Clevite MS-1038HX High Performance Main Bearing Set

The Clevite MS-1038HX is a high-performance engine crankshaft main bearing set designed for competition engines and demanding applications. This H-Series bearing features a medium level of eccentricity, high crush for maximum retention, and a hardened steel back with thin overlay construction to prevent overlay fatigue.

H-Series Design Features:

• Medium eccentricity for optimal bearing contact patterns
• High crush design ensures maximum bearing retention
• Hardened steel back construction for added strength
• Thin overlay prevents overlay fatigue and hen tracking
• Enlarged chamfers provide greater crankshaft fillet clearance
• No flash plating for improved bearing seating
• Standard 180-degree upper half grooving for optimal oil film development
• HX designation indicates .001" extra clearance for select fitting

Performance Engineering:

H-Series bearings utilize a proven 180-degree groove design in the upper main shell, which research shows provides the best overall bearing performance. This configuration maintains maximum oil film thickness in the loaded lower bearing while still providing adequate oil supply to the connecting rods through the upper shell. The design avoids the performance penalties associated with extended grooving, including increased horsepower loss and peak oil film pressure.

Application Recommendations:

These bearings are ideal for engines with crankshafts featuring oversize fillets and operating in medium to high RPM ranges. The H-Series design is the recommended starting point when selecting performance bearings, as the medium eccentricity provides contact patterns covering 2/3 to 3/4 of the bearing surface—the ideal range for most performance applications. The extra clearance HX variant allows for precision fitting and accommodates thermal expansion in high-performance builds.

The Clevite MS-1038HX combines legendary TriMetal bearing construction with NASCAR-proven design features, making it suitable for all types of competition engines while providing the durability needed for sustained high-performance operation.