67077T 6 Mercury COVER

Illustration 1 g01391600Note: Refer to Guideline for Reusable Parts for information on the pistons, the piston pins, and the retaining rings.The 1U-6431 Piston Ring Groove Gauge Gp is used for measuring the ring grooves in keystone style pistons. Refer to the Special Instruction that is supplied with the piston ring groove gauge group.The 5P-3519 Piston Ring Groove Gauge Gp is available for checking the ring grooves with straight sides. Refer to the Guideline for Reusable Parts for instructions on the piston ring groove gauge group.Note: Lubricate the entire piston in zone (A) with clean engine oil prior to assembly into the cylinder block.Top Piston Ring (1)
Install the piston ring with the side marked "UP-1" toward the top of the piston. The purple colored stripe faces to the right of the piston ring end gap.When a new piston ring is installed in a cylinder liner with a bore of 145 mm (5.7 inch), the clearance between the ends of the piston ring is the following value: ... 0.40 0.10 mm (0.016 0.004 inch)Increase in clearance between the ends of the piston rings for each 0.030 mm (0.0012 inch) increase in the cylinder liner bore ... 0.08 mm (0.003 inch)Intermediate Piston Ring (2)
Install the piston ring with the side marked "UP-2" toward the top of the piston. The white-colored stripes face to the right of the piston ring end gap.When a new piston ring is installed in a cylinder liner with a bore of 145 mm (5.7 inch), the clearance between the ends of the piston ring is the following value: ... 0.825 0.125 mm (0.0325 0.005 inch)Increase in clearance between the ends of the piston ring for each 0.030 mm (0.0012 inch) increase in the cylinder liner bore ... 0.08 mm (0.003 inch)Oil Control Piston Ring (3)
The spring ends of the new piston ring should be a distance of 180 degrees from the ring end gap when the piston ring is assembled. The green colored stripe must be visible at the ring end gap.Width of groove in new piston for piston ring ... 3.020 0.010 mm (0.1189 0.0004 inch)Thickness of new piston ring ... 2.980 0.010 mm (0.1173 0.0004 inch)Clearance between groove and piston ring ... 0.05 mm (0.002 inch)When a new piston ring is installed in a cylinder liner with a bore of 145 mm (5.7 inch), the clearance between the ends of the piston ring is the following value. ... 0.55 0.15 mm (0.022 0.006 inch)Increase in clearance between the ends of the piston ring for each 0.030 mm (0.0012 inch) increase in the cylinder liner bore ... 0.08 mm (0.003 inch)Note: After all piston rings have been installed, rotate the piston rings so that the end gaps are 120 degrees from each other.Piston Pin Bore (4)
Note: Thoroughly lubricate the piston pin with clean engine oil before the piston is inserted into the piston and the rod assembly.Diameter of the bore in the bearing that is installed into the piston skirt for the piston pin ... 60.0925 0.0075 mm (2.36584 0.00030 inch)Diameter of the new piston pin ... 59.975 0.005 mm (2.3612 0.0002 inch)