What does '.50mm oversized' mean for these main bearings?

This means the bearings are slightly larger than the standard size. They are intended for use when the engine's crankshaft journals have been machined down by 0.50mm (approximately 0.020 inches) during an engine rebuild to ensure proper oil clearance and fit.

What is the tri-metal overlay on these bearings?

The tri-metal overlay is a common bearing material design that uses three layers of different metals. This construction helps to provide a good balance of strength, conformability, and embeddability, which is crucial for reducing friction and wear in high-performance engines.

Are these bearings sold individually or as a set?

These ACL main bearings are sold as a complete set for the S65B40 engine, which includes all the necessary bearings for a full engine rebuild.

2008-2013 BMW M3 Main Bearings | ACL 5M1581H-.50

Name: ACL BMW S65B40 4.0L V8 .50mm Oversized Main Bearings
Brand: ACL
SKU: acl-acl-bmw-s65b40-4-0l-v8-50mm-oversized-main-bearings-t14-719911
Price: 263.94 USD
Availability: BackOrder

ACL BMW S65B40 4.0L V8 .50mm Oversized Main Bearings

$263.94

On Backorder

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

Fits 2008-2013 BMW M3. ACL .50mm oversized main bearings for the S65B40 4.0L V8 engine. Essential for engine rebuilds.

Key Features

Fits 2008-2013 BMW M3.
ACL .50mm oversized main bearings for the S65B40 4.0L V8 engine.
Features a tri-metal overlay for improved lubrication and wear resistance.
Designed to be used with a crankshaft that has been machined to a .50mm undersize.

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Fits this vehicle

BMW M3 2008-2013

Product Details

When you're rebuilding the high-revving S65B40 4.0L V8 in your 2008-2013 BMW M3, getting the main bearings right is critical. These .50mm oversized main bearings from ACL are built to handle the demands of that engine. They are designed to provide a precise fit and reliable performance for your rebuild project.

ACL uses a tri-metal overlay on these bearings, which is a common and effective design for performance engines. This overlay helps to distribute oil evenly across the bearing surface, reducing friction and wear, especially under high loads. The .50mm oversize means these are intended for use when the crankshaft journals have been machined down by 0.020 inches (which is half of 0.50mm), ensuring a proper clearance for a rebuilt engine. This is a well-built component that's a popular choice for M3 owners undertaking engine work.

When installing these bearings, it's important to follow the manufacturer's specifications for oil clearance and torque. Proper installation is key to ensuring the longevity and performance of your engine rebuild.