K 2500 Truck 4WD V8-454 7.4L VIN J SFI (1997)
Piston: Testing and Inspection
Piston Selection
Check the used piston-to-cylinder bore clearance in the following manner:
1. Using a telescoping bore gauge located 65 mm (2.5 inch) below the top of the cylinder bore, measure the cylinder bore diameter.
2. Measure the piston diameter at 20°C (70°F).
3. Measure the skirt at a right angle to the piston pin hole, 25 mm (1.0 inch) below the oil ring groove.
4. Subtract the piston diameter from the cylinder bore diameter in order to determine the piston-to-bore clearance.
5. Locate the piston-to-bore clearance.
6. Determine if the piston-to-bore clearance is within the acceptable range.
7. If the used piston is not acceptable determine if a new piston will fit the cylinder bore.
8. If the new piston will not bring the clearance within tolerances the cylinder bore must be reconditioned.
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Mark the piston to identify the cylinder for which it was fitted.
