Main bearing pair for Komatsu GD511A

The main bearing pair 6204-29-8100 serves as a critical interface within the engine block, supporting the crankshaft and facilitating its rotation. These bearings are engineered to maintain the precise alignment of the crankshaft while managing the mechanical loads and inertial forces generated during the combustion cycle. By providing a controlled surface for the crankshaft journals, they ensure smooth operation and effective oil film distribution throughout the engine assembly.

This component is specifically configured for the Komatsu S6D95L-1 engine, which powers the Komatsu GD511A and GD511A-1 motor graders. The 0.25 undersize designation denotes that these bearings are sized for a crankshaft that has undergone grinding or machining to remove surface imperfections, requiring a thicker bearing shell to restore proper oil clearance. Proper selection of this undersize dimension is necessary to maintain factory-specified tolerances during engine overhaul procedures.

In internal combustion engines, main bearings are installed in the engine block to cradle the crankshaft journals. They are typically supplied as a pair of semi-circular shells that fit into the main bearing caps and the engine block housing. Their function is to minimize friction between the rotating crankshaft and the stationary engine block, allowing the engine to operate under load without metal-to-metal contact.