Clevite MS-909H-1 H-Series Performance Main Bearing Set

The Clevite MS-909H-1 is an H-Series performance main bearing set engineered for NASCAR-type racing and all forms of competition engines. Developed for medium to high RPM applications, these bearings feature a proven tri-metal construction with optimized design characteristics for demanding racing conditions.

H-Series Design Features:

• Medium eccentricity level for optimal contact patterns covering 2/3 to 3/4 of bearing surface
• High crush design for maximum bearing retention in the housing
• Hardened steel backing for superior strength and durability
• Thin lead-tin-copper overlay to prevent overlay fatigue
• Enlarged chamfers for increased crankshaft fillet clearance
• No flash plating for improved bearing seating
• Standard 180-degree upper shell grooving for efficient oil delivery to connecting rods

Advanced Bearing Technology:

This main bearing set utilizes optimized grooving design based on extensive performance testing. The 180-degree groove in the upper main shell provides the best overall performance by maintaining maximum oil film thickness while ensuring adequate oil supply to the connecting rods. The ungrooved lower shells develop a thicker hydrodynamic oil film, providing greater load capacity and improved bearing life under racing conditions.

Application Guidelines:

H-Series bearings are the recommended starting point for most performance and racing applications. Use these bearings with crankshafts featuring oversize fillets and in engines operating in medium to high RPM ranges. If P-Series bearings produce contact patterns that are too narrow, H-Series bearings with their medium eccentricity will provide broader, more ideal contact patterns. These bearings are designed without flash plating to ensure optimal seating and heat transfer in competition environments.

The MS-909H-1 represents decades of Clevite engineering expertise in performance bearing design, delivering the reliability and durability required for professional racing and serious performance applications.