Andy;

    Yes the piston will expand, how much of the expansion it will retain I don't know. I use the oven trick to remove stuck liners. I heat the oven to 350* and leave case and liner in for about 20 minutes. When you take it out just turn the crank a little and the liner lifts out of the case, just pull it out. I have done this hundreds of times with no ill effects to the oven. FWIW

"Billy G"   

EDIT------I am not an expert, but it works for me.

Thanks guys I will try to get in touch with Scott.  Hopefully he has an email listed here.
Andy

I read sometime back about a technique for expanding the piston of an older motor.  Something about putting the piston in the oven at some temperature for some amount of time with the end result of a slightly larger piston.  First off is this true, and if it is what are the parameters for doing this.  What temp, for how long and what is the cool down process.

I am currently cleaning up a couple of McCoy .35 read heads and if the compression is low I might want to do this if it really does work.  While looking for an engine I have misplaced I stumbled across these McCoys, I have no idea how long I have had them.  One has a centered glow plug and the other is off center, what is the explanation for this, and finally does anybody make replacement parts such as piston and cylinders for these old engines?
Andy

I Andrew

The baking the piston in the oven almost NEVER works with motors that have been run and worn out. I have tried it on dozens of pistons with dismal results. The reason it does not work is that the piston has already been heat cycled over and over again, many times hotter than the oven gets it.  If you have a  piston that has a lot of growth in it and has not been run mcuh or any you could get a nice fit out of it.
Baking the carbon build up hard on the side is no good either even though it may feel like the piston is tighter

The best way to refurb and old piston sleeve is to make sure the pin boss and body of the piston is good, the have the sleeve chromed and  refit teh piston\sleeve up.
Don't let this stop you from trying but please let us know the results  after you have the motor back together and have  several  flights on it..
Regards
Randy