Clean and Measure

CLEAN

- Tool Required - J 3936-03 Piston Ring Groove Cleaner, or equivalent.

Carbon from ring grooves using a piston ring groove cleaner. Clean carbon from remainder of piston head using a soft brush and solvent. Do not use a wire brush.

MEASURE

- Tool Required - J 26900-3 Outside Micrometer, or equivalent.





1. Piston diameter using an outside micrometer. Measure the diameter at a right angle to the piston pin centerline and 24.5 mm (0.965 inch) from the top of the piston head. Record measurement.
2. Piston oil clearance by subtracting the piston outside diameter from the cylinder bore inside diameter. Standard oil clearance is 0.085 to 0.105 mm (0.0033 to 0.0041 inch). If the piston oil clearance is greater than 0.13 mm (0.0051 inch) in any cylinder, replace all four pistons. If necessary, rebore all four cylinders or replace the cylinder block.
3. There are four sizes of pistons available. Three are standard size pistons and one is an oversize piston. Standard pistons are marked with a 1, 2 or a 3. The oversize pistons are 0.50 mm larger than the number 3 standard size pistons:
- 1-80.905 to 80.915 mm (3.1852 to 3.1856 inches).
- 2-80.915 to 80.925 mm (3.1856 to 3.1860 inches).
- 3-80.925 to 80.935 mm (3.1860 to 3.1864 inches).
- O/S-81.405 to 81.435 mm (3.2049 to 3.2061 inches).