Piston Inspection
PISTON INSPECTIONCAUTION: If the piston is replaced, replace the piston, piston pin, and the snap ring as a single component.
1. Measure the piston outer diameter using the micrometer. The measurement position is 8.0 mm {0.31 in} from the lower end of the piston (area with no coating on the piston skirt) and in the thrust direction.
- If it is not within the specification, replace the piston.
Standard piston outer diameter 83.465-83.495 mm {3.2861-3.2872 in}
2. Measure the cylinder bore diameter. (See CYLINDER BLOCK INSPECTION.)
3. Calculate the cylinder-to-piston clearance from the cylinder bore diameter and the piston outer diameter.
- If the clearance exceeds the maximum specification, replace the piston or cylinder block.
Standard clearance between piston and cylinder 0.025-0.045 mm {0.0010-0.0017 in}
Maximum clearance between piston and cylinder 0.063 mm {0.0025 in}
4. Measure the piston-to-ring groove clearance along the perimeter using a feeler gauge. For the O-ring, measure the clearance with the O-ring assembled to the piston.
- If the clearance exceeds the maximum specification, replace the piston or piston ring.
Standard clearance between piston ring and ring groove
Top: 0.04-0.08 mm {0.002-0.003 in}
Second: 0.03-0.07 mm {0.0012-0.0027 in}
Oil: 0.04-0.12 mm {0.002-0.004 in}
Maximum clearance between piston ring and ring groove
Top: 0.12 mm {0.0047 in}
Second: 0.10 mm {0.0039 in}
Oil: 0.17 mm {0.0067 in}