Clevite MB-3852HL(25) H-Series Tri-Metal Main Bearing Set

The Clevite MB-3852HL(25) is a high-performance H-Series main bearing set designed for NASCAR and competition engines. This tri-metal bearing features a 180-degree upper shell oil groove that provides optimal oil film thickness while delivering adequate lubrication to connecting rod bearings.

H-Series Performance Features:

• Medium eccentricity design with high crush for maximum bearing retention
• Hardened steel back construction for superior strength and resistance to fretting
• Thin overlay design to prevent overlay fatigue and "hen tracking"
• Enlarged chamfers for greater crankshaft fillet clearance
• Non-flash plated for improved bearing seating and contact
• Standard 180-degree upper half grooving for optimal oil film development

Advanced Bearing Technology:

This bearing set utilizes proven tri-metal construction that balances durability with performance. The 180-degree groove configuration has been extensively tested and provides the best overall design for performance engines—a shorter 140-degree groove offers only marginal gains to the upper shell, while extended grooves into the lower half reduce upper bearing performance without benefiting the lower half. The design also minimizes horsepower loss and peak oil film pressure.

Application Guide:

H-Series bearings are ideal for crankshafts with oversized fillets and engines operating in medium to high RPM ranges. Use these bearings when contact patterns from P-Series parts are too narrow—ideal contact patterns should cover 2/3 to 3/4 of the bearing surface. The medium eccentricity design provides balanced performance for most high-performance applications. If you're uncertain which performance bearing series to choose, H-Series bearings are the recommended starting point.

This main bearing set is compatible with standard 180-degree grooving configurations and provides the proven reliability that professional engine builders trust for competition applications.