Procedures
STANDARD PROCEDURE-PISTON FITTINGPiston and cylinder wall must be clean and dry. Specified clearance between the piston and the cylinder wall is 0.013 - 0.038 mm (0.0005 - 0.0015 inch). The max. allowable clearance is 0.0762 mm (0.003 inch).
Piston diameter should be measured at the top of skirt, 90° to piston pin axis. Cylinder bores should be measured halfway down the cylinder bore and transverse to the engine crankshaft center line.
Pistons and cylinder bores should be measured at normal room temperature, 21°C (70°F).
1. To correctly select the proper size piston, a cylinder bore gauge, capable of reading in.0001" INCREMENTS is required (Fig. 39). If a bore gauge is not available, do not use an inside micrometer. 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. 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 .0001" increments is required. Piston installation into the cylinder bore require 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.