ACL Main Bearing Set BMW S54 - .025mm .001" Undersized
We've found this bearing to be a cost effective alternative to the Genuine BMW Main Bearings we also carry. On the S54 engine these bearings produce a clearance of .002". While they are specified to be .001" or .25mm undersize from standard they actually fit quite well for a street engine build application.
ACL Race Series Main Bearings: The unique combination of design, metallurgy and engineering come together to deliver what drivers expect from high performance Trimetal engine bearings.
Designed to withstand higher RPM conditions, ACL Race Series Connecting Rod Bearings are available for many of the popular 4, 6 & 8 cylinder applications and feature:
* *High strength overlay plate* with reduced thickness for improved fatigue properties
* *Hardened steel backs* on all rod bearings to improve the support of the bearing lining and assist with bearing retention in the housing.
* *Increased crush* for improved bearing retention
* *Elimination of flash plating* on the back of the bearings to improve heat transfer through the bearings and to maximize the grip between the bearings and its housing.
* *Increased eccentricity* to compensate for bore distortion at high rpm and to assist in the formation of hydrodynamic oil films.
* *3/4 grooved Main Bearings* to optimize bearing load carrying surface area and oil flow to the conrod bearings.
* *Tight consistent wall tolerances* to help you maintain consistent clearances.
* *Enlarged ID chamfers* on bearing edges where required to accommodate large fillet radius on performance crankshafts.