Piston Inspection
- Measure diameter of piston skirt 1.58" (40 mm) below piston head, at 90° to piston pin bore. Measure cylinder bore diameter near bottom of bore, where least wear occurs. Clearance between cylinder bore diameter and piston diameter must be within .0018-.0026" (.046-.066 mm). If clearance exceeds limits, replace pistons.
- Measure weight of piston and rod assemblies. Variation in weight between assemblies must not exceed .42 oz. (12 grams). If correction is necessary, adjust by changing parts between assemblies, other than piston and piston pin. Oversize (O.S.) pistons are available in .020" (.5 mm) and .040" (1 mm) for all models.
I-MARK PISTON CODE CHART
| Size | Grade | Diameter In. (mm) |
|---|---|---|
| Standard | A | 3.3049-3.3053 (83.944-83.955) |
| Standard | B | 3.3053-3.3057 (83.955-83.965) |
| Standard | C | 3.3057-3.3061 (83.965-83.975) |
| Standard | D | 3.3061-3.3065 (83.975-83.985) |
| 0.5 mm O.S. | A & B | 3.3246-3.3254 (84.445-84.465) |
| 1 mm O.S. | A & B | 3.3443-3.3451 (84.945-84.965) |
PISTON CODE CHART (ALL EXCEPT I-MARK)
| Size | Diameter In. (mm) | |
|---|---|---|
| Turbo | ||
| Standard | 3.463-3.464 (87.96-87.99) | |
| 0.5 mm O.S. | 3.482-3.484 (88.44-88.49) | |
| 1 mm O.S. | 3.502-3.504 (88.95-88.99) | |
| All Others | ||
| Standard | 3.425-3.426 (87.00-87.04) | |
| 0.5 mm O.S. | 3.444-3.445 (87.50-87.52) | |
| 1 mm O.S. | 3.464-3.465 (88.00-88.02) | |