What does '.25mm Oversized' mean for these main bearings?

This means the bearings are manufactured to be 0.25mm smaller in diameter than the standard factory size. They are intended for use when the engine's crankshaft journals have been machined down by 0.25mm to ensure proper oil clearance during an engine rebuild.

What vehicles does this specific main bearing set fit?

This set fits 2009-2012 BMW 750i, 2013-2016 BMW M5, 2012-2018 BMW M6, and 2011-2013, 2015-2018 BMW X5 models equipped with the 4.4L V8 engine.

Do these bearings come with installation hardware?

This product is for the main bearings only. Installation hardware, such as new main bolts or bearing cap bolts, is typically sold separately and should be replaced according to the manufacturer's service manual.

ACL BMW N63B44/S63B44 4.4L V8 .25mm Oversized Main Bearings

Specifications

Brand: ACL
Part #: 5M1573H-.25
UPC: 9315726470206

ACL BMW N63B44/S63B44 4.4L V8 .25mm Oversized Main Bearings

Name: ACL BMW N63B44/S63B44 4.4L V8 .25mm Oversized Main Bearings
Brand: ACL
SKU: acl-acl-bmw-n63b44-s63b44-4-4l-v8-25mm-oversized-main-bearings-t14-719900
Price: 266.87 USD
Availability: BackOrder

$266.87

On Backorder

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

Fits 2012-2018 BMW M6. ACL .25mm oversized main bearings for 4.4L V8 engines. Essential for engine rebuilds.

Key Features

Fits 2012-2018 BMW M6, 2013-2016 BMW M5, 2009-2012 BMW 750i, and 2011-2013, 2015-2018 BMW X5.
Main bearing set designed for BMW 4.4L V8 N63B44 and S63B44 engines.
Bearings are .25mm (0.010 inch) undersize, intended for use with a machined crankshaft.
ACL is a popular brand for engine components.
Essential for engine rebuilds where crankshaft journals have been machined.

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Will this fit your vehicle?

Product Details

When you're rebuilding the engine in your BMW M6, M5, 750i, or X5 with the 4.4L V8, getting the right main bearings is critical. These ACL main bearings are built to the factory specifications, but they come in a .25mm (.010 inch) undersize. This means they're designed to be used when the crankshaft journals have been machined down to match this specific size during an engine rebuild. Using the correct undersize bearing ensures proper oil clearance, which is vital for engine longevity and performance.

ACL is a well-known name in engine bearings, and these are a solid option for your rebuild. They are made to handle the demands of the N63B44 and S63B44 engines. When your crankshaft needs to be machined, these .25mm undersize bearings are what you'll need to get your engine back together with the correct clearances. Make sure to confirm with your machine shop that they have machined the crankshaft journals to the .25mm undersize before ordering.