ACL Bearings Engine Crankshaft Main Bearing

ACL Bearings Crankshaft Main Bearings: Race-Proven Engineering for Every Build

When an engine builder reaches for a set of crankshaft main bearings, the choice of manufacturer carries real consequences. The main bearings are the critical interface between the crankshaft journals and the engine block, supporting the rotating assembly under enormous loads, high oil temperatures, and punishing RPM. ACL Bearings has built its reputation squarely on engineering these components to outlast and outperform — whether the destination is a daily-driven street car or a championship-winning race engine.

The ACL Race Series Advantage

ACL Race Series performance engine bearings are recognized as a premier brand throughout the motorsports world, with Race Series rod and main bearings serving as standard components in race engines that have set records and won championships from Mexico to Bonneville — from sport compact drift racing to small block NASCAR, IHRA, and NHRA competitions. That breadth of motorsport validation translates directly to the crankshaft main bearing lineup available here.

The unique combination of design, metallurgy, and engineering provides Race Series performance bearings with the endurance and capability to perform where others cannot. For the engine builder sourcing engine crankshaft main bearings, this means a part engineered with a deep understanding of what actually destroys bearings under load.

Key Engineering Features

ACL Race Series crankshaft main bearings incorporate several design details that set them apart from standard replacement bearings:

• 3/4 Groove Design: 3/4 grooved main bearings optimize bearing load-carrying surface area and oil flow to the con-rod bearings , ensuring the entire rotating assembly stays properly lubricated.
• High-Strength Overlay Plate: A high-strength overlay plate with reduced thickness delivers improved fatigue properties , allowing the bearing to handle repeated peak-load cycles without breaking down.
• Tight Wall Tolerances: Tight, consistent wall tolerances help the engine builder maintain consistent clearances across every journal — a critical factor when dialing in oil clearance for forced-induction or high-revving builds.
• Enlarged ID Chamfers: Enlarged ID chamfers on bearing edges, where required, accommodate the large fillet radius found on performance crankshafts , preventing edge loading that can cause premature failure.
• Increased Eccentricity: ACL Race Series performance engine bearings feature increased eccentricity to improve shape adaptation and compensate for bore distortion at high-speed operation , a refinement that proves its worth under sustained high-RPM use.
• Increased Crush: Increased crush improves bearing retention , keeping the shell firmly seated in the housing even when thermal cycling and vibration work against it.

Material Options: Trimetal and Bimetal Construction

Plain and flanged bearings are manufactured in several material options, including ACL's Duraglide F780 heavy-duty, tri-metal copper-lead material, to suit every performance requirement. The trimetal Race Series (F781) construction layers a high-strength lead overlay over a sintered copper-lead lining bonded to a steel back — a proven architecture for highly loaded crankshaft applications. For OEM-replacement applications, both foreign and domestic car manufacturers install bimetal (aluminum) bearings as standard OE components in today's engines, having made the switch from lead-content bearings for environmental considerations — a transition ACL's standard replacement line accommodates fully.

Street, Strip, and Everything Between

ACL Race bearings work well in street machines that are rarely used at maximum power but are expected to have a normal engine life, as well as in Top Fuel dragster engines where bearing loads are several hundred MPa but life is measured in seconds. With 54 SKUs in this category spanning standard and undersize dimensions for a wide range of domestic and import applications, ACL gives the engine builder the flexibility to spec the right bearing for every job.