Piston

Piston

Notice: Replacing a piston also requires replacing piston rings.





1. Check circumference of piston for damage, scoring, or unusual wear patterns. Replace piston as needed.
2. Check outside diameter of each piston at a 90° right angle to piston pin, 0.650 inch (16.5 mm) below oil ring land's lower edge.

Piston diameter:
Standard: 3.1872 - 3.1879 inch (80.954 - 80.9720 mm)
Bore + 0.010 inch (0.25 mm): 3.197 - 3.1977 inch (81.204 - 81.222 mm)
Bore + 0.020 inch (0.50 mm): 3.2069 - 3.2076 inch (81.454 - 81.472 mm)

Notice: If piston is collapsed or bell mouthed, replace piston.





3. Check piston-to-cylinder wall clearance by subtracting piston diameter from the largest cylinder wall diameter, at each cylinder.
Clearance: 0.0015 - 0.0021 inch (0.039 - 0.053 mm)
Maximum: 0.006 inch (0.15 mm)





4. If clearance exceeds maximum, replace piston or rebore cylinders and fit oversized pistons to all cylinders.