New forged piston and rod beside a carbon-caked used piston and…

Two piston-and-connecting-rod assemblies laid side by side on paper for comparison: at left a clean forged piston with polished crown and machined valve reliefs, at right a used cast piston with a heavily carboned, discolored crown and scorched skirt. Both rods retain their caps and bearing bolts.

AI caption November 2005 · Photo 48 of 244