- Engine:
- 1673C (S/N: 69D1-UP)
- 1673C (S/N: 76R1-UP)
- 3306B (S/N: 5KD1-UP; 63Z1-UP)
- 3306C (S/N: 7RJ1-UP; 9TL1-UP; 3KS1-UP; 2AZ1-UP)
Description of Change: New connecting rods and main bearings are now used in the rod and piston groups and the crankshaft groups on 3306 Truck Engines.
The new bearings have a different design, which uses a copper material to bond the lead and the tin overlay to the aluminum bearing material. After the lead and the tin overlay is worn, the copper bond will decrease scuffing during lack of lubrication. Cold starts, failure to prelube after oil changes and low oil levels will result in a lack of lubrication. During normal engine operation, the lead and the tin overlay will be worn in some areas before the engine is overhauled.
Previously, a nickel material was used to bond the overlay to the aluminum bearing material.
In the future, the undersize bearings will be the copper bond and the oversize bearings will be the copper bond. Currently, the bearings are the nickel bond.
Adaptable To: The new bearings and the former bearings are shown in Table 1.
| Size | New Part Number | Former Part Number |
| Connecting Rod Bearings | ||
| Standard | 4W-5739 | 8N-8219 |
| 0.25 mm (0.0010 inch) undersized | 8N-8221 | 8N-8221 |
0.51 mm (0.020 inch) undersized |
8N-8222 | 8N-8222 |
0.76 mm (0.030 inch) undersized |
8N-8223 | 8N-8223 |
| Main Bearings | ||
| Standard | 232-3233 | 8N-8224 |
0.25 mm (0.0010 inch) undersized |
8N-8225 | 8N-8225 |
0.51 mm (0.020 inch) undersized |
8N-8226 | 8N-8226 |
0.76 mm (0.030 inch) undersized |
8N-8227 | 8N-8227 |
0.51 mm (0.020 inch) oversized |
8N-8228 | 8N-8228 |
0.25 mm (0.0010 inch) undersized 0.51 mm (0.020 inch) oversized |
8N-8229 | 8N-8229 |