Chevrolet Silverado / GMC Sierra. Service manual — part 189

Fig. 631: Measuring Cylinder Bore
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: Measurements of all components should be taken with the

components at normal room temperature.
For proper piston fit, the engine block cylinder bores should

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

1. Use the J 8087 in order to measure the cylinder bore diameter. Measure at a point 64 mm

(2.5 in) from the top of the cylinder bore and 90 degrees to the crankshaft centerline.

Fig. 632: Measuring Bore Gauge With Micrometer
Courtesy of GENERAL MOTORS CORP.

2. Measure the J 8087 with a micrometer and record the reading.

not have excessive wear or taper.
A used piston and piston pin set may be reinstalled if, after
cleaning and inspection, the piston and piston pin are within
specifications.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

Fig. 633: Measuring Piston Outside Diameter Using Micrometer
Courtesy of GENERAL MOTORS CORP.

3. With a micrometer or caliper at a right angle to the piston pin bore, measure the piston 11

mm (0.433 in) from the bottom of the skirt.

4. Subtract the piston diameter from the cylinder bore diameter in order to determine piston-

to-bore clearance. Refer to Engine Mechanical Specifications.

5. If the proper clearance cannot be obtained, then select another piston and measure the

clearances.

If the proper fit cannot be obtained, the cylinder bore may require honing or boring.

6. When the piston-to-cylinder bore clearance is within specifications, permanently mark the

top of the piston for installation into the proper cylinder.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

Installation Procedure

1. Apply clean engine oil to the following components:

The piston

The piston rings

The cylinder bore

The bearing surfaces

Fig. 634: Compressing The Piston Rings Using J 8037
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado