ACL Race bearings, BMW N54 / N55 engines, main crankshaft bearings

ACL Race Series – unique combination of design, metallurgy and engineering come together to deliver high performance bearings.

These trimetal engine bearings are designed to withstand higher RPM conditions, ACL Race Series Engine Bearings are available for many of the popular 4, 6 & 8 cylinder applications. Bearing kit includes bearings for one engine, e.g. one conrod bearing set for 6cyl includes 12 parts.

• 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 wall tolerances to help you maintain consistent clearances.
• Enlarged ID chamfers on bearing edges where required to accommodate large fillet radius on performance crankshafts.

Available sizes (may vary depending on the engine model)
STD, Standard size
0,25 oversize when light machining is needed for the crankshaft.
0,50 oversize when significant machining is needed for the crankshaft.
HX special size to provide +0.025 of extra tolerance. Often used with factory new crankshaft.

For example: Engine with stock tolerance of 0.03, the tolerance tuner is aiming for would be from 0.05 to 0.06. HX bearing ables to reach this tolerance without unnecessary machining.

ACL RACE is an exceptional high performance bearing for any tuned engine.

Comparison of bearing materials, most OEM bearings are of Lead or Aluminium Tin type

Check more from ACL catalog available for download below (PDF)