Check Proper Size of Rings 1. Connecting rods must be in proper alignment. 2. Clean pistons. Remove carbon deposits from piston top and piston ring grooves without scratching the base metal. Signs of uneven contact or carbon deposits on one side of the piston may indicate poor connecting rod alignment. 3. Check piston rings for proper condition, ring gap, and ring groove clearance. If not as specified, replace piston rings or pistons, as required. 4. Measure pistons. Size designation is stamped into each piston top. Measurements are accomplished as shown in the illustration (perpendicular to piston pin axis). Piston size groups are shown in tables. Piston clearance at installation is 0.02 mm (0.0008 in). If the measurement of the piston and cylinder reveals a clearance approaching the wear limit, the piston and cylinder should be replaced with a set falling into the same size group. If the mating cylinder of a damaged piston does not show traces of wear or damage, it may be possible to replace the piston alone with one falling into the appropriate size (letter) group. |
