Piston: Testing and Inspection

1. Check the piston for distortion or cracks.

NOTE: If the cylinder is bored, an oversized piston must be used.





2. Measure the piston diameter at a point 18 mm (3/4 inch) from the bottom of the skirt.

NOTE: There are two standard-size pistons (No letter or A, and B). The letter is stamped on the top of the piston. Letters are also stamped on the block as cylinder bore sizes.

^ Piston Diameter:
- Standard (New):
^ No Letter or A: 86.980-86.990 mm (3.4244-3.4248 inch)
^ B: 86.970-86.980 mm (3.4240-3.4244 inch)
- Service Limit:
^ No Letter or A: 86.970 mm (3.4240 inch)
^ B: 86.960 mm (3.4236 inch)





3. Calculate the difference between cylinder bore diameter and piston diameter.

^ Piston-to-Cylinder Clearance:
- Standard (New): 0.020-0.040 mm (0.0008-0.0016 inch)
- Service Limit: 0.08 mm (0.003 inch)

NOTE: If the clearance is near or exceeds the service limit, inspect the piston and cylinder block for excessive wear.

^ Oversize Piston Diameter:
- 0.25: 87.230-87.240 mm (3.4342-3.4346 inch)
- 0.50: 87.480-87.490 mm (3.4441-3.4445 inch)