Piston Fitting
| 1 - Cylinder Bore Diameter Grade Markings |
| 2 - Upper Main Bearing Journal Diameter Grade Markings |
The pistons are "select fit" to achieve proper oil clearance. Engine block cylinder bore diameter grade markings are stamped into the exhaust side of the engine block on the rear drainback near the deck face. These marks are read from left to right, corresponding with cylinder number 1, 2, 3, 4, 5 and 6.
Engine block cylinder bore diameter grade markings correspond to specific cylinder bore diameters. The chart below identifies the two engine block grade markings and their associated cylinder bore diameters.
| Grade | Cylinder Bore Diameter mm (in.) | |
|---|---|---|
| Metric | Standard | |
| 1 | 83.990 - 84.000 mm | 3.3067 - 3.3071 in. |
| 2 | 84.000 - 84.010 mm | 3.3071 - 3.3075 in. |
| 1 - Piston Size |
The piston is marked with the piston size on the piston crown. The pistons are available in two different sizes in order to achieve the desired oil clearance. Select the piston size that corresponds to the engine block cylinder bore diameter grade markings for each cylinder.
The chart below identifies the two piston sizes.
| Grade | Piston Size mm (in.) | |
|---|---|---|
| Metric | Standard | |
| 1 | 83.950 - 83.960 mm | 3.3051 - 3.3055 in. |
| 2 | 83.960 - 83.970 mm | 3.3055 - 3.3058 in. |
| 1 - Coating Material |
A coating material is applied to both piston skirts after the final piston machining process. Piston installation into the cylinder bore requires 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.