King Engine Bearings MB 534AM1.25 AM-Series Main Bearing Set 1.25mm Undersize Bi-Metal

The King Engine Bearings MB 534AM1.25 is an OE-replacement bi-metal main bearing set designed for the Datsun L18 engine. This set includes 5 pairs of crankshaft main bearings machined to a 1.25mm undersize, making it ideal for engine rebuilds where the crankshaft journals have been reground to restore proper clearances.

Part of King's AM-Series lineup, these bearings utilize King's standard aluminum-based bi-metal construction — the softest material in King's range — engineered specifically for passenger car engines operating under low to medium loads. The aluminum alloy overlay delivers excellent conformability and embeddability, helping the bearing conform to minor surface irregularities and absorb micro-particles that could otherwise damage crank journals.

Key Features:

• OE Replacement Design: Direct-fit replacement engineered to factory specifications for the Datsun L18 engine
• Bi-Metal Aluminum Construction: Lead-free aluminum-based material provides a balance of softness, conformability, and durability
• 1.25mm Undersize: Sized for crankshafts reground 1.25mm under standard to restore proper oil clearance
• Superior Embeddability: Reduces crank journal scratching and protects Babbitt overlays from macro-particle damage
• Tight Tolerance Control: Manufactured to within ±0.0001 inches for precise oil clearance and reliable fitment
• Lead-Free Material: Environmentally safe composite with no lead content
• Complete Set: Includes 5 pairs of main bearings to service the full engine

Available in a full range of sizes — Standard, 0.25mm, 0.50mm, 0.75mm, 1.0mm, 1.25mm, and 1.5mm undersize — the MB 534AM series covers a wide spectrum of crankshaft regrind dimensions. King Engine Bearings are manufactured to exacting standards and are trusted by engine builders worldwide for both street rebuilds and performance applications.