Clevite MS-667HX High Performance Engine Main Bearing Set

The Clevite MS-667HX is a high-performance engine crankshaft main bearing set designed for racing and competition engines. This H-Series bearing features optimized 180-degree upper shell grooving that provides superior oil film development while maintaining maximum load capacity in the lower bearing shells.

H-Series Performance Features:

• Medium eccentricity design for optimal contact patterns covering 2/3 to 3/4 of bearing surface
• High crush construction ensures maximum bearing retention under extreme conditions
• Hardened steel backing provides added strength and resistance to fretting
• Reduced overlay thickness prevents overlay fatigue and hen tracking
• Enlarged chamfers accommodate oversize crankshaft fillets
• HX designation indicates .001" extra clearance for standard size shafts and select fitting
• Non-flash plated for improved seating and bedding-in performance

Advanced Bearing Design:

Clevite's engineering research demonstrates that the 180-degree groove in the upper main shell provides the best overall performance by maintaining oil supply to connecting rod bearings while preserving critical oil film thickness. The ungrooved lower shell maximizes load-carrying capacity where it's needed most, resulting in improved bearing life and greater safety margins.

Ideal Applications:

The H-Series is the recommended starting point for most performance builds and is specifically designed for NASCAR-type racing and all forms of competition engines. Use these bearings with crankshafts featuring oversize fillets and in medium to high RPM applications. The HX extra clearance variant is perfect for precision engine assembly and select fitting procedures.

Clevite TriMetal construction combines a hardened steel back, copper-lead alloy intermediate layer, and lead-tin-copper overlay for exceptional strength, conformability, and wear resistance under severe racing conditions.