Chevrolet Silverado / GMC Sierra. Manual - part 137
10. Measure the cylinder bores for taper and out-of-round.
1. Depress the plunger on the J 8087 to 7 mm (0.275 in) or until the J 8087 enters the
cylinder bore.
2. Center the J 8087 in the cylinder bore and turn the indicator dial to 0.
3. Move the J 8087 up and down the cylinder bore to determine the cylinder bore taper.
Refer to Engine Mechanical Specifications .
4. Turn the J 8087 to different points around the cylinder bore to determine the cylinder
bore out-of-round condition. Refer to Engine Mechanical Specifications .
CYLINDER BORING AND HONING
Honing Procedure
Fig. 461: Identifying Cylinder Bore Cross Hatch Pattern
Courtesy of GENERAL MOTORS CORP.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado
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
