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Engines and Components› Engine Bearings

ACL

Performance Rod Bearings for Mazda L3-VDT Engines

$135.18 $71.99 Save $63.19

SKU: 4B8172H

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$100 Minimum Order
Non-Returnable Item
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The ACL 4B8172H is a set of high-performance rod bearings designed for Mazda L3-VDT engines. These bearings feature a multiple-layer construction for high strength and seizure resistance, with no flash plating to improve bearing retention and heat transfer. They also offer improved retention through higher radial contact pressure.

The bearings include increased eccentricity to better adapt to bore distortion during high-speed operation. The design incorporates full 180° grooved uppers and matching partial grooves in the lowers to reduce interruptions in big-end oil supply, along with tapered groove run-out to smooth oil cut-off and prevent pressure pulsing and cavitation.
Show original supplier description
The ACL 4B8172H is a set of high-performance rod bearings engineered for motorsport applications, recognized as a premier component in championship-winning race engines. These bearings are manufactured to exacting tolerances, ensuring consistent accuracy in wall thickness and crush for reliable fit and maintained clearances. Featuring a multiple-layer construction, these bearings provide a blend of characteristics that offer high strength and excellent seizure resistance. Unlike some bearings, no flash plating is applied, which further improves bearing retention and maximizes heat transfer. Improved retention is also achieved through higher radial contact pressure, which effectively locks the bearing into the housing. The design incorporates increased eccentricity to enhance shape adaptation and compensate for bore distortion that can occur during high-speed operation. The upper bearings feature a full 180° groove, complemented by a partial groove in the lower bearings. Additionally, the tapered groove run-out smooths the big-end supply cut-off, helping to avoid pressure pulsing and cavitation. These rod bearings are specifically designed for Mazda L3-VDT engines, fitting the 2007-2012 Mazda Mazdaspeed3, 2006-2007 Mazda Mazdaspeed6, and 2006-2012 Mazda CX-7. The package includes one full set of rod bearings.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

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Specifications

BrandACL
Part Number4B8172H
CategoryEngines and Components
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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