Clevite Nissan 4 1189-1299cc Main Bearing Set

This Clevite Main Bearing Set, part number MS1329A25MM, is built with a 0.025 inch undersize. This specific sizing is important when you're rebuilding or repairing the engine in your 1963-1967 Nissan 411, or compatible 410, 520/521 Pickup, or Bluebird models. These bearings are crucial for supporting the crankshaft and ensuring it spins freely within the engine block. They create a thin film of oil that separates the rotating crankshaft from the stationary engine block, preventing metal-on-metal contact and wear.

Clevite uses a multi-layer construction for these bearings, combining a steel backing for strength with a bearing material designed for durability and proper oil flow. The 0.025 inch undersize means these bearings are intended for crankshafts that have been machined down by that amount to correct for wear or damage. Proper installation, including ensuring the crankshaft journals are clean and within the specified tolerance, is key to getting the most out of this well-built bearing set.