Cylinder Pitting

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Adirondackstihl

Flyz, Fuel & Fotos
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Weird? Happens only in the lower portion of the cylinder. No pitting above the top of the lower transfer. The PTO side bearing was just about to puke.....maybe another 2-3 tanks of fuel I figure. Would the deteriorating bearing cause that? I assume yes? I think I'm gonna run it....what do you think? Other than what you see in the pictures, everything else looks fine to me.

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what kind cylinder.... OEM, A/M? is the piston toast because of the pitting?

STIHL 044 10mm
OEM
Piston looks fine....thats what I dont understand. When I say fine, I mean it has the usual signs of use, but no reasons for me not to re-use it.

I've personally only ran about 10 tanks through the ole girl.....10 of probably VERY many before I got it.
Only thing I can think of is that someone had cleaned it before I got it?
I just dont understand. Saw was running perfect when I tore it down to replace fuel line and filter as a preventative maint type thing.
 
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Manufacturing defects? Stored in a humid environment and rust set in?
 
I would say that pits where in the jug from new. It the coating would have came off of the pit marks in the cylinder while the saw was running it would have nasty long vertical marks in the piston. Same thing would happen if it had bearing parts between the piston and the cylinder. Run some 500 or 600 grit paper across the pit marks to make sure it has no high spots and run it.

Later
Dan
 
I would say that pits where in the jug from new. It the coating would have came off of the pit marks in the cylinder while the saw was running it would have nasty long vertical marks in the piston. Same thing would happen if it had bearing parts between the piston and the cylinder. Run some 500 or 600 grit paper across the pit marks to make sure it has no high spots and run it.

Later
Dan
I agree - it looks like corrosion or casting defects to me.
 
I agree with you Dan.
The saw was blowing 175psi before I tore it down.
Even with the ring end gap WAY out of spec.

I'm just hopin to get it back together before Scott & Steves GTG.

Sounds like the 10mm wrist pin is on backorder through Northeast Stihl
 
Maybe someone was a little too aggressive with a ball hone on a past rebuild

You know, in all honesty, I dont think that cylinder had ever been removed from the base.
I guess I'll never know.

I'll rebuild her and run her till she sharts the bed...... :rock:

Then I'll have spare plastics and pieces for my other saw...."Christine II" :D
 
Is that a Mahle cylinder? I'm surprised to see pitting and poor beveling like that in an old 044.
I wondered about that too - my limited experience with cylinders is Poulan clamshells and Earthquakes - I've never seen anything that ugly.
 
I could be wrong, but I didn't think Stihl cast their own cylinders back then. I'm thinking that cylinder has been replaced before. Are the cooling fins on the top straight or angled?

Angled fins

99.9% sure its labeled as a STIHL cylinder.
I wont be 100% until I get home tonight.
 
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