Pistons and Connecting Rod

Fig. 10

DESCRIPTION
The pistons are elliptically turned so that the diameter at the pin boss is less than its diameter across the thrust face. This allows for expansion under normal operating conditions. Under operating temperatures, expansion forces the pin bosses away from each other, causing the piston to assume a more nearly round shape.
All pistons are machined to the same weight, regardless of size, to maintain piston balance.
The piston pin rotates in the piston only and is retained by the press interference fit of the piston pin in the connecting rod.
The pistons have a unique dry-film lubricant coating baked onto the skirts to reduce friction. The lubricant is particularly effective during engine break-in, but with time, the material becomes embedded into cylinder bore walls and continues to reduce friction.
The pistons are LH and RH bank specific.