66897 Mercury BOLT, UPPER MOUNT TO SWIVEL PIN (7/16 X 5 1/4")

Illustration 1 g00845975
(1) The chamber that is on the top of the piston must face the right side of the engine. (2) The Shibaura name that is forged on the inside of the piston must align with the marks that are on the connecting rod.Piston Rings
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The gaps in the piston rings must be spread apart by 90 degrees. (1) Top piston ring Shape of top ring (A) ... Barrel faceNote: Install the scribe mark on the piston ring toward the top of the piston. (2) Intermediate ring Shape of intermediate ring (B) ... TaperNote: Install the scribe mark on the ring toward the top of the piston. (3) Oil control ringNote: Install the scribe mark on the ring toward the top of the piston.The oil control ring has two components. The two components of the oil control ring are installed in the following order:
Spring (D)
Oil control ring (C) Note: Use a piston to insert the piston ring square with respect to the cylinder bore. The top surface of the piston ring should be equally distant from the face of the cylinder block at all points before the piston ring end gap is measured. (4) Piston
Illustration 3 g00845991
(5) Feeler gauge (6) Piston ring Gap for No. 1 piston ring on naturally aspirated engines ... 0.20 to 0.35 mm (0.008 to 0.014 inch) Gap for No. 1 piston ring on turbocharged engines ... 0.25 to 0.40 mm (0.00984 to 0.01575 inch) Service limit for No. 1 piston ring ... 1.0 mm (0.04 inch) Gap for No. 2 piston ring on naturally aspirated engines ... 0.20 to 0.40 mm (0.008 to 0.016 inch) Gap for No. 2 piston ring on turbocharged engines ... 0.50 to 0.70 mm (0.01969 to 0.02756 inch) Service limit for No. 2 piston ring ... 1.0 mm (0.04 inch) Gap for oil control ring ... 0.20 to 0.50 mm (0.00787 to 0.01969 inch) Service limit for oil control ring ... 1.0 mm (0.04 inch)Measure the clearance between the piston ring groove and the piston ring. If the clearance exceeds the service limit, then replace the pistons and the rings. Clearance for the No. 1 piston ring ... 0.07 to 0.11 mm (0.003 to 0.004 inch) Service limit for No. 1 piston ring ... 0.25 mm (0.010 inch) Clearance for No. 2 piston ring ... 0.04 to 0.08 mm (0.002 to 0.003 inch) Service limit for No. 2 piston ring ... 0.25 mm (0.010 inch) Clearance for the oil control ring ... 0.02 to 0.06 mm (0.001 to 0.002 inch) Service limit for the oil control ring ... 0.15 mm (0.006 inch)Pistons
Diameter of piston Standard piston ... 83.948 to 83.963 mm (3.3050 to 3.3056 inch) Service limit ... 83.7 mm (3.30 inch) Diameter of piston skirt ... 83.948 to 83.963 mm (3.3050 to 3.3056 inch)Clearance of the piston to the cylinder wall Standard clearance ... 0.038 to 0.072 mm (0.0015 to 0.0028 inch) Service limit ... 0.25 mm (0.010 inch)Piston pin Outside diameter ... 27.996 to 28.000 mm (1.1022 to 1.1024 inch) Service limit ... 27.98 mm (1.102 inch)Clearance between the hole for the piston pin and the piston pin Standard clearance ... -0.001 to +0.007 mm (-0.0004 to +0.0003 inch) Service limit ... 0.02 mm (0.001 inch)