Chainsaw Repair

Well, I'm messing around with an experiment turning a HVA 261 into a 262XP. I do not want to cut a new band and the 262XP does not provide enough clearance to run without a base gasket. Nominal squish with the gasket is 0.03275 base gasket is 0.345. If I were to run a 0.5mm gasket I might get away with it. The experiment is to try to use a 365SP piston, which is 1.5mm 0.060 taller than the stock 262XP piston. So I'm trying to figure out if there is a way to get close to 0.020 or even a little less using standard HVA or even AM gaskets without cutting a new squish band. In the past I would cut a custom gasket from 110 annealed precision copper shim stock but don't want to do that for a single experiment.

After all that krap, if any of you guys have any thoughts let me know.

IIRC there is a guy in Oz running .018 on a Dolmar 7900 for a couple of years now.  Mweba did .018 on a 562XP and it hit squish band while running.  He caught it before any major damage was done.  I try to stay as close to .020 myself on everything.  I've got a 44mm Stihl 026 (play toy)I may pull it down to .015 and see.
Shep

Your numbers look correct.  Consider that the connecting rod can grow a little when hot.  Older engine may have some wear on the crank pin bearing etc.  May want to stay around 22-25 thsdths.

I know of one 346 that is running at .013 and it runs great and has for several years. Not a toy either, it was a production firewood saw for at least two years.
My 346 is at around .020 and I wouldn't want to go any lower, I just don't feel like it gives any margin for safety. A couple thou. of carbon and bad things are starting to happen.


Mike