What is the purpose of the +0.001 inch clearance on these bearings?

This small additional clearance is intended for engines where the crankshaft journals have been precisely machined and polished to a very smooth finish. It allows for a tight, yet safe, running clearance to minimize oil flow while ensuring proper lubrication and preventing seizure.

What material are these ACL connecting rod bearings made from?

These bearings utilize a tri-metal alloy overlay on a hardened steel backing. This construction is chosen for its balance of strength, embeddability, and resistance to wear, making them suitable for performance applications.

Do these bearings come with assembly lube?

This set includes the connecting rod bearings only. It is recommended to use a high-quality engine assembly lubricant during installation to ensure proper oiling upon initial startup and to protect the bearing surfaces.

ACL BMW M20/M50/M52/M54-1919CC 80.0mm Bore 66.0mm Stroke STD + .001in Clearance Conrod Bearing Set

Specifications

Brand: ACL
Part #: 6B1490HX-STD
UPC: 9315726278321

ACL BMW M20/M50/M52/M54-1919CC 80.0mm Bore 66.0mm Stroke STD + .001in Clearance Conrod Bearing Set

Name: ACL BMW M20/M50/M52/M54-1919CC 80.0mm Bore 66.0mm Stroke STD + .001in Clearance Conrod Bearing Set
Brand: ACL
SKU: acl-acl-bmw-m20-m50-m52-m54-1919cc-80-0mm-bore-66-0mm-stroke-std-001in-clearance-t14-249680
Price: 114.51 USD
Availability: BackOrder

$114.51

On Backorder — Expected to ship by Apr 23, 2026

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

ACL connecting rod bearings for BMW M20/M50/M52/M54 engines. Standard +0.001in clearance for a precise fit.

Key Features

Fits numerous BMW M20, M50, M52, and M54 engines.
Standard size with +0.001 inch clearance for precise crankshaft fitment.
Tri-metal alloy construction offers good embeddability and strength.
Hardened steel backing provides a solid foundation for the bearing material.
Designed for 80.0mm bore and 66.0mm stroke applications.
ACL Race Series bearings are a popular choice for performance engine builds.

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Will this fit your vehicle?

Product Details

When you're rebuilding or refreshing the engine in your BMW, especially models like the E30, E36, E46, or E39 equipped with the M20, M50, M52, or M54 engine, getting the connecting rod bearings right is crucial. These ACL Race Series bearings are built with a high-performance overlay and a hardened steel backing, designed to handle the stresses of performance driving and demanding engine work. They come with a standard size plus a small 0.001-inch clearance, which is ideal for engines where the crankshaft journals have been precisely machined and polished to a very smooth finish.

ACL has been making engine bearings for a long time, and their Race Series is a popular choice for tuners and mechanics. The material composition here is a tri-metal alloy that offers good embeddability and strength, helping to protect your crankshaft journals from wear. This specific set is for an 80.0mm bore and 66.0mm stroke, matching the factory dimensions for many of these BMW engines. It's important to ensure your crankshaft journals are within specification and properly prepped before installing these bearings for optimal performance and longevity.

If you're working on a performance build or a meticulous restoration, these ACL bearings are a solid option. Make sure to check your crankshaft journal dimensions and clean everything thoroughly before installation. You'll also want to have the correct assembly lube on hand to ensure these bearings get oil pressure immediately upon startup.