ENGINE 3-55 PISTON RING-TO-GROOVE CLEARANCE • Measure the side clearances of the 1st and 2nd piston rings using the thickness gauge. • If any of the clearances exceeds the limit, replace both the piston and piston rings. 09900-20803: Thickness gauge 09900-20205: Micrometer (0 – 25 mm) Piston ring-to-groove clearance: Service Limit (1st) : 0.180 mm (0.0071 in) (2nd): 0.150 mm (0.0059 in) Piston ring groove width: Standard (1st) : 1.30 – 1.32 mm (0.0512 – 0.0520 in) (2nd): 0.81 – 0.83 mm (0.0319 – 0.0327 in) (Oil) : 1.51 – 1.53 mm (0.0594 – 0.0602 in) Piston ring thickness: Standard (1st) : 1.08 – 1.10 mm (0.0425 – 0.0433 in) (2nd): 0.77 – 0.79 mm (0.0303 – 0.0311 in) E PISTON RING FREE END GAP AND PISTON RING END GAP L • Measure the piston ring free end gap using the vernier cali- pers. P • Next, fit the piston ring squarely into the cylinder and measure M the piston ring end gap using the thickness gauge. • If any of the measurements exceeds the service limit, replace the piston ring with a new one. A Piston ring free end gap: S Service Limit (1st) : 5.2 mm (0.20 in) (2nd): 6.4 mm (0.25 in) 09900-20102: Vernier calipers Piston ring end gap: Service Limit (1st) : 0.50 mm (0.020 in) (2nd): 0.50 mm (0.020 in) 09900-20803: Thickness gauge