crankshaft

predetonation- that is a good point. i did not think of that because the fuel is detonated by the compression, but that would be possible at high temperatures. still, i think that is unlikely within any reasonable temperature. I have never heard of anyone having problems with detonation before top dead center with one of these engines. i think before you get the engine hot enough to cause predetonation or to soften the piston enough that damage could be done to it you would do damage as a result of being too lean. the metal will expand as it gets hot and its properties will change, as will its size to some degree, but this does not occurr continuously. the only significant change in the metal occurrs during the first few heat cycles, thus, break in. the other thing is, the sleeve is made out of aluminum, the same stuff as the piston, rod, and block, so the expansion will be the same on all of them, and at that, the piston gets hotter than anything in there, so it will see the most expansion. these engines are made with a lot of clearance between the piston and sleeve to alllow for expansion.