Inspection

INSPECTION

PISTON

Replace the piston if scratches or seizure is evident on its surfaces (especially the thrust surface). Replace the piston if it is cracked.

PISTON PIN

1. Insert the piston pin into the piston pin hole with a thumb. You should feel a slight resistance. Replace the piston pin if it can be easily inserted or there is excessive play.

2. The piston and piston pin must be replaced as an assembly.

PISTON RING

1. Check the piston ring for damage, excessive wear, and breakage. Replace if defects are evident. If the piston has been replaced with a new one, the piston rings must also be replaced with new ones.





2. Check for clearance between the piston ring and ring groove. If the limit is exceeded, replace the ring or piston, or both.
Standard value:

Number 1: 0.03 - 0.07 mm (0.0012 - 0.0027 inch)
Number 2: 0.02 - 0.06 mm (0.0008 - 0.0023 inch)
Limit: 0.1 mm (0.003 inch)






3. Insert the piston ring into the cylinder bore. Force the ring down with a piston, the piston crown being in contact with the ring, to correctly position it at right angles to the cylinder wall. Then, measure the end gap with a feeler gauge.
If the ring gap is excessive, replace the piston ring.
Standard value:

Number 1: 0.25 - 0.40 mm (0.010 - 0.016 inch)
Number 2: 0.35 - 0.50 mm (0.014 - 0.020 inch)
Oil: 0.10 - 0.35 mm (0.004 - 0.014 inch)
Limit:

Number 1, Number 2: 0.8 mm (0.03 inch)
Oil: 1.0 mm (0.03 inch)


CRANKSHAFT PIN OIL CLEARANCE [PLASTIGAGE METHOD]





The crankshaft oil clearance can be measured easily by using plastigage, as follows:
1. Remove oil from the crankshaft pin and the bearing inner surface.
2. Cut plastigage to the same length as the width of the bearing and place it on the pin in parallel with its axis.
3. Install the connecting rod cap carefully and tighten the nuts to the specified torque.
4. Carefully remove the connecting rod cap.
5. Measure the width of the smashed plastigage at its widest section by using a scale printed on the plastigage bag.
Standard value: 0.020 - 0.044 mm (0.0008 - 0.0017 inch)
Limit: 0.1 mm (0.003 inch)