you loose piston to head clearance when the engine heats up, not gain it.
???? Won't the tighter bore to skirt clearance at temperature reduce rocking and therefore increase clearance? What am I missing here?
Granted, piston rocking loads are greater than my thumb pressure, I've made no allowance for rod stretch at TDC exhaust nor crank deflection under load. And I'll lose .001 or so due to rod bearing clearance and maybe another .001 for main bearing clearance. Maybe all that adds up to more than .020 inches? I'm not so sure.
Please tell me what engines you've seen contact on, what pistons and bore clearance, and how may rpms you were running when it happened.
