For 1990-2009 cars

1. Clean the sludge and carbon from the following parts:

• | The piston

• | The piston pin

• | The connecting rod

Caution: Bodily injury may occur if the carburetor cleaning fluid is exposed to the skin or if the fumes are inhaled.

Important: It is essential that the piston ring grooves are cleaned of carbon to the bare metal.

2. Clean the varnish from the piston pin by soaking it in carburetor cleaning solution.

Important: Do not scrape the piston skirt.

3. Inspect the connecting rod for bending or twisting.
4. Install the connecting rod cap.
5. Place the connecting rod assembly on a checking fixture and check for bending or twisting.
6. Do not attempt to straighten the connecting rod. The connecting rods should not be bent more than 0.18 mm (0.007 in) for every 76.2 mm (3.00 in) of rod length. The connecting rods should not be twisted more than 0.038 mm (0.0015 in) for every 25.4 mm (1.00 in) of rod length. Replace it, if it is bent or twisted.
7. Check new connecting rods before using them.
8. Inspect the outside of the connecting rod bearing and the ID of the connecting rod lower end for wear indicating high spots in the connecting rod lower end.
9. Inspect the upper end for scoring.
10. Inspect the piston pin for the following conditions:

• | Scoring

• | Galling caused by improper installation

• | Fit in the connecting rod and piston

11. Inspect the piston for the following conditions:

• | Scoring of the skirt

• | Cracks

• | Broken ring groove lands

• | Wear

Important: When fitting pistons, both the piston and the cylinder bore condition must be considered together. Production and service pistons have the same nominal weight and can be intermixed without affecting engine balance. If necessary, used pistons may be fitted selectively to any cylinder of the engine, providing they are in good condition and the same weight. Do not cut oversize pistons down or engine balance will be affected. Finish hone when selecting the piston.

12. Measure the piston diameter. When measuring piston for size or taper, measurement must be made as shown with the piston pin removed. If worn or damaged, replace with a standard or oversize piston.
13. Measure the cylinder bore, with a telescoping gauge. If worn beyond specifications, rebore and hone to size.
14. Subtract the piston diameter from the cylinder bore diameter in order to determine the piston-to-bore clearance.
15. Compare the piston-to-bore clearance with specifications in order to determine if the clearance is in acceptable range.
16. If a used piston is not acceptable, check the service piston sizes and determine if a new piston can be selected. Service pistons are available in standard, and several oversizes.
17. If the cylinder bore must be reconditioned, measure the new piston diameter then hone the cylinder bore to the correct clearance.
18. Select the new piston and mark the piston in order to identify the cylinder for which it was fitted.
19. Measure the piston pin bore diameter with an inside micrometer.
20. Measure the piston pin diameter with a micrometer.
21. Subtract the piston pin bore diameter from the piston pin diameter in order to determine the clearance.
22. Compare the clearance with specifications in order to determine if clearance is in an acceptable range. Replace the piston assembly if it is not acceptable.

Important: Do not reuse piston rings. Fit rings in order to match the cylinder they will be used in.

23. Place the piston into the cylinder at the bottom of the ring travel.
24. Place a piston ring on top of the piston.
25. Back off the piston.
26. Measure the ring gap. If the gap is below specification, increase the gap by carefully filing off excess material.

Important: Do not attempt to cut the ring groove, although high spots in the ring groove may be cleaned up by the careful use of a point file.

27. Measure the piston ring side clearance.
28. Roll the piston ring around the groove in which it is to be installed, and measure the side clearance. If the ring is too thick, try another ring.