ACL 5M8312HO/S2-STD +0.002" Oversize Main Bearing Set for Subaru/Toyota FA/FB

Vehicle Fitment

• Subaru BRZ / Scion FR-S / Toyota 86 (FA20/FA24) - 2013-2024
• Subaru Crosstrek (FB20) - 2016-2017
• Subaru Forester (FB25) - 2014-2018
• Subaru Impreza (FB20) - 2012-2016
• Subaru Legacy (FB25) - 2013-2019
• Subaru Outback (FB25) - 2013-2019
• Toyota GR86 (FA24) - 2022-2025

Features

• Race-series tri-metal construction for superior strength and durability
• +0.002" S2 housing oversize for line-bored or machined blocks
• Tight, consistent wall tolerances for precise oil clearance
• Increased eccentricity to maintain stable oil film at high RPM
• 3/4-groove design improves load distribution and oil flow
• No flash plating on bearing back for optimal heat transfer
• Raised crush height ensures proper bearing retention
• Enlarged ID chamfers accommodate performance crankshaft fillets

Specifications

• Part Number: 5M8312HO/S2-STD
• Bearing Size (Journal): Standard (STD)
• Housing Oversize: +0.002" (S2)
• Oil Clearance: Standard / Race spec
• Half-Shell Type: Identical upper and lower halves
• Material: Tri-metal (steel backing, copper-lead intermediate, lead/tin overlay)
• Max Shaft Diameter: ~68.009 mm
• Max Tunnel Diameter (Housing): ~73.067 mm
• Max Wall at Crown: ~2.53 mm

Included Components

• 5x main bearing shells (complete set for one engine)

Product Description

The ACL 5M8312HO/S2-STD is a high-performance Race-Series main bearing set designed for Subaru and Toyota FA and FB-series flat-4 engines. Its +0.002" housing oversize (S2) ensures a precise fit for blocks that have been line-bored or machined, providing optimal bearing clearance and retention.

Constructed from tri-metal material, these bearings offer excellent fatigue resistance and durability under high-stress and high-RPM conditions. The 3/4-groove design promotes effective oil distribution while increased eccentricity helps maintain a stable oil film during aggressive engine operation.

Perfect for performance and race engine builds, this bearing set supports a wide range of vehicles, including Subaru BRZ/FR-S/86, Crosstrek, Forester, Impreza, Legacy, Outback, and Toyota GR86. It delivers consistent reliability, improved load handling, and long-lasting performance for tuned or rebuilt engines.