ACL BMW S55 / N55 / N54 – M135i / M235i / M2 / M3 / M4 Standard Size Performance Main Crankshaft Bearing Set

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 Engine Bearings are available for many of the popular 4, 6 & 8 cylinder applications.Features:High strength overlay plate with reduced thickness for improved fatigue propertiesHardened 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 retentionElimination 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.