12755 Mercury SPRING, REVERSE HOOK -STARBOARD

(1) Body assembly. Install piston with "FRONT" toward front of engine. Assemble so the markings "FRONT" on the piston body assembly and the forging part number on the connecting rod assembly point in opposite directions. 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.(2) Connecting rod.Top And Intermediate Ring
Install piston ring with "UP" side toward top of piston.(3) Top Ring has the mark "UP-1". Clearance between ends of piston ring when installed in a cylinder with a bore size of 105.025 mm (4.1348 in) ... 0.525 0.125 mm (.021 .005 in)Increase in clearance between ends of piston ring for each 0.03 mm (.001 in) increase in cylinder bore size ... 0.09 mm (.004 in)(4) Intermediate Ring has the mark "UP-2". Clearance between ends of piston ring when installed in a cylinder with a bore size of 105.025 mm (4.1348 in) ... 0.828 0.125 mm (.033 .005 in)Increase in clearance between ends of piston ring for each 0.03 mm (.001 in) increase in cylinder bore size ... 0.09 mm (.004 in)Oil Control Ring
(5) 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) ... 4.041 0.013 mm (.1591 .0005 in)Clearance between groove and piston ring (new) ... 0.038 to 0.080 mm (.0015 to .0031 in)Clearance between ends of piston ring when installed in a cylinder with a bore size of 105.025 mm (4.1348 in) ... 0.45 0.15 mm (.018 .006 in)Increase in clearance between ends of piston ring for each 0.03 mm (.001 in) increase in cylinder bore size ... 0.09 mm (.004 in)After rings have been installed, rotate so end gaps are apart ... 120°Piston Pin Bore
(6) Pin bore diameter ... 40.020 0.008 mm (1.5756 .0003 in) Pin diameter ... 40.000 0.005 mm (1.5748 .0002 in)Thoroughly lubricate pin with clean engine oil before assembling to piston group and connecting rod.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.Top And Intermediate Ring
Install piston ring with "UP" side toward top of piston.(4) Top Ring has the mark "UP-1". Clearance between ends of piston ring when installed in a cylinder with a bore size of 105.025 mm (4.1348 in) ... 0.525 0.125 mm (.021 .005 in)Increase in clearance between ends of piston ring for each 0.03 mm (.001 in) increase in cylinder bore size ... 0.09 mm (.004 in)(5) Intermediate Ring has the mark "UP-2". Clearance between ends of piston ring when installed in a cylinder with a bore size of 105.025 mm (4.1348 in) ... 0.828 0.125 mm (.0033 .005 in)Increase in clearance between ends of piston ring for each 0.03 mm (.001 in) increase in cylinder bore size ... 0.09 mm (.004 in)Oil Control Ring
(6) 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) ... 4.041 0.013 mm (.1591 .0005 in)Thickness of piston ring (new) ... 3.982 0.008 mm (.1568 .0003 in)Clearance between groove and piston ring (new) ... 0.038 to 0.080 mm (.0015 to .0031 in)Clearance between ends of piston ring when installed in a cylinder with a bore size of 105.025 mm (4.1348 in) ... 0.45 0.15 mm (.018 .006 in)Increase in clearance between ends of piston ring for each 0.03 mm (.001 in) increase in cylinder bore size ... 0.09 mm (.004 in)After rings have been installed, rotate so end gaps are apart ... 120°Piston Pin Bore
(7) Pin bore diameter in piston crown bearing ... 40.031 0.007 mm (1.5760 .0003 in) Pin bore diameter in piston skirt ... 40.020 0.008 mm (1.5756 .0003 in)Pin diameter ... 40.000 0.005 mm (1.5748 .0002 in)Thoroughly lubricate pin with clean engine oil before assembling to piston group and connecting rod.