the IPL's that is the one of the few things that is the same. crank,piston.cylinder. The crankcase halves however carry a different part number as doe's almost every other part "

That is clear to me that the cylinder and pistons are the same.

 

[ale]

Post #4 of that the link posted.

"Actually by the IPL's that is the one of the few things that is the same. crank,piston.cylinder. The crankcase halves however carry a different part number as doe's almost every other part "

That is clear to me that the cylinder and pistons are the same.

It appears at one point the PN's were the same...but they have changed and are now different.

Can someone with a confirmed Mahle 272xp cylinder look at the markings on the bottom?
My cylinder from a 272k (506260172) has: MAHLE 52ZN22W5

I'm thinking Husqvarna at some point created seperate part numbers for whatever reason. But the cylinders and pistons from Mahle may all be the same. If the Mahle numbers match...that's good enough for me.

 

[Boleclimber]

I will be around (2) 272XP cylinders in about 2 hours. I will check the numbers and post what I record then.

 

[albert]

272xp's have 1 ring pistons, so pistons must be different.

 

[half_full]

got my 272 as a parts saw. cylinder is 52ZN22 W1? Doubt it's original to the saw. Piston has one ring. I have all the parts to assemble now. Just finishing up other small projects first.
Like this only I do not have a location for decomp

http://www.ebay.de/itm/ws/eBayISAPI.dll?ViewItem&item=120726626828

 

[Boleclimber]

My 1994 model 272 XP (no Decompression) has 52ZN22 W2

My 1996 model 272 XP (decompression release) has 52ZN22 W5

You wrote your 272K cylinder is MAHLE 52ZN22W5.

Sure looks the same to me.

You could always degree wheel both your cylinders.

 

[ale]

Thanks for the help. This looks like good news. The W? marking must have something to do w/ the decomp.

 

[lfnh]

272 xp w/ fact decomp 1996 wk 34 mahle 52ZN22 W5. Piston single ring windowed.

 

[IthacaMan]

It appears at one point the PN's were the same...but they have changed and are now different.

Can someone with a confirmed Mahle 272xp cylinder look at the markings on the bottom?
My cylinder from a 272k (506260172) has: MAHLE 52ZN22W5

I'm thinking Husqvarna at some point created seperate part numbers for whatever reason. But the cylinders and pistons from Mahle may all be the same. If the Mahle numbers match...that's good enough for me.

My 272XP is an early 1991, without decomp valve,single ring piston,and P# 52ZN22 W1.

 

[IthacaMan]

Just a guess,but could the "W" number be the casting mold number.Maybe that is why my early 1991 saw has a W1 and newer saws have a higher number?:confused2:

 

[ale]

other questions...
My piston has two rings w/ windows...should I look for a one ring piston for this build?
This saw will be ported. What are the pros/cons of one vs two rings?
Also, the cylinder is marked "A" on top and the piston "AB" Is this an issue? What should the tolerances be?

 

[IthacaMan]

I asked for help a while back with a stihl 024 rebuild and another member,cant remember his name,said that cylinders are marked A or B for the tolerance group they fall into.So an AB piston should be ok with either an A or B cylinder.Hopefully someone can varify this with Husky saws too.

 

[Boleclimber]

I have used mis-matched piston cylinder set ups with no issues. It all depends what the tolerances measure out at. To date, I have only needed to fit rings.

There is a thread somewhere about piston/ cylinder combinations as you describe. I remember reading years ago. I'll keep looking for it.


Below is a thread regarding a Jonsered 670 piston swap (50 mm bore). The tolerances are close for what a Husky 52mm bore uses.

http://www.arboristsite.com/chainsaw/144664.htm

 

[Boleclimber]

Another read:
http://www.arboristsite.com/chainsaw/125012.htm

 

[lfnh]

Another thread on Piston size grades fitting and clearance.
http://www.arboristsite.com/chainsaw/172937.htm