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ACL Race Series Main Bearings are engineered for high-performance Mazda and Ford applications, offering the durability and precision required for motorsport and high-RPM builds. Designed with a tri-metal structure and performance-enhancing features, these bearings deliver consistent oil clearance, improved fatigue strength, and optimal support under extreme load.
Key Features
Trimetal construction with reduced-thickness overlay for superior fatigue resistance
Standard (STD) size; available in undersizes (.025, .25, .50)
Hardened steel backing for improved bearing retention
Increased crush and eccentricity to handle bore distortion at high RPM
Flash plating eliminated to enhance heat transfer
3/4 groove design to improve oil flow and load surface area
Tight wall tolerances for consistent oil clearance
Enlarged chamfers to fit performance crankshafts
Direct-fit lower-half set for quick installation
Technical Details
Bearing Type: Main Bearings
Size: Standard (STD)
Tunnel Diameter: 53.998 – 54.018 mm
Shaft Diameter: 49.938 – 49.956 mm
Max Wall Thickness: 2.013 mm
Max Length: 17.63 mm
Half Type: Lower
Weight: 0.23 kg
Fitment Information
Compatible with a wide range of Mazda and Ford 4-cylinder engines from the B-series and Z-series families, including:
Mazda MX-5 Miata – BP-ZE, BP-4W, BP-Z3, BP-Z3T
Mazda 323 / Protege – B6T, B6D, B6, B5, B3, BPD, BP-T, BP, Z5-DE, ZL-VE, ZM-DE
Mazda 121, Meteor – B1, B3, B5-ME, B5-MI
Ford Capri, Laser, Festiva – Mazda B6T, B6D, B6Y, B5, B3
Kia Mentor – Mazda B5-ME, B5-MI (shared platforms)
Note: Always confirm crankshaft and block specifications for precise fitment.
What’s Included
(1) Set of ACL Race Series standard-size main bearings (lower halves only)
