Clevite MS-1266HG-10 High Performance Main Bearing Set

The Clevite MS-1266HG-10 is a high-performance crankshaft main bearing set engineered for demanding racing and competition applications. This H-Series bearing features full 360-degree grooving (HG designation) to maximize oil flow to connecting rod bearings in high-stress environments.

H-Series Performance Features:

• Medium eccentricity design optimized for medium to high RPM applications
• High crush construction for maximum bearing retention
• Thin overlay thickness to prevent overlay fatigue and "hen tracking"
• Enlarged chamfers provide greater clearance for crankshafts with oversize fillets
• Manufactured without flash plating for improved bearing seating
• Full 360-degree upper and lower grooving maximizes oil delivery to rod bearings
• TriMetal bearing construction for legendary Clevite strength and durability

Application Guidance:

H-Series bearings are ideal for NASCAR-style racing and all types of competition engines running in the medium to high RPM range. Use these bearings with crankshafts that have oversize fillets, or when contact patterns with P-Series bearings are too narrow. The full-groove HG configuration is specifically designed for applications requiring maximum oil flow to prevent rod bearing oil starvation, which typically manifests as polishing, smearing, or discoloration concentrated at the bearing's axial center.

The H-Series represents an excellent starting point if you're uncertain which performance bearing series to choose, offering a balanced combination of eccentricity, crush, and oiling characteristics. Ideal contact patterns should cover approximately two-thirds to three-quarters of the bearing surface.