C4.4 Engines for Caterpillar Built Machines Caterpillar

Illustration 1	g01155119
Typical example

(1) Top compression ring

The shape of the top compression ring ... tapered

Ring gap ... 0.30 to 0.45 mm (0.0118 to 0.0177 inch)

Note: When you install a new top compression ring, make sure that the word "TOP" is facing the top of the piston. New top piston rings have a yellow identification mark which must be on the left of the ring end gap when the top piston ring is installed on an upright piston.

(2) Intermediate compression ring

The shape of the intermediate compression ring ... Internal bevel in the bottom edge with a tapered face

Width of intermediate compression ring ... 2.47 to 2.495 mm (0.0972 to 0.0982 inch)

The clearance between a new intermediate compression ring and the piston groove in a new piston ... 0.07 to 0.11 mm (0.00276 to 0.00433 inch)

Ring gap ... 0.65 to 0.85 mm (0.0256 to 0.0335 inch)

Note: When you install a new intermediate compression ring, make sure that the word "TOP" is facing the top of the piston. New intermediate rings have a blue identification mark which must be on the left of the ring end gap when the top piston ring is installed on an upright piston.

(3) The oil control ring

Width of oil control ring ... 2.97 to 2.99 mm (0.1169 to 0.1177 inch)

The clearance between a new oil control ring and the groove in a new piston ... 0.03 to 0.07 mm (0.0011 to 0.0027 inch)

Ring gap ... 0.25 to 0.45 mm (0.00984 to 0.01772 inch)

Note: The oil control ring is a two-piece ring that is spring loaded. A pin is used in order to hold both ends of the spring of the oil control ring in position. The ends of the spring of the oil control ring must be installed opposite the end gap of the oil control ring.

Note: Ensure that the ring end gaps of the piston rings are spaced 120 degrees from each other.

Piston

Note: An arrow which is marked on the piston crown must be toward the front of the engine.

Piston height above cylinder block ... 0.40 to 0.54 mm (0.0157 to 0.0213 inch)

Width of top groove in the piston ... Tapered

Width of second groove in new piston ... 2.56 to 2.58 mm (0.1008 to 0.1016 inch)

Width of third groove in new piston ... 3.02 to 3.04 mm (0.1189 to 0.1197 inch)

Piston pin

Diameter of a new piston pin ... 39.694 to 39.700 mm (1.5628 to 1.5630 inch)