RING 2M3964 - Caterpillar

Make reference to Guideline For Reusable Parts, Pistons, SEBF8049, and Guideline For Reusable Parts, Piston Pins And Retaining Rings, SEBF8051.Top And Intermediate Ring
The 1U6431 Keystone Piston Ring Groove Gauge is necessary for measuring ring grooves in keystone style pistons. For correct use of the gauge group, refer to SEES5678 Instruction Card that is with the gauge 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 ... 0.673 0.190 mm (.0265 .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.The 5P3519 Piston Ring Groove Gauge is available for checking ring grooves with straight sides. For instructions on the use of the gauge, refer to Guideline For Reusable Parts, Pistons, SEBF8049.Width of groove in piston for piston ring (new) ... 3.188 0.013 mm (.1255 .0005 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) ... 0.572 0.191 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 (.003 in)Piston Pin Bore
(4) This piston has an elliptical (not round) pin bore. Measure the pin bore only in the vertical direction ... 50.86 + 0.15, - 0.00 mm (2.002 + .006, - .000 in)(5) Pin diameter ... 50.795 0.005 mm (1.9998 .0002 in)