Ovality and other guarded racing piston matters

Below their ring lands, pistons are neither round nor do they have parallel sides, instead they have a larger diameter towards the bottom, usually between the base of the piston and the piston pin hole, and become progressively smaller toward the top of the piston. This design logic allows for greater expansion of the piston crown because it’s the region closest to the heat source.

Read the full story courtesy of Drag Racer Magazine here.