105921-0920 ZEXEL 9 420 610 136 BOSCH GOVERNOR 9420610136 1059210920 19200l9205

Make reference to Guideline For Reusable Parts; Pistons, Form No. SEBF8049; Cylinder Liners, Form No. SEBF8068; and Piston Pins And Retaining Rings, Form No. 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 Gauge is necessary for measuring ring groove in keystone style pistons. For correct use of the gauge group, see the 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 0.191 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° 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) ... 3.210 0.010 mm (.1264 .0004 in)Thickness of piston ring (new) ... 3.137 0.013 mm (.1235 .0005 in)Clearance between groove and piston ring (new) ... 0.073 0.023 mm (.0029 .0009 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) Bore in piston for pin. 1991 Model with elliptical pin bore (310 - 425 hp) Vertical ... 50.814 0.004 mm (2.0005 .0001 in)Horizontal ... actual vertical diameter plus 0.032 to 0.048 mm (.0012 to .0019 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 ... 50.795 0.005 mm (1.9998 .0002 in) Low Crevice Volume and Gallery Pistons Bore in piston for pin ... 50.814 0.004 mm (2.0005 .0001 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 ... 50.795 0.005 mm (1.9998 .0002 in)All Other Pistons Bore in piston for pin ... 50.815 0.008 mm (2.0006 .0003 in)Clearance between pin and bore in piston ... 0.007 to 0.032 mm (.0003 to .0013 in)Permissible clearance (worn) ... 0.05 mm (.002 in)Pin diameter ... 50.795 0.005 mm (1.9998 .0002 in)