ACL Race Main Bearings Standard Size Position #5 Subaru 2002-2014 WRX / 2004-2021 STI | 5M8309H-STD
ACL's main bearings are made of a softer metal so that you don't wear out your crank or engine block. Additionally, a thin layer of oil lubricates the connection between the bearings and the crank allowing the crank to "float" and reduce wear. Proper support via main bearings is crucial to prevent oscillations and wear that can damage the crankshaft and other components as the motor moves further out of balance.
Bearings with extra oil clearance will absorb the stress of higher horsepower motors greater, but will see increased wear during start up. We recommend these be purchased by experienced professionals only.
Know What You Are Buying:
Subaru main bearings are specific to either a #5 or #3 journal bearing position. Journal bearing position is not VIN or year specific, it must be known prior to purchase. Please be sure which bearings you need as engine internals components are not eligible for exchange or return.