The head is dished to provide part of the combustion space. Deep, narrow-sectioned ring grooves provide for a large ring bearing surface in the piston with minimum friction between rings and cylinder walls. There are 4 compression rings and 2 oil control rings per piston, all above the piston pin. The piston-pins are carburized, hardened and ground to extremely low limits. They are of full-floating hollow type, free to turn in both piston and connecting rod.
Snap rings hold the pin in position.
The lower bearing is babbitt-lined and is of the precision type. The bearings are finished to an exact size and can be installed without shimming, filing or hand-fitting. The upper bearing is a heavy bronze precision-bored bushing which fits into the small end of the rod. The crankshaft is a high-carbon steel drop forging. Drilled passages are provided for pressure lubrication to the crankpin bearings and other parts.