SWITCH-TEMPERATURE 7N9785 - Caterpillar

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)
Truck Engine News SEBD6536, 04 April 1984, "New Connecting Rod and Main Bearing Used". Disregard this article. Refer to the article that follows.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.
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