ACL 8B1578H-.25 High-Performance Rod Bearing Set for BMW N63/S63 V8

BMW N63B44 4.4L 4395cc V8 Connecting Rod Set - .25mm (0.010") undersize

The ACL 8B1578H-.25 High-Performance Rod Bearing Set is designed for BMW N63 and S63 4.4L V8 engines requiring connecting rod bearings with a .25 mm, or .010-inch, undersize specification. Manufactured for performance-oriented and rebuild applications, this bearing set supports precise crankshaft-to-connecting-rod clearance when used with a properly machined crankshaft.

ACL high-performance rod bearings are engineered with advanced bearing materials and surface treatments to provide dependable load support, wear resistance, and oil retention under demanding engine conditions. The set is intended for professional engine rebuilding, performance upgrades, and replacement applications where accurate bearing fitment is essential. Always verify crankshaft journal measurements, bearing clearance, and engine specifications before installation.

This set fits select BMW M6 and X5 applications equipped with compatible N63 or S63 V8 engines, including model years from 2012 through 2018. Fitment can vary by engine code, production date, and crankshaft specification, so confirm the original bearing designation and required undersize before ordering. The ACL part number 8B1578H-.25 identifies the applicable high-performance rod bearing configuration for this application.

Brief Description: High-performance connecting rod bearing set for BMW N63/S63 4.4L V8 engines with .25 mm (.010-inch) undersize bearings.

Key Product Specifications & Technical Data:

• Brand: ACL
• Part Number: 8B1578H-.25
• Application: BMW N63/S63 V8 engines
• Engine Displacement: 4.4L, 4,395 cc
• Bearing Type: Connecting rod bearing set
• Bearing Size: .25 mm (.010-inch) undersize
• Performance Level: High performance
• Installation Requirement: Requires crankshaft journal and clearance verification

What's Included: One ACL connecting rod bearing set.

Fitment: Select 2012–2018 BMW M6 models and 2015–2017 BMW X5 models with compatible N63 or S63 V8 engine configurations.

Features:

• High-performance ACL connecting rod bearing set for BMW N63/S63 4.4L V8 engines
• .25 mm (.010-inch) undersize specification for crankshafts machined to the matching journal size
• Engineered bearing construction supports load capacity, wear resistance, and reliable oil control
• Suitable for professional engine rebuilds, performance applications, and replacement installations

Fitments:
2011 BMW X6 xDrive50i
2012 BMW M6 Base
2012 BMW X6 xDrive50i
2013 BMW 550i Gt Base
2013 BMW 650i Base
2013 BMW 750Li Base
2013 BMW M6 Base
2013 BMW X5 xDrive50i
2013 BMW X6 xDrive50i
2014 BMW 550i Base
2014 BMW 550i Gt Base
2014 BMW 650i Base
2014 BMW 750Li Base
2014 BMW M6 Base
2014 BMW X5 xDrive50i
2014 BMW X6 xDrive50i
2015 BMW 550i Base
2015 BMW 550i Gt Base
2015 BMW 650i Base
2015 BMW 750Li Base
2015 BMW M6 Base
2015 BMW X5 xDrive50i
2016 BMW 550i Base
2016 BMW 650i Base
2016 BMW M6 Base
2016 BMW X5 xDrive50i
2017 BMW 650i Base
2017 BMW M6 Base
2017 BMW X5 xDrive50i
2018 BMW 650i Base
2018 BMW M6 Base
2018 BMW X5 xDrive50i

Air Freight Prohibited: false
Not Carb Approved: false
Ltl Freight Required: false
Prop 65: Unknown
Part Type: automotive
Epa: N/A
Carb Acknowledgement Required: false
Regular Stock: t
Units Per Sku: 1