Piston Inspection
PISTON INSPECTION1. Measure the piston outer diameter using the micrometer.
The measurement position is 10.0 mm (0.40 in) from the lower end of the piston and in the thrust direction.
- If it is not within the specification, replace the piston.
Standard piston outer diameter
87.465-87.495 mm (3.4435-3.4446 in)
2. Calculate the cylinder-to-piston clearance from the cylinder bore diameter and the piston outer diameter.
- If the clearance is at the maximum specification or more, replace the piston or cylinder block.
Clearance between piston and cylinder
Standard 0.025-0.045 mm (0.0010-0.0017 in)
Maximum 0.11 mm (0.0043 in)
3. Measure the piston-to-ring groove clearance along the perimeter using a feeler gauge.
- If the clearance is at the maximum specification or more, replace the piston or piston ring.
Clearance between piston ring and ring groove
Standard
Top: 0.005-0.08 mm (0.0020-0.0031 in)
Second: 0.03-0.07 mm (0.0012-0.0027in)
Oil: 0.02-0.06 mm (0.0008-0.0023 in)
Maximum
Top: 0.17 mm (0.0067 in)
Second, Oil: 0.15 mm (0.0059 in)
4. Measure the piston ring end gap using a feeler gauge.
- If it is at the maximum specification or more, replace the piston ring.
Piston ring end gap
Standard
Top: 0.14-0.24 mm (0.0056-0.0094 in)
Second: 0.34-0.44 mm (0.0134-0.0173 in)
Oil (rail): 0.15-0.40 mm (0.0060-0.0157 in)
Maximum
1.0 mm (0.0393 in)