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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1162 (Engine Mechanical - 5.7L) >> Repair Instructions >> Off-Vehicle Repair Instructions >> Piston, Connecting Rod, and Bearing Installation >> Piston Selection

Piston Selection

WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.

Tools Required 

Important:  Measurements of all components should be taken with the components at normal room temperature.

For proper piston fit, the engine block cylinder bores must not have excessive wear or taper.

A used piston and pin set may be installed if, after cleaning and inspection, they are within specifications.

  1. Inspect the engine block cylinder bore for scoring or other damage.
  2. Inspect the piston and the piston pin. Refer to PISTON, CONNECTING ROD, AND BEARINGS CLEANING AND INSPECTION (PISTON AND PIN)  or PISTON, CONNECTING ROD, AND BEARINGS CLEANING AND INSPECTION (CONNECTING ROD AND BEARINGS)  or PISTON, CONNECTING ROD, AND BEARINGS CLEANING AND INSPECTION (MEASURING PISTON RING END GAP)  .
  3. With a micrometer or caliper at a right angle to the piston, measure the piston 11 mm (0.433 in) from the bottom of the skirt.
    Fig 1: Measuring Piston Diameter
    G01971042Courtesy of GENERAL MOTORS CORP.
  4. Record the piston diameter.
  5. Adjust the micrometer to the recorded piston diameter.
    Fig 2: Adjusting Micrometer To Recorded Piston Diameter
    G01971043Courtesy of GENERAL MOTORS CORP.
  6. Insert the bore gage into the micrometer and zero the bore gage dial.
  7. Use a bore gage and measure the cylinder bore diameter. Measure at a point 64 mm (2.5 in) from the top of the cylinder bore.
    Fig 3: Measuring Cylinder Bore Diameter
    G01971044Courtesy of GENERAL MOTORS CORP.
  8. Record the cylinder bore diameter.
  9. Subtract the piston diameter from the cylinder bore diameter in order to determine piston-to-bore clearance. Refer to ENGINE MECHANICAL SPECIFICATIONS - LS1  or ENGINE MECHANICAL SPECIFICATIONS - LS6 .
  10. If the proper clearance cannot be obtained, select another piston and measure for the clearances.

    If the proper fit cannot be obtained, the cylinder bore may require honing for an oversize piston or block replacement.

  11. When the piston-to-cylinder bore clearance is within specifications, permanently mark the top of the piston for installation to the proper cylinder. Refer to SEPARATING PARTS  .