90042 Mercruiser SCREW, (.437-14 x 1.500)

Illustration 1 g01084998
Typical example
This piston has a Keystone top ring. This piston also has Keystone intermediate rings. The 204-8041 Piston Ring Groove Gauge Gp is necessary for measuring the ring grooves in the Keystone pistons. For correct use of the gauge group, refer to the instruction card that is with the gauge group.Note: Prior to the installation of the rings, the ring grooves must be completely lubricated with clean engine oil. After assembly, the mating surfaces of the rings to the cylinder liner must be completely lubricated with clean engine oil. (1) Top piston ring Install the piston ring with the "Up-1" side toward the top of the piston. When the piston ring is installed in a cylinder liner with a bore size of 170 mm (6.7 inch), the clearance between the ends of the piston ring is the following value. ... 0.625 0.125 mm (0.0246 0.0050 inch)The increase in the clearance between the ends of the piston ring for each 0.03 mm (0.001 inch) increase in the cylinder liner bore size is the following value. ... 0.08 mm (0.003 inch) (2) Intermediate piston ring Install the piston ring with the "Up-2" side toward the top of the piston. When the piston ring is installed in a cylinder liner with a bore size of 170 mm (6.7 inch), the clearance between the ends of the piston ring is the following value. ... 1.00 0.15 mm (0.039 0.006 inch)The increase in the clearance between the ends of the piston ring for each 0.03 mm (0.001 inch) increase in the cylinder liner bore size is the following value. ... 0.08 mm (0.003 inch) (3) Oil piston ring Width of groove in piston for the new oil piston ring ... 4.055 0.015 mm (0.1596 0.0006 inch)Maximum thickness of new oil piston ring ... 3.980 0.010 mm (0.1570 0.0004 inch)Clearance between groove and new oil piston ring ... 0.050 to 0.100 mm (0.0020 to 0.0039 inch)When the piston ring is installed in a cylinder liner with a bore size of 170 mm (6.7 inch), the clearance between the ends of the piston ring is the following value. ... 0.65 0.15 mm (0.026 0.006 inch)The increase in the clearance between the ends of the piston ring for each 0.03 mm (0.001 inch) increase in the cylinder liner bore size is the following value. ... 0.08 mm (0.003 inch)Note: Install the oil piston ring so that the gap in the spring is 180 degrees away from the gap in the piston ring. The white portion of the spring must be visible at the ring end gap.Note: After all of the piston rings have been installed, rotate the piston rings so that the end gaps are separated by 120 degrees. The ring gap for the oil piston ring must be aligned in the plane of the pin bore. (4) Piston pin bore Note: Prior to assembly of the piston pin, the piston pin, the piston pin bore, the connecting rod eye, and the connecting rod pin bearing must be completely lubricated with clean engine oil.Crown as Measure the pin bore in the bushings in two places for each bushing in a vertical direction. Bore in bushing ... 70.0525 0.0075 mm (2.75796 0.00029 inch)Piston skirt Measure the pin bore in a vertical direction. Bore ... 69.988 0.005 mm (2.7554 0.0002 inch) (5) Piston pin Measure the pin diameter on each end in a vertical and horizontal direction. Outside diameter ... 69.962 0.005 mm (2.7544 0.0002 inch)Inside diameter ... 33.0 0.5 mm (1.30 0.02 inch)Length ... 137.55 0.15 mm (5.415 0.006 inch) (6) Pin retainer ... Assemble the pin retainer with the opening above line A-A.