PURPOSE: To prevent combination due to microwelding between a piston ring and an insert by using a piston and an insert setting aluminum as base metal.

CONSTITUTION: An annular composite insert 10 is cast, which includes distinct particles 22 such as cast iron dispersed throughout the base metallic alloy 20 of aluminum. The insert is then arranged in a piston mold, and a piston 34 is cast, so that the insert maintains a radially outer face generally flush with a radially outer surface of a piston head 36 of the piston. The base metal of the piston is preferably the same as that of the insert so that the insert shares the same thermal expansion coefficient as the piston. The insert is machined to form grooves 42 adapted to receive piston rings. The particles 22 of the insert are exposed to provide superior wear resistance.