Cummins 3945918 Main Bearing Set 0.25mm

The Cummins 3945918 is a 0.25mm (0.010 inch) oversize main bearing set designed for C-series 8.3 liter diesel engines including 6C, 6CT, 6CTA, ISC, ISL, QSC, and QSL models. The set comprises seven bearing pairs: six standard main bearing pairs and one thrust washer pair for crankshaft end-play control. Technical specifications include an oil hole diameter of 6.00mm, wall thickness of 3.80mm, and bearing width of 32.01mm. Construction utilizes aluminum-based alloy (tri-metal or bi-metal depending on supplier) on steel backing for optimal embeddability, conformability, and fatigue resistance under heavy-duty cyclic loads. This part serves as a direct replacement for Cummins OEM numbers 3945918 and 3800271. It is commonly required during major engine overhauls where crankshaft journals have been ground to 0.25mm undersize. Applications span construction machinery, industrial equipment, and on-highway trucks equipped with the 8.3L platform.