Chevrolet Silverado / GMC Sierra. Manual — part 137

1. When honing the cylinder bores, 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 to be
removed.

Dull, dirty stones cut unevenly and generate excessive heat.

DO NOT hone to a final grade with a coarse or medium-grade stone.

Leave sufficient metal so that all the stone marks will be removed with the fine grade
stones.

Perform the final honing with a fine-grade stone and hone the cylinder bore in a cross
hatch pattern at 45-65 degrees to obtain the proper clearance.

2. During the honing operation, thoroughly check the cylinder bore.

Repeatedly check the cylinder bore fit with the selected piston.

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

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

the cylinder bore.

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

The finish marks should be clean but not sharp.

The finish marks should be free from imbedded particles or torn or folded metal.

4. When finished, the reconditioned cylinder bores should have less than or meet the specified

out-of-round and taper requirements.

5. After the final honing and before the piston is checked for fit, clean the cylinder bore with

hot water and detergent.

1. Scrub the cylinder bores with a stiff bristle brush.

2. Rinse the cylinder bores thoroughly with clean hot water.

3. Dry the cylinder bores with a clean rag.

4. Do not allow any abrasive material to remain in the cylinder bores.

Abrasive material may cause premature wear of the new piston rings and the
cylinder bores.

Abrasive material will contaminate the engine oil and may cause premature wear

CAUTION: Refer to SAFETY GLASSES CAUTION .

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

of the bearings.

6. Perform final measurements of the piston and the cylinder bore.

7. Permanently mark the top of the piston for the specified cylinder to which it has been fitted.

8. Apply clean engine oil to each cylinder bore in order to prevent rusting.

Boring Procedure

1. Before starting the honing or reboring operation, measure all the new pistons with the

micrometer contacting at points exactly 90 degrees from the piston pin centerline.

2. File the top of the cylinder block in order to remove any dirt or burrs before using any type

of boring bar.

3. Follow the instructions furnished by the manufacturer regarding use of the boring

equipment.

4. When reboring the cylinders, make sure all the crankshaft bearing caps are installed in the

original position and direction.

5. Tighten the crankshaft bearing caps to the proper torque specifications in order to avoid

distortion of the cylinder bores in the final assembly.

6. When making the final cut with the boring bar, leave 0.03 mm (0.001 in) on the cylinder

bore diameter for finish honing. This gives the required position to the cylinder clearance
specifications. Carefully perform the honing and boring operation in order to maintain the
specified clearances between the pistons, the piston rings, and the cylinder bores.

PISTON AND CONNECTING ROD DISASSEMBLE

Tools Required

J 24086-C Piston Pin Remover/Installer. See Special Tools.

Disassemble

CAUTION: Refer to SAFETY GLASSES CAUTION .

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

Fig. 462: Exploded View Of Piston Rings
Courtesy of GENERAL MOTORS CORP.

CAUTION: Refer to SAFETY GLASSES CAUTION .

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado