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
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Trimetal construction with reduced-thickness overlay for superior fatigue resistance
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Standard (STD) size; available in undersizes (.025, .25, .50)
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Hardened steel backing for improved bearing retention
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Increased crush and eccentricity to handle bore distortion at high RPM
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Flash plating eliminated to enhance heat transfer
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3/4 groove design to improve oil flow and load surface area
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Tight wall tolerances for consistent oil clearance
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Enlarged chamfers to fit performance crankshafts
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Direct-fit lower-half set for quick installation
Technical Details
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Bearing Type: Main Bearings
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Size: Standard (STD)
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Tunnel Diameter: 53.998 – 54.018 mm
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Shaft Diameter: 49.938 – 49.956 mm
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Max Wall Thickness: 2.013 mm
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Max Length: 17.63 mm
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Half Type: Lower
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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:
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Mazda MX-5 Miata – BP-ZE, BP-4W, BP-Z3, BP-Z3T
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Mazda 323 / Protege – B6T, B6D, B6, B5, B3, BPD, BP-T, BP, Z5-DE, ZL-VE, ZM-DE
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Mazda 121, Meteor – B1, B3, B5-ME, B5-MI
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Ford Capri, Laser, Festiva – Mazda B6T, B6D, B6Y, B5, B3
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Kia Mentor – Mazda B5-ME, B5-MI (shared platforms)
Note: Always confirm crankshaft and block specifications for precise fitment.
What’s Included
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(1) Set of ACL Race Series standard-size main bearings (lower halves only)