Standard Procedure-Piston Fitting

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

To correctly select the proper size piston, a cylinder bore gauge, capable of reading in 0.003 mm ( .0001 in.) INCREMENTS is required. If a bore gauge is not available, do not use an inside micrometer.
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 1).

Fig 1: Measuring Engine Cylinder Bore By Bore Gauge
Courtesy of DAIMLERCHRYSLER CORP.
The coated pistons will be serviced with the piston pin and connecting rod pre-assembled.
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 2). 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 (.0001 in.) increments is required.

Fig 2: Do Not Measure Moly Coated Piston
Courtesy of DAIMLERCHRYSLER CORP.
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.