The BEST technique for finding TDC is to stop the piston short of full up stroke with a reference point on the balancer or with a degree wheel and pointer, using some kind of stop that is rigid and stays put, and mark that spot. Rotate the reciprocating assembly in the opposite direction until it reaches the same point and mark that spot on your wheel or balancer. Find the point that is exactly halfway between the two and that will be the Top Dead Center point of your rotating assembly.
