Grand Cherokee 2WD V8-4.7L VIN J (2004)
Piston: Procedures
STANDARD PROCEDURE-PISTON FITTING
1. To correctly select the proper size piston, a cylinder bore gauge, capable of reading in 0.003 mm (0.0001 in.) INCREMENTS are required. If a
bore gauge is not available, do not use an inside micrometer.
2. Measure the inside diameter of the cylinder bore at a point 38.0 mm (1.5 inches) below top of bore. Start perpendicular (across or at 90 degrees)
to the axis of the crankshaft at point A and then take an additional bore reading 90 degrees to that at point B (Fig. 70).
3. The coated pistons will be serviced with the piston pin and connecting rod pre-assembled.
4. The coating material is applied to the piston after the final piston machining process. Measuring the outside diameter of a coated piston will not
provide accurate results (Fig. 69). Therefore measuring the inside diameter of the cylinder bore with a dial Bore Gauge is MANDATORY. To
correctly select the proper size piston, a cylinder bore gauge capable of reading in 0.003 mm (0.0001 in.) INCREMENTS are required.
5. Piston installation into the cylinder bore requires slightly more pressure than that required for non-coated pistons. The bonded coating on the
piston will give the appearance of a line-to-line fit with the cylinder bore.
