King Engine Bearings MB511XP XP-Series Tri-Metal Performance Main Bearing Set

The King Engine Bearings MB511XP is a XP-Series Xtreme Performance tri-metal main bearing set engineered for high-load, extended-duration racing applications. Built on a layered copper-lead construction with a nickel barrier and a metallurgically hardened pMax Black overlay over a steel backing, these bearings deliver superior load capacity and fatigue resistance where conventional bearings fall short.

The XP Series was developed specifically for performance engines running forged steel aftermarket crankshafts under sustained high-load conditions — including circle track, off-road, and offshore racing. The pMax Black overlay is 24% harder than any conventional tri-metal race bearing, and the SecureBond adhesion process ensures exceptional stability between the bearing's top and intermediate layers.

XP-Series Key Features:

• pMax Black Tri-Metal Construction: Enhanced copper-lead intermediate layer with nickel barrier and hardened performance overlay — load capacity of 17,000 psi in the intermediate layer and 10,200 psi in the overlay
• 15%–30% Greater Load Capacity compared to traditional race bearings
• 0.0005" Hardened Performance Overlay for superior fatigue resistance under extreme loads
• SecureBond Adhesion Process: Unique bonding method that locks the top and intermediate layers together for long-term stability
• Bull's-Eye Tolerance: Wall thickness matched to ±0.0001" — the tightest tolerance in the industry
• 1/2-Grooved Upper Shell: Maintains uncompromised load capacity in the lower shell while ensuring proper oil distribution
• Narrowed Design: Main bearings are narrowed to accommodate large-radius crankshafts
• Improved Oiling: Enlarged, chamfered oil holes for enhanced oil flow and thermal management
• Medium Eccentricity: Optimizes load distribution and bearing-to-journal oil film

Applications:

• High-load, long-duration racing including circle track, off-road, and offshore
• Performance builds using forged steel aftermarket crankshafts
• Compatible with Alfa Romeo AR01608/34 engine (OEM reference)

King Engine Bearings has specialized exclusively in engine bearings since 1960, offering one of the industry's widest selections of sizes and clearance options. The MB511XP is sold as a complete main bearing set.