King Engine Bearings MB 545AM0.25 AM-Series Crankshaft Main Bearing Set 0.25mm Undersize

The King Engine Bearings MB 545AM0.25 is an AM-Series bi-metal crankshaft main bearing set manufactured to a 0.25mm undersize specification, designed for engine rebuilds where the crankshaft journals have been ground 0.25mm undersize. This bearing set is engineered as a precision replacement for Ford engines including the N4A, NE/L/N, JCC, LCJ, and LSE engine families.

Constructed from King's proven AM-Series bi-metal material (K-783), these bearings feature a 100% lead-free aluminum silicon alloy lining equivalent to SAE-783 standard, making them an environmentally responsible and user-safe choice for low to medium load engine applications. King AM-Series main bearings are well-suited for street and marine rebuilds.

Key Features:

• AM-Series Bi-Metal Construction – Standard aluminum-based alloy (K-783), equivalent to SAE-783, for low and medium load engines
• 100% Lead-Free – Environmentally friendly and user-safe aluminum silicon formulation
• Superior Embeddability – Promotes macro-particle absorption to reduce crankshaft journal scratching and Babbitt overlay damage
• Bull's Eye Tolerance™ Technology – Precision wall thickness control to ±0.0001 inches for consistent, accurate oil clearance
• 0.25mm Undersize – Intended for use with crankshafts that have been reground 0.25mm from the original journal diameter
• OEM Cross-Reference Numbers: 6014626, 73HM6333C2A, 014HS20234025, 87370610, H853/50.25mm

King Engine Bearings has been a benchmark in precision engine bearing manufacturing since 1960, and the AM-Series line reflects that legacy of quality. These crankshaft main bearings support smooth crankshaft rotation within the engine block while establishing the correct oil film clearance critical for long-term engine health and lubrication performance.