Piston assembly and method of manufacture

A method of manufacturing a piston assembly, comprising the steps of:

• forming a first side wall having a first angle outwardly converging from an inner peripheral wall to an outer peripheral wall of a piston ring;
• forming a second side wall having a second angle outwardly converging from the inner peripheral wall to the outer peripheral wall of the piston ring;
• forming a groove in a piston, said groove including a first wall having a third angle outwardly converging from a base of said groove to an outer surface of said piston and said groove including a second wall having a fourth angle outwardly converging from said base to said outer surface;
• inserting said piston ring into said groove of said piston;
• whereby said first angle is approximately equal to said third angle and said second angle is approximately equal to said fourth angle;
• and
• whereby said first angle is different than said second angle said first angle is approximately twelve degrees and said second angle is approximately three degrees.