CYLINDER HEAD, CYLINDER AND PISTON 6-23
PISTON RING-TO-GROOVE CLEARANCE
• Decarbonize the piston ring and piston ring groove.
• Measure the side clearances of the 1st piston ring using the
thickness gauge.
• If any of the clearances exceed the limit, replace both the pis-
ton and piston ring.
09900-20803: Thickness gauge
09900-20205: Micrometer (0 – 25 mm)
Piston ring-to-groove clearance:
Service Limit (1st): 0.180 mm (0.007 in)
Piston ring groove width:
Standard (1st) : 1.01 – 1.03 mm (0.0398 – 0.0406 in)
(Oil) : 1.51 – 1.53 mm (0.0594 – 0.0602 in)
Piston ring thickness:
Standard (1st) : 0.97 – 0.99 mm (0.0382 – 0.0390 in)
PISTON RING FREE END GAP AND PISTON RING END GAP
• Measure the piston ring free end gap using the vernier cali-
pers.
• Next, fit the piston ring squarely into the cylinder and measure
the piston ring end gap using the thickness gauge.
• If any of the measurements exceed the service limit, replace
the piston ring with a new one.
Piston ring free end gap:
Service Limit (1st): 5.7 mm (0.22 in)
09900-20101: Vernier calipers (150 mm)
Piston ring end gap:
Service Limit (1st): 0.50 mm (0.020 in)
09900-20803: Thickness gauge
