ACL BMW N63B44/S63B44 4.4L V8 .025mm Oversized Main Bearings
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ACL BMW N63B44/S63B44 4.4L V8 .025mm Oversized Main Bearings

ACL
ACL5M1573H-.025
9315726470190
Bearings
7 Units In Stock - Ships Next Business Day
ACL, Bearings, Engine, Engine Block
$ 449.06
$ 449.06

SKU: 5M1573H-.025 / UPC: 9315726470190

ACL BMW N63B44/S63B44 4.4L V8 .025mm Oversized Main Bearings

The ACL Race Series main bearings deliver precise crankshaft support and consistent oil flow in high-output applications. These .025mm oversized bearings accommodate machined crankshaft journals, ensuring tight tolerances and reduced vibration for smoother operation across the RPM range. Built with ACL's F780 material for enhanced fatigue strength and corrosion resistance, they feature a 3/4 grooved design on select shells to direct oil efficiently to connecting rod bearings while maintaining full load-carrying surfaces on thrust positions. Ideal for rebuilds or performance upgrades on N63B44 and S63B44 engines, this set provides the dependable foundation needed for track days or daily driving, outperforming standard replacements through advanced metallurgy and exacting tolerances that hold up under boosted pressures and elevated temperatures.

What's Included in Your Purchase

  • Complete Main Bearing Set: 5 pairs of upper and lower bearings (10 shells total) covering all main journal positions (1-5), including thrust bearings at positions 2 and 4.
  • Part Number: 5M1573H-.025
  • UPC: 9315726470190
  • Oversize Specification: .025mm (0.001 inch) – Designed for crankshafts machined to 64.971–64.990mm shaft diameter and 70.000–70.019mm tunnel diameter.
  • Material: F780 tri-metal construction with polymer overlay for low-friction startup and high-load durability.
  • Bearing Dimensions:
    • Maximum Wall Thickness: 2.500mm
    • Maximum Length: 22.25mm (non-flanged shells)
  • Product Weight: 0.43 kg (0.95 lbs)
  • Shipping Details: Packaged in a compact box measuring 3 x 3 x 2 inches; total shipping weight 1 lb.

Vehicle Fitment

These bearings fit BMW models equipped with the N63B44 (4395cc V8 Twin Turbo, introduced 2008) or S63B44 (4395cc V8 Twin Turbo, introduced 2009) engines. Compatible with both original and TU (Technical Update) variants. Verify your engine code for exact match.

Year Range

Make

Model

Submodel/Notes

2008–2014

BMW

X6

xDrive50i (E71) – N63B44

2009–2015

BMW

7 Series

750i / 750Li (F01/F02) – N63B44

2009–2016

BMW

7 Series

750i xDrive (F02) – N63B44

2010–2013

BMW

5 Series Gran Turismo

550i (F07) – N63B44

2010–2017

BMW

5 Series

550i xDrive (F10) – N63B44

2011–2017

BMW

X5

xDrive50i (E70) – N63B44

2012–2018

BMW

6 Series

650i / 650i xDrive (F12/F13) – N63B44

2012–2018

BMW

6 Series Gran Coupe

650i xDrive (F06) – N63B44

2011–2016

BMW

M5

Base (F10) – S63B44

2012–2014

BMW

M6

Convertible / Coupe (F12/F13) – S63B44

2012–2014

BMW

M6 Gran Coupe

Base (F06) – S63B44

2014–2020

BMW

X5 M

Base (F85) – S63B44

2014–2019

BMW

X6 M

Base (F86) – S63B44

2017–2023

BMW

5 Series

M550i xDrive (G30) – N63B44TU

2018–2023

BMW

X7

xDrive50i (G07) – N63B44TU

This ACL set installs directly without modifications, supporting oil clearances from 0.001–0.003 inches for balanced lubrication in stock or modified setups. Pair with ACL rod bearings for a full bottom-end refresh.

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