Sealed Power 4923MA60 A-Series Bi-Metal Aluminum Crankshaft Main Bearing Set 0.060 in. Undersize

The Sealed Power 4923MA60 is a Vintage A-Series bi-metal aluminum crankshaft main bearing set designed for classic and vintage engine rebuilds. Engineered for applications over 35 years old, this set delivers like-new performance and longevity through advanced metallurgy and precision manufacturing. The 0.060 in. (1.50 mm) undersize crankshaft journals make this an ideal choice for engines that have been reground to this dimension.

The bearing surface alloy combines aluminum, tin, and a small percentage of silicon, laid over a high-strength 1010 steel backing. This construction delivers superior seizure resistance compared to tri-metal bearings, improved corrosion resistance, tighter wall variance control, and reduced debris embedding — all of which help protect crankshaft journal surfaces over the long term. The silicon content also provides a self-polishing effect that can smooth journals that have not been fully optimized during machining.

Key Features:

• A-Series bi-metal aluminum alloy bearing material
• 0.060 in. (1.50 mm) crankshaft undersize
• Upper and lower half-groove oil grooves for full lubrication coverage
• High-strength 1010 steel backing for structural rigidity
• Greater seizure resistance than traditional tri-metal bearings
• Silicon additive minimizes debris embedding and smooths journal surfaces
• Exacting tolerances meet or exceed OEM specifications
• ISO and QS certified manufacturing
• Stock thrust bearing oversize included

Cross-Reference Part Numbers: Clevite MS540P, Clevite MS963P, ACL 5M540P, TRW MS2540, King Engine Bearings MB558AM, Vandervell VP796, Enginetech BC321J, Michigan Bearings 867T

Sealed Power Vintage engine components are purpose-built for classic engine restoration, combining modern material science with application-specific precision to ensure reliable, long-lasting rebuilds.