044 puzzle

[Mac]

I goofed and committed to buy a piston & cyl for my 044. Turns out it takes a 12mm wrist pin and I've got the 10mm. I've got one guy saying I just need oversize pin bushing to make 12mm piston work with 10mm pin and another saying if I redo top end, bottom end will fail, and one more guy says no worries with bottom end. What do I believe? Any unbiased help with this and other unforseen problems would be appreciated. All 3 guys have saw shops!
Mac

 

[ktoom]

I actually need 2 new topend's for my 044's. I have herd that if ya just do a short block rebuild then the bottom end will eventually fail. Which makes sence since your gonna have a new jug and piston with old crank, old bearings, old seals and old gaskets. Whats to say something isn't leaking in the bottom end? Then again i have herd guys who just did topends and the're saws r still runing good. I opted to buy a new MS-440 cuz i didn't wanna have a saw that was half fixed.

 

[PA Plumber]

ktoom,
What did your ms 440 run? I am still kicking around getting one, but I had to have some shoulder surgery recently and now I'm looking at about 3 months before I can run a saw. I have been buying PPE gear but the saw will have to wait.

 

[Four Paws]

On a pro saw, you should get 2 to 3 top-end rebuilds before you have to get into the crank. AFAIK, the older models used the 10mm piston pin diameter. They upgraded to the 12mm for more beef. Installing a 12mm piston (if it is possible with some Stihl supplied bushings) won't make your crank fail.

 

[ktoom]

I paid $600 plus tax($642)for just the saw without a bar or chain.

 

[ktoom]

I would still make sure your crank is okay and doesn't have too much play in it. Also see if when u move the rod, it doesn't feel like nothing is ketching. I say that cuz i checked my crank on my newer 044 and the rod bearings r whooped, so now i gotta get a new crank. If it didn't have that problem, i woulda just put a topend on it.

 

[tek9tim]

Negative on the bushing. Doesn't exist. But to toss some ideas around, you can get an aftermarket 10mm pin piston, and perhaps run it in the cylinder you have. Big maybe not though, it seems to me they changed the size of the cylinder bolts along with the beefier bottom end. Also, not long after the 12mm change, they widened the ports, and in doing so had to move the ring locating pins further apart to avoid the intake, and I am not sure if the aftermarket pistons take that into account, or if they have the same specs as the original 10mm pin pistons. Hmm... lots of rambling. I'll sum it up: the 12mm piston is useless to you. If you buy an aftermarket piston, you might be able to use the cylinder you have. Or, you can do like I did, buy a 440 bottom end (from cheapstihlparts) and swap everything over.

 

[Lakeside53]

Yep, I'm with Tek9sim on this one...

 

[Freakingstang]

I'm seeing it as his saw has a 12mm pin and the piston he bought has the 10mm pin....

Can't help on the bushing, never seen or heard of one.

They also beefed up the cranks on the newer big pin units, from what i have read.

 

[Mac]

I have the old 044 with 50mm piston and 10mm pin. My inlaw ran saw hot and now cyl is scored badly. I knee jerked and committed to buy 12mm style without knowing. I can get a new crank with 12mm rod fairly cheap and will just go that route as I don't have time to be wrong again. I just worry now about what was said earlier concerning cylinder fitting crankcase and crank fitting case also. If there are any more bumps in the road with the 12mm piston setup, please advise.
Thanks again, Mac