Piston: Service and Repair
Removal Procedure1. Remove the cylinder head with the intake manifold and exhaust manifold attached. Refer to Cyliner Head Assembly; Service and Repair; Cylinder Head and Gasket.
2. Remove the oil pan.
3. Remove the oil pump/pickup tube bolts.
4. Remove the oil pump/pickup tube.
5. Remove the engine block lower support and the splash shield bolts.
6. Remove the engine block lower support and the splash shield.
7. Move the piston to the bottom of the piston stroke.
8. Mark the connecting rod cap for position.
9. Remove the connecting rod cap bolts.
10. Remove the connecting rod cap and the lower connecting rod bearing.
11. Remove the upper piston connecting rod bearing.
12. Ridge ream the cylinder wall.
Caution: Use care when handling the piston. Worn piston rings are sharp and may cause injury.
13. Remove the piston.
14. Use a piston ring expander tool to expand the piston rings.
15. Remove the piston rings.
16. Remove the piston pin from the piston and connecting rod assembly using the piston pin service set KM-427.
17. Separate the piston from the connecting rod.
Inspection Procedure
1. Inspect the connecting rod for bending or twisting. If the connecting rod is bent or twisted, replace the connecting rod.
2. Inspect the connecting rod bearings.
3. Inspect the connecting rod lower end for wear.
4. Inspect the connecting rod upper end for scoring.
5. Inspect the crankshaft rod bearing journal for wear. Refer to Crankshaft, Engine; Specifications.
6. Inspect the piston for scoring, cracks, and wear.
7. Inspect the piston for taper using a micrometer.
8. Inspect the piston for fit to the connecting rod.
9. Inspect the engine block deck surface for flatness using a straight edge and a feeler gauge. Refer to Cylinder Block Assembly; Specifications.
10. Inspect the bearing bore for concentricity and alignment using a bore gauge. Refer to Cylinder Block Assembly; Specifications. If the bearing bore is beyond specifications, replace the engine block.
11. Inspect the engine block cylinder bore for wear, runout, ridging and taper using a bore gauge. Refer to Cylinder Block Assembly; Specifications.
12. Inspect the engine block cylinder bore for glazing. Lightly hone the cylinder bore as necessary.
Installation Procedure
1. Align the notch on the piston and connecting rod so that the proper sides will be facing the front of the engine.
2. Install the piston pin guide through the piston and the connecting rod.
3. Coat the piston pin with clean oil.
4. Install the piston pin into the opposite side of the piston.
5. Install the piston pin into the piston and connecting rod assembly using the piston pin service set KM-427.
6. Select a set of new piston rings.
7. Measure the piston ring gap using a feeler gauge. Refer to Piston Ring, Engine; Specifications.
8. Increase the piston ring gap by carefully filing off excess material if the piston ring gap is below specifications.
9. Measure the piston ring side clearance using a feeler gauge. Refer to Piston Ring, Engine; Specifications.
10. If the piston ring is too thick, try another piston ring.
11. If no piston ring can be found that fits to specifications, the piston ring may be ground to size with emery paper placed on a sheet of glass.
12. Install a piston oil ring, the expander, and the second piston oil ring to the bottom ring groove of the piston.
13. Install the second compression ring to the middle ring groove of the piston.
14. Install the top compression ring to the top ring groove of the piston.
15. Use a piston ring expander to install the piston rings. Do not expand the piston rings beyond the expansion necessary for installation.
16. Stagger the piston oil rings, the oil ring rail gaps, the second compression ring, and the top compression ring in relation to the notch on the top of the piston.
17. Lubricate the cylinder wall and the piston rings with clean engine oil.
18. Install the piston using a ring compressor and a wood handle. Guide the lower connecting rod end to prevent damaging the crankshaft journal.
19. Install the connecting rod cap and bearings. Refer to "Crankshaft Main Bearing; Service and Repair.
20. Install the connecting rod cap bolts.
Tighten the connecting rod cap bolts to 35 Nm (26 ft. lbs.). Using the angular torque gauge KM-470-B, tighten the bolts one turn of 45 degrees plus one turn of 15°.
21. Install the engine block lower support bracket/splash shield bolts.
Tighten the engine block lower support bracket/splash shield bolts to 35 Nm (26 ft. lbs.).
22. Install the oil pump/pick-up tube.
23. Install the oil pump/pick-up tube bolts.
Tighten the oil pump/pick-up tube bolts to 10 Nm (89 inch lbs.).
24. Install the oil pan.
25. Install the cylinder head with the intake manifold and exhaust manifold attached. Refer to Cylinder Head Assembly; Service and Repair; Cylinder Head and Gasket.