For 1990-2009 cars

### Boring Procedure

1. A 0.25 mm (0.01 in) oversize service piston and piston ring set are available for the LS1 engine.

Important: Do not bore the cylinder liners on the LS1 engine.

2. It is recommended to hone the cylinder to achieve proper fit for the oversize piston.

Refer to the Cylinder Honing information for the proper honing procedure.

### Honing Procedure

1. When honing the cylinders, follow the manufacturer's recommendations for equipment use, cleaning, and lubrication. Use only clean, sharp stones of the proper grade for the amount of material you remove. Dull, dirty stones cut unevenly and generate excessive heat. Do not hone to final clearance with a coarse or medium-grade stone. Leave sufficient metal so that all stone marks may be removed with fine-grade stones. Perform final honing with a fine-grade stone, honing the cylinder to the proper clearance.
2. During the honing operation, thoroughly clean the cylinder bore. Repeatedly check the cylinder bore for fit with the selected piston.

All measurements of the piston or the cylinder bore should be made with the components at normal room temperature.

3. When honing a cylinder for fit to an oversize piston, first perform the preliminary honing with a 100 grit stone.
4. Perform final cylinder honing with a 240 grit stone and obtain a 45 degree cross hatch pattern.

A 240 grit stone is preferred for final honing. If a 240 grit stone is not available, a 220 grit stone may be used as a substitute.

5. When honing to eliminate taper in the cylinder, make full strokes the complete length of the bore.

Repeatedly check the measurement at the top, the middle, and the bottom of the bore.

6. The finish marks should be clean but not sharp. The finish marks should also be free from imbedded particles and torn or folded metal.
7. By measuring the selected piston at the sizing point and by adding the average of the clearance specification, you can determine the final cylinder honing dimension required.
8. When finished, the reconditioned cylinder bores should have less than or meet the specified out-of-round and taper requirements.
9. After final honing and before the piston is checked for fit, clean the cylinder bores with hot water and detergent. Scrub the bores with a stiff bristle brush and rinse the bores thoroughly with hot water. Do not allow any abrasive material to remain in the cylinder bores. This abrasive material may cause premature wear of the new piston rings and the cylinder bores. Abrasive material will also contaminate the engine oil and may cause premature wear of the bearings. After washing the cylinder bore, dry the bore with a clean rag.
10. Perform final measurements of the piston and the cylinder bore.
11. Permanently mark the top of the piston for the specific cylinder to which it has been fitted.
12. Apply clean engine oil to each cylinder bore in order to prevent rusting.

### Deglazing Procedure

Using a ball type or self centering honing tool, deglaze the cylinder bore lightly. Deglazing should be done only to remove any deposits that may have formed. Use a 240 grit stone of silicone carbide or equivalent material when preforming the deglazing procedure.

A 240 grit stone is preferred for final honing. If a 240 grit stone is not available, a 220 grit stone may be used as a substitute.