Piston, Engine

Pistons and piston rings





Checking piston diameter
^ Measure pistons approximately 10 mm (3/8 inch) from bottom edge at right angle (90°) to piston pin.
Deviation from nominal size: 0.04 mm (0.0016 inch).

Piston and cylinder bore dimensions
Basic dimension 82.48 mm (3.247 inch)
1st oversize 82.74 mm (3.257 inch)

Checking piston ring side clearance
Clearance when new 0.02 - 0.08 mm (0.0008 - 0.0031 inch)
Wear limit 0.10 mm (0.004 inch)

Piston Ring
End Gap
1)Compression 0.35-0.50 mm (0.014-0.020 in.)
2)Compression 0.50-0.70 mm (0.020-0.028 in.)
3)Oil scraper 0.25-0.50 mm (0.010-0.020 in.)
Wear limit
1)Compression (1.0 mm (0.039 in.)
2)Compression (1.4 mm (0.043 in.)
3)Oil scraper 0.8 mm (0.031 in.)





Piston and cylinder bore dimensions
Engine codes AHA, ATQ

Note: Replacement pistons are only available in the basic dimension.

CAUTION: DO NOT measure cylinder bore dimensions while the cylinder block is mounted on the engine stand. The cylinder block is stressed and deformed by its own weight under these conditions and the measurements will not be accurate.