Piston: Testing and Inspection

1. Using a gasket scraper, remove the carbon from the piston top.






2. Using a groove cleaning tool or broken ring, clean the piston ring grooves.






3. Using solvent and a brush, thoroughly clean the piston.

NOTE: Do not use a wire brush.





4. Inspect piston oil clearance. Using a micrometer, measure the piston diameter at right angles to the piston pin center line, 26 mm (1.02 inch) from the piston head.
Piston diameter:
Pistons with mark "1": 87.410-87.420 mm (3.4413-3.4417 inch)
Pistons with mark "2": 87.420-86.430 mm (3.4417-3.4421 inch)
Pistons with mark "3": 87.430-87.440 mm (3.4421-3.4425 inch)

NOTE:
- There are three sizes of the standard piston diameter, marked "1", "2" and "3" accordingly. The mark is stamped on the piston top.
- The shape of the piston varies for the RH and LH banks. The RH piston is marked with "R", the LH piston with "L"
- Ensure piston and bore have the same number mark.






5. Using a suitable cylinder gauge, measure the cylinder bore diameter at positions A, B and C in the thrust direction.





6. Subtract the piston diameter measurement from the cylinder bore diameter measurement to determine oil clearance.
Standard oil clearance: 0.080-0.100 mm (0.0031-0.0039 inch).
Maximum oil clearance: 0.120 mm (0.0047 inch).
If the oil clearance is greater than maximum, replace all the eight pistons. If necessary, replace the cylinder block.