30. Piston, Connecting Rod, and Bearing Clean and Inspect
PISTON, CONNECTING ROD AND BEARINGSCLEAN AND INSPECT
IMPORTANT: Use compressed air to dry connecting rod. DO NOT use shop lower or rag to clean rod cap and rod mating surfaces.
1. Use cleaning solvent to clean connecting rod.
2. Use cleaning solvent to clean pistons if reusing piston. DO NOT wire brush piston skirt or ring groove area.
3. Use cleaning solvent to clean piston pins if reusing piston pins. New pistons contain new piston pins.
4. Use a groove cleaner or broken ring to clean piston ring groove.
5. Inspect connecting rod for the following conditions:
^ Inspect for twists.
^ Replace if damage is evident.
^ Inspect for nicks.
^ Replace if damage is evident.
^ Inspect for cracks.
^ Replace if damage is evident.
6. Inspect pistons for the following conditions:
^ Inspect for cracked skirts.
^ Inspect for cracked piston pin bosses.
^ Inspect for cracked ring groove lands.
^ Inspect for nicks that may cause binding.
^ Inspect for burrs that may cause binding.
^ Inspect for warped ring groove lands.
^ Inspect for worn ring groove lands.
^ Inspect for eroded areas on top of the piston.
^ Inspect for worn piston pin bores.
^ Replace the piston if any of the above is evident.
7. Measure piston ring groove clearance.
8. The 1st and 2nd compression ring groove clearance specification is 0.02 - 0.04 mm (0.0008 - 0.0015 inch).
9. Replace piston if ring groove clearance is not within the proper specification.
10. The oil control ring groove clearance specification is 0.01 - 0.02 mm (0.0004 - 0.0012 inch).
11. Replace piston if ring groove clearance is not within the proper specification.
12. Use a micrometer and use an inside micrometer to measure piston pin bore-to-piston pin clearance.
13. The maximum clearance is 0.003 - 0.008 mm (0.0001 - 0.0003 inch).
14. Replace piston and replace pin if the pin bore-to-piston pin clearance is beyond the proper specification.
15. Measure piston ring end gap clearance in bore. Perform only after the cylinder has been honed.
16. The 1st and 2nd compression ring gap specification is 0.30 - 0.50 mm (0.0118 - 0.0196 inch).
17. Replace piston rings if end gap clearance is not within the proper specification.
18. The oil control ring end gap specification is 0.40 - 1.40 mm (0.0157 - 0.0551 inch).
19. Replace piston rings if end gap clearance is not within the proper specification.