RING-LOCK 7G8121 - Caterpillar

Two Piece Articulated Piston
(1) Crown assembly.(2) Connecting rod. Install connecting rod and piston group with rod forging part number to the rear of the engine. The rear of the engine is the flywheel end. Thoroughly lubricate the piston group with clean engine oil just before inserting into block group.(3) Piston skirt. Thoroughly lubricate piston crown assembly and skirt 360 degrees in zone "A" with clean engine oil just before inserting into block group.Top And Intermediate Ring
Install piston ring with "UP" side toward top of piston (green color strip to right of ring gear).(4) Top Ring has the mark "UP-1". Clearance between ends of piston ring when installed in a cylinder with a bore size of 105 mm (4.134 in) ... 0.525 0.125 mm (0.0207 0.0049 in)Clearance between ends of piston ring when installed in a cylinder with a bore size of 110 mm (4.331 in) ... 0.525 0.125 mm (0.0207 0.0049 in)Increase in clearance between ends of piston ring for each 0.03 mm (0.001 in) increase in cylinder bore size ... 0.09 mm (0.004 in)Install intermediate ring with side marked "UP-2" toward top of piston (white color strip to right of ring end gap).(5) Intermediate Ring has the mark "UP-2". Clearance between ends of piston ring when installed in a cylinder with a bore size of 105 mm (4.134 in) ... 0.825 0.125 mm (0.033 0.0049 in)Clearance between ends of piston ring when installed in a cylinder with a bore size of 110 mm (4.331 in) ... 0.825 0.125 mm (0.033 0.0049 in)Increase in clearance between ends of piston ring for each 0.03 mm (0.001 in) increase in cylinder bore size ... 0.09 mm (0.004 in)Oil Control Ring
(6) Install Oil Control Ring with the gap in the spring 180 degrees away from the gap in the ring (light green colored portion of spring must be visible at the ring end gap).Width of groove in piston ring (new) ... 4.041 0.013 mm (0.1591 0.0005 in)Thickness of piston ring (new) ... 3.982 0.008 mm (0.1568 0.0003 in)Clearance between groove and piston ring (new) ... 0.038 0.080 mm (0.0015 0.0031 in)Clearance between ends of piston ring when installed in a cylinder with a bore size of 105 mm (4.134 in) ... 0.45 0.15 mm (0.018 0.006 in)Clearance between ends of piston ring when installed in a cylinder with a bore size of 110 mm (4.331 in) ... 0.45 0.15 mm (0.018 0.006 in)Increase in clearance between ends of piston ring for each 0.03 mm (0.001 in) increase in cylinder bore size ... 0.09 mm (0.004 in)After rings have been installed, rotate so end gaps are apart ... 120 degreesPiston Pin Bore
(7) Pin bore diameter in piston crown bearing ... 40.031 0.007 mm (1.5760 0.0003 in)Pin bore diameter in piston skirt ... 40.020 0.008 mm (1.5756 0.0003 in)Pin diameter ... 40.000 0.005 mm (1.5748 0.0002 in)Pin length: 8WL1-UP