What does 'undersize 0.25mm' mean for these bearings?

This means the bearings are 0.25mm smaller in diameter than a standard-sized bearing. They are intended for use when the crankshaft journals have been machined down to remove wear or damage, ensuring a proper fit on the reduced journal size.

What is the purpose of connecting rod bearings?

Connecting rod bearings sit between the connecting rod and the crankshaft. Their main job is to provide a low-friction surface for the rod to spin on, while also maintaining the critical oil clearance needed to keep the crankshaft lubricated and cool under load.

Do these bearings come with installation instructions?

While these bearings are designed as direct replacements, it is always recommended to consult your vehicle's official service manual for detailed installation procedures, torque specifications, and proper engine assembly practices.

2015-2020 BMW M4 Connecting Rod Bearings | ACL 4B1584H-.25

Name: ACL 0 Engine Connecting Rod Bearing Set
Brand: ACL
SKU: acl-acl-0-engine-connecting-rod-bearing-set-t14-630766
Price: 143.73 USD
Availability: BackOrder

ACL 0 Engine Connecting Rod Bearing Set

$143.73

On Backorder

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

Fits 2015-2020 BMW M4. ACL 0 Connecting Rod Bearing Set, undersize 0.25mm, for engine rebuilds.

Key Features

Fits 2015-2020 BMW M4, 2019-2021 BMW M2, and 2015-2018 BMW M3.
Connecting rod bearing set for engine rebuilding.
Undersize 0.25mm for use with machined crankshaft journals.
Designed to maintain proper oil clearance and reduce friction.
Well-built by ACL, a long-standing manufacturer of engine components.

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Fits these vehicles

BMW M2 2019-2021
BMW M3 2015-2018
BMW M4 2015-2020

Product Details

ACL has been making engine bearings for decades, and this connecting rod bearing set for your BMW M4 is one of their staples. These bearings are crucial for the health of your engine's rotating assembly. They sit between the connecting rod and the crankshaft, providing a smooth, low-friction surface that allows the rod to spin freely while maintaining oil pressure. When you're rebuilding an engine, especially one that's seen some miles or is being pushed harder, replacing these bearings is a key step to ensuring longevity and proper performance.

This particular set is an undersize bearing, meaning it's 0.25mm smaller than the standard size. This is used when the crankshaft journals have been machined down to remove wear or damage. The undersize dimension ensures a proper, snug fit on the machined journal, which is critical for maintaining the correct oil clearance. ACL uses well-built materials and manufacturing processes to create bearings that can handle the high loads and temperatures found in performance engines. Getting the oil clearance just right is essential for preventing premature wear and ensuring your engine runs smoothly.

When installing these bearings, it's important to have the crankshaft journals measured and verified to be within spec for this 0.25mm undersize. Always refer to your vehicle's service manual for the correct installation procedures and torque specifications. Cleanliness is also paramount during engine assembly; make sure all parts and your workspace are free of any contaminants.