ACL Race Series Connecting Rod Bearing Set – .25mm Undersize

Part #: 4B8172H-.25

Overview

The ACL 4B8172H-.25 Race Series Connecting Rod Bearing Set is designed for select Ford 2.0L and 2.3L EcoBoost engines and the Mazda 2.3L MZR DISI Turbo. This version is sized for crankshafts requiring 0.25mm (0.010") undersize bearings and uses ACL's Race Series tri-metal construction for increased durability in performance and high-load engine applications.

Key Features

• Fits select Ford 2.0L EcoBoost engines
• Fits select Ford 2.3L EcoBoost engines
• Fits Mazda 2.3L MZR DISI Turbo / L3-VDT
• 0.25mm (0.010") undersize
• Complete set for 4 connecting rods
• ACL Race Series performance construction
• Tri-metal bearing material
• Hardened steel backing
• Identical upper and lower bearing halves
• Precision manufactured for consistent bearing clearances
• Designed for performance, high-RPM, and high-load engine builds

Construction & Design

ACL Race Series bearings combine tri-metal construction with hardened steel backing and performance-focused bearing geometry. The 4B8172H series uses identical bearing halves and is engineered to provide the strength and dimensional consistency required for modified and performance engines.

Installation & Fitment

Engine Families: Ford EcoBoost / Mazda MZR
Engine Sizes: 2.0L / 2.3L Turbo
Bearing Type: Connecting Rod
Series: ACL Race Series
Size: 0.25mm (0.010") Undersize
Material: Race Series Tri-Metal
Quantity: Set for 4 Connecting Rods
Standard Shaft Diameter: 2.0465"–2.0472"
Housing Bore: 2.1662"–2.1667"
Maximum Wall Thickness: 0.0591"
Maximum Width: 0.669"

Note: These are not standard-size bearings. They are intended for an appropriately machined crankshaft requiring 0.25mm (0.010") undersize connecting rod bearings.

What's Included

• 4 upper connecting rod bearing halves
• 4 lower connecting rod bearing halves
• Complete bearing set for all 4 connecting rods

Ideal For

Ideal for Ford 2.0L/2.3L EcoBoost and Mazda 2.3L MZR performance rebuilds requiring a 0.25mm (0.010") undersize ACL Race Series connecting rod bearing set.