 | |
| Illustration 1 | g00922883 |
(1) Piston crown (2) Piston ring (3) Piston skirt (4) Piston pin and pin retainer (5) Connecting rod (6) Connecting rod bolts (7) Connecting rod cap | |
The piston is a two-piece, articulated design. The piston consists of a forged, steel crown and a cast, aluminum skirt. The two pieces of the piston assembly are connected to the piston pin. The two pieces of the piston assembly pivot about the piston pin. The steel crown carries all three piston rings. Oil from the piston cooling jets flows through a chamber which is located behind the piston rings. This cools the piston and the piston rings in order to maintain proper performance and service life of the piston and of the piston ring.
The pistons have three rings which include two compression rings and one oil ring. All the rings are located above the piston pin bore. The oil ring is a standard ring. Oil returns to the crankcase through holes in the oil ring groove. The top two rings are the Keystone rings. The rings have a side that is tapered inward. The piston ring groove must have a taper with an angle that is similar to taper of the piston ring. This allows the piston to be strengthened in the lands between the piston grooves. During the operation of the engine, movement of the piston breaks up the formation of carbon between the ring and the piston. The design will help prevent a sticking ring.
The connecting rod has a taper on the pin bore end. This taper gives the connecting rod and the piston more strength in the areas with the most load. Four bolts, which are set at a small angle, hold the connecting rod cap to the connecting rod. This design keeps the connecting rod width to a minimum, so that a larger connecting rod bearing can be used and the connecting rod can still be removed through the liner.