Clevite MS-804HX High Performance Engine Main Bearing Set

The Clevite MS-804HX is a high-performance main bearing set engineered for racing and competition engines. This H-Series bearing features extra clearance (HX suffix denotes .001" additional clearance) for standard size crankshafts, making it ideal for select fitting and accommodating thermal expansion in high-performance applications.

H-Series Design Features:

• Medium eccentricity for optimal load distribution and contact patterns
• High crush design for maximum bearing retention
• Hardened steel backing for enhanced strength and durability
• Thin overlay construction to prevent overlay fatigue
• Enlarged chamfers for greater crankshaft fillet clearance
• No flash plating for improved bearing seating
• Standard 180-degree upper shell grooving for optimal oil film thickness

Performance Benefits:

H-Series bearings were originally developed for NASCAR-type racing but are suitable for all competition engines. The 180-degree groove design in the upper shell provides the best overall performance by maintaining oil supply to connecting rod bearings while maximizing oil film thickness in the loaded lower bearing area. This design reduces peak oil film pressure and horsepower loss compared to full-grooved alternatives.

The medium eccentricity design makes H-Series bearings the ideal choice for engines running medium to high RPM ranges. Use these bearings with crankshafts featuring oversize fillets and when contact patterns need to cover the optimal 2/3 to 3/4 of the bearing surface. The HX extra clearance variant allows for precise bearing clearance control and accommodates stroker cranks or thermal expansion in high-output applications.

TriMetal Construction:

Built with Clevite's legendary TriMetal technology featuring a hardened steel back, high-strength intermediate layer, and precision overlay engineered to resist fatigue in extreme racing conditions.