Clevite MS-1804P-.25MM High Performance Engine Crankshaft Main Bearing Set

The Clevite MS-1804P-.25MM is a high-performance crankshaft main bearing set featuring P-Series construction designed for demanding racing and performance applications. This bearing set utilizes a 180-degree oil groove design in the upper shell to optimize oil film thickness while ensuring adequate oil delivery to connecting rod bearings.

P-Series Performance Features:

• Maximum eccentricity design for engines experiencing severe rod bore deformation at high RPM
• High crush construction for superior bearing retention under extreme conditions
• Reduced overlay thickness to prevent overlay fatigue and hen tracking
• Hardened steel backing for exceptional strength and fretting resistance
• Full groove upper bearing design to maximize oil flow to rod bearings
• TriMetal bearing construction for legendary Clevite durability
• -.25MM undersize for use with reground crankshafts

Engineered Bearing Groove Technology:

Clevite's optimized 180-degree upper shell groove provides the ideal balance between oil supply and bearing performance. This design maintains maximum oil film thickness in the loaded lower bearing shell while channeling adequate lubrication to connecting rod bearings. Extended groove designs sacrifice upper bearing performance and increase parasitic power loss without providing benefits to the critical lower bearing half.

Applications:

P-Series main bearings are the ideal choice when rod bearing oil starvation is evident (indicated by surface polishing, smearing, or discoloration at the bearing center), or when higher eccentricity is needed to narrow bearing contact patterns. Use P-Series components in extreme high-RPM applications where rod bore distortion causes nearly full parting-line-to-parting-line shaft contact with standard bearings.

This bearing set is engineered for professional racing teams and serious performance builders who demand maximum durability under the most severe operating conditions.