King Engine Bearings MB5527AM1.5 Bi-Metal Main Bearing Set Oversize - 1.5mm

The King Engine Bearings MB5527AM1.5 is a +1.5mm oversize bi-metal main bearing set engineered for Toyota inline-4 engines using the 4A-FE, 5A-FE, and 7A-FE engine families. This set is the correct choice for engine rebuilds where the crankshaft journals have been machined 1.5mm undersize, restoring proper oil clearances and crankshaft support.

Material & Construction:

• Bi-Metal Aluminum Construction — standard aluminum-based bearing material equivalent to SAE-783, engineered for low and medium load street and daily-driven applications
• Steel backing bonded with an aluminum-tin alloy overlay for reliable load distribution and excellent conformability
• Designed to provide consistent oil film support across the full journal surface

King Bull's Eye Tolerance™ Technology:

• Combines precision machining, overplating, and computerized wall thickness monitoring
• Ensures consistent bearing wall thickness for proper oil clearance right out of the box
• Engineered for the aftermarket with a wider range of undersize options than OEM suppliers

Key Specifications:

• Part Number: MB5527AM1.5
• Oversize: +1.5mm (crankshaft journals machined 1.5mm undersize)
• Material: Bi-Metal — Aluminum (SAE-783 equivalent)
• Application: Toyota 4A-FE, 5A-FE, 7A-FE engines
• Set Contents: Full main bearing set (upper and lower shells for all main journals)

King Engine Bearings has specialized exclusively in engine bearings since 1960, applying knowledge gained from motorsport and aviation use to every bearing in its aftermarket lineup. The AM-series bi-metal bearings are ideal for stock or mildly modified street engines being refreshed or rebuilt to factory specifications.