Clevite MS-1951P-.25MM High Performance Main Bearing Set Undersize

The Clevite MS-1951P-.25MM is a high-performance engine crankshaft main bearing set designed for demanding applications. This P-Series bearing set features .25mm undersize dimensions for use with reground crankshafts, providing proper clearances after machine work.

P-Series Performance Design:

• Full groove design in upper shells maximizes oil flow to connecting rod bearings
• High crush construction ensures maximum retention in the block
• Reduced overlay thickness prevents overlay fatigue and "hen tracking"
• Hardened steel backing provides added strength and fretting resistance
• Greater eccentricity narrows bearing contact patterns for improved load distribution
• Optimized 180-degree upper shell grooving maintains oil film integrity while feeding rod bearings

Advanced Bearing Technology:

Clevite's tri-metal construction combines a steel back with a copper-lead intermediate layer and a lead-tin-copper overlay. This design balances strength, conformability, and wear resistance for high-performance engines. The bearing geometry is engineered to develop a proper hydrodynamic oil film, with the shaft rotating to pull oil into the loaded area and create the protective separation layer.

Application Guidance:

P-Series main bearings are ideal for high-RPM applications where rod bearing oil starvation is a concern, typically indicated by polishing and smearing of rod bearing surfaces. Use these bearings when maximum oil flow to the rods is required and when higher eccentricity is desired to optimize bearing contact patterns. The full grooved design makes this series particularly well-suited for extreme performance builds where connecting rod lubrication is critical.

This bearing set is designed for professional engine builders and racers who understand bearing selection and have diagnosed their specific lubrication requirements through bearing inspection and performance analysis.