SCREW 7U4892 - Caterpillar

Make reference to Guideline For Reusable Parts; Pistons, SEBF8049; Cylinder Liners, SEBF8068; and Piston Pins And Retaining Rings, SEBF8051. For installation, number on tab groove side of connecting rod is to be positioned toward opposite side of engine from camshaft.Top And Intermediate Ring
The 8T3150 Keystone Piston Ring Groove Indicator is necessary for measuring ring grooves in keystone style pistons. For correct use of the indicator group, see the instruction card that is with the indicator group.Install piston rings with "UP" side toward top of piston.(1) Top Ring has the mark "UP-1."(2) Intermediate ring has the mark "UP-2".Clearance between ends of piston ring when installed in a cylinder liner with a bore size of 137.16 mm (5.400 in):Top ring ... 0.724 0.190 mm (.0285 .0075 in)Intermediate ring ... 1.080 0.190 mm (.0425 .0075 in)Increase in clearance between ends of piston rings for each 0.03 mm (.001 in) increase in cylinder liner bore size ... 0.08 mm (.003 in)Oil Control Ring
(3) Install oil control ring with the gap in the spring 180 degrees away from the gap in the ring. White portion of spring must be visible at the ring end gap.Width of groove in piston for piston ring (new) ... 3.21 .01 mm (.126 .0004 in)Thickness of piston ring (new) ... 3.137 0.013 mm (.1235 .0005 in)Clearance between groove and piston ring (new) ... 0.051 0.025 mm (.0020 .0010 in)Maximum permissible clearance (worn) ... 0.15 mm (.006 in)Clearance between ends of piston ring when installed in a cylinder liner with a bore size of 137.16 mm (5.400 in) ... 0.570 0.190 mm (.0225 .0075 in)Increase in clearance between ends of piston ring for each 0.03 mm (.001 in) increase in cylinder liner bore size ... 0.08 mm (.0003 in)Piston Pin Bore
(4) Bore in piston for pin. Vertical ... 55.021 .004 mm (2.1662 .0002 in)Clearance between pin and bore in piston ... 0.010 to 0.028 mm (.0004 to .0011 in)Permissible clearance (worn) ... 0.05 mm (.002 in)Pin diameter ... 55.00 0.005 mm (2.165 .0002 in)