SEAL-O-RING 8J8725 - Caterpillar

Illustration 1 g00935410
For more information, refer to the following publications: Guidelines for Reusable Parts, SEBF8049, "Pistons", Guidelines for Reusable Parts, SEBF8051, "Piston Pins and Retaining Rings" and Guidelines for Reusable Parts, SEBF8068, "Cylinder Liners".Note: If the piston and rod group is replaced, make sure that the cylinder number is etched on the connecting rod and on the cap. Refer to Specifications, "Connecting Rod". (1) Top ringInstall the top ring with the "UP-1" mark toward the top of the piston. Width of piston ring groove ... 3.864 0.010 mm (0.1521 0.0004 inch) Thickness of new piston ring ... 3.790 0.019 mm (0.1492 0.0007 inch) Clearance between groove and new piston ring ... 0.045 to 0.103 (0.0018 to 0.0041 inch) Gap between the ends of a new piston ring that is installed in a cylinder liner bore of 137.16 mm (5.400 inch) ... 0.72 0.19 mm (0.028 0.008 inch) (2) Intermediate ringInstall the intermediate ring with the "UP-2" mark toward the top of the piston. Width of piston ring groove ... 3.060 0.010 mm (0.1205 0.0004 inch) Thickness of new piston ring ... 2.985 0.015 mm (0.1175 0.0006 inch) Clearance between groove and new piston ring ... 0.05 to 0.10 mm (0.0039 to 0.002 inch) Gap between the ends of a new piston ring that is installed in a cylinder liner bore of 137.16 mm (5.400 inch) ... 0.575 0.175 mm (0.0226 0.0069 inch) (3) Oil ring Width of groove in piston for new piston ring ... 4.030 0.010 mm (0.1587 0.0004 inch) Thickness of new piston ring ... 3.975 0.015 mm (0.1565 0.0006 inch) Clearance between groove and new piston ring ... 0.030 to 0.080 mm (0.0012 to 0.0031 inch) Gap between the ends of a new piston ring that is installed in a cylinder liner bore of 137.16 mm (5.400 inch) ... 0.575 0.175 mm (0.0226 0.0069 inch) Difference in orientation of the spring's gap and the ring's gap ... 180 degreesDifference in orientations of the three installed rings' gaps ... 120 degrees (4) Bore Bore diameter ... 51.10 to 51.30 mm (2.0118 to 2.0197 inch) (5) Piston pin Pin diameter ... 49.800 0.500 mm (1.9606 0.0197 inch) Clearance between pin and bore ... 0.80 to 2.00 mm (0.032 to 0.079 inch)Immediately before the piston pin is installed into the piston and into the connecting rod, thoroughly lubricate the pin with clean engine oil. (6) Pin retainerWhen the pin retainers are installed, verify that the retainers are securely seated in the grooves.Immediately before the piston is installed into the cylinder liner, thoroughly lubricate the piston's body with clean engine oil.