
A piston assembly (10) of the type for reciprocating in an internal combustion engine. The assembly (10) includes an integral aluminum head (12) and skirt (14). The skirt (14) has an outer surface for engaging a cylinder wall which includes a plurality of pointed ridges (24). The pointed ridges (24) extend annularly about the skirt (14) and are each separated by a valley (26). The ridges (24) and valleys (26) are coated with a fluorocarbon polymer. The piston therefore has an improved wear surfa...











