Fitting Pistons
- Five different standard pistons sizes and cylinder bore diameters are used. Pistons are marked "0", "1", "2", "3" or "4" on top of piston near Front mark. See PISTONS, PINS & RINGS SPECIFICATIONS table.
- Cylinder bore diameters are marked "0", "1", "2", "3", "4". Identification mark is located on left side of block near each cylinder bore and on oil pan gasket surface between cylinders No. 4 and 5. See Fig 1 and CYLINDER BLOCK SPECIFICATIONS table.
- To determine if piston-to-cylinder clearance is within specification, measure piston skirt diameter at right angles to piston pin center line, .87" (22.1 mm) from top of piston. Replace piston or rebore cylinder block if clearance is not within specification. See PISTONS, PINS & RINGS SPECIFICATIONS table.
- To determine amount of cylinder rebore, add piston clearance of .0031-.0039" (.08-.10 mm) or .0028-.0035" (.07-.09 mm) on turbo model, to measured piston diameter. From this figure, subtract maximum honing amount of .0008" (.020 mm).
- After honing cylinder to final fit, measure piston-to-cylinder clearance with piston and cylinder at 70°F (21°C). Clearance should be .0031-.0039" (.08-.10 mm) or .0028-.0035" (.07-.09 mm) on turbo model.
- If reusing pistons, decarbon ring grooves with groove cleaner or broken ring. Using solvent and soft brush (not wire brush), thoroughly clean piston. Check for scratches, wear or damage.
NOTE:
Pistons are available only in .50 mm oversize.