Grand Prix V6-191 3.1L VIN M SFI (1998)
Piston: Description and Operation
The pistons are cast aluminum using two low tension compression rings and one oil control ring. The piston pin is offset 0.8 mm (0.031 inch) towards
the major thrust side. This allows a gradual change in thrust pressure against the cylinder wall as the piston travels its path. Pins are chromium steel and
have a floating fit in the pistons. They are retained in the connecting rods by a press fit.