Piston Inspection
- Measure diameter of piston skirt 1.57" (40 mm) below piston head, at a point 90° to piston pin bore. Measure cylinder bore diameter near bottom of bore, where least wear occurs.
- Difference between cylinder bore diameter and piston diameter must not exceed .0018-.0026" (.045-.065 mm). If clearance exceeds limits, replace pistons. Variation between bore diameters should be .0008" (.02 mm) or less.
- Measure weight of all assembled piston and rod assemblies. Variation in weight between assemblies must not exceed 0.42 oz. (0.01 kg). If correction is necessary, adjust by swapping parts between assemblies, other than piston and piston pin.
- Oversize pistons are available in 0.020" (0.5 mm) and 0.040" (1.0 mm) for all models.
I-MARK PISTON SIZE CODE CHART
| Piston Size | Piston Grade | Piston 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) |
| .5 mm O.S. | A, B | 3.3246-3.3254 (84.445-84.465) |
| 1.0 mm O.S. | A, B | 3.3443-3.3451 (84.945-84.965) |
IMPULSE PISTON SIZE CHART
| Piston Size | Piston Diameter In. (mm) |
|---|---|
| Standard | 3.425-3.426 (87.000-87.040) |
| 0.5 mm O.S. | 3.444-3.445 (87.500-87.520) |
| 1.0 mm O.S. | 3.464-3.465 (88.000-88.020) |
P'UP PISTON SIZE CODE CHART
| Piston Size | Piston Grade | Piston Diameter In. (mm) |
|---|---|---|
| Standard | A | 3.4169-3.4173 (86.945-86.955) |
| Standard | B | 3.4173-3.4177 (86.956-86.965) |
| Standard | C | 3.4177-3.4181 (86.966-86.975) |
| Standard | D | 3.4181-3.4185 (86.976-86.985) |
| 0.5 mm O.S. | A, B | 3.4365-3.4373 (87.445-87.465) |
| 1.0 mm O.S. | A, B | 3.4562-3.4570 (87.945-87.965) |