Fitting Pistons
- Inspect pistons and replace any showing signs of excessive wear, wavy ring lands, or fractures. When measuring piston for side clearance or taper, measurement must be made at centerline of pin bore and 90° from piston pin hole.
- Maximum clearance is .0003-.0017" (.007-.043 mm). Check piston-to-bore clearance by measuring piston and bore diameters. Ensure piston and cylinder bore are clean, dry and at room temperature 70°F (21°C) during measurement.
- Measure diameter of bore at top, middle and bottom with gauge at right angle and parallel to centerline of engine. Inspect cylinder walls for scoring, roughness or other signs of wear. Check bore for out-of-round and taper. Cylinder bore out-of-round should not be more than .0010" (.025 mm).
- Cylinder bore taper should not be more than .0003" (.008 mm) at top and .0007" (.018 mm) at bottom. If cylinder wall is severely marred or worn, refinishing will be needed. If cylinder bore measurements differ by .0005" (.013 mm), bore cylinder block to next oversize.
- Before refinishing, ensure that main bearing caps are in place and tightened to avoid distortion during boring operation. Pistons are available in standard, standard high limit and .010"oversize.