Pistons-Fitting

BORE GAGE METHOD
1. To correctly select the proper size piston, a cylinder bore gauge, capable of reading in 0.003 mm (0.0001 inch) INCREMENTS is required. If a bore gauge is not available, do not use an inside micrometer.





Fig. 19

2. Measure the inside diameter of the cylinder bore at a point 49.5 mm (1-15/16 inches) below top of bore. Start perpendicular (across or at 90°) to the axis of the crankshaft at point A and then take an additional bore reading 90 degrees to that at point B (Fig. 19).
3. The coated pistons will be serviced with the piston pin and connecting rod preassembled. Tin coated pistons should not be used as replacements for coated pistons.





Fig. 18

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. 18). 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 inch) 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.