patSS/00

iTrader: (6)

I don't know if this is advanced tech, anyway... As the engine heats up, does the piston out-of-the-hole height over the deck increase or decrease? I think with an aluminum block it would decrease, since AL has a larger expansion coefficient than iron / steel. So, the block deck height would expand more than the rods/crank/pistons. Is that right? Not really something you could measure very easily.

G Atsma

I think you are correct, with the coefficients of expansion what they are.

patSS/00

iTrader: (6)

Well if this means the quench area would increase, that would possibly allow more detonation at temp goes up. Of course that happens anyway, but maybe this is a factor, with aluminum block engines.