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Standard Procedure - Piston Fitting

WARNING: This page is about a different car, the 2004 Dodge Dakota. However, it is still accessible from the selected car via links, so may be relevant.
  1. 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.
  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 1 ).
    Fig 1: Installing Bore Gauge-Typical
    G03512134Courtesy of DAIMLERCHRYSLER CORP.
  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 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.
  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.
    Fig 2: Identifying Moly Coated Piston
    G03512133Courtesy of DAIMLERCHRYSLER CORP.