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ACL engine bearing shells and retail packaging — representative product photo
ACL engine bearing-shell profile drawing — shell shape and oil-hole layout
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ACL Ford/Mazda 4 2.3L DOHC Duratec Standard Size High Performance Rod Bearing Set

ACL
ACL4B8170HX-STD
9315726165904
Bearings
Out of stock
$ 95.98

ACL 4B8170HX-STD is a connecting-rod bearing set for the cataloged Ford / Mazda Duratec 23, L3 MZR engine configurations. STD manufacturer size designation; verify the exact engine and assembled clearance.

Bearing Configuration

HX specifies 0.001 inch (0.025 mm) additional oil clearance relative to the corresponding H-STD set on the specified standard-size shaft. It is separate from any repair-size or housing-oversize designation.

ACL’s 2023 Mazda MZR guide separates this 2.3L L3 rod-bearing family from the L3-VDT DISI Turbo families 4B8171 without a notch and 4B8172 with a notch. A shared 5M8174 main-bearing family does not make those rod sets interchangeable.

Engine Application

Manufacturer / Engine Ford — Duratec 23
Manufacturer / Engine Mazda — L3 MZR

The engine-family list identifies catalog applications, not universal vehicle fitment. Confirm the exact engine version, crankshaft, rods, block and bearing location. Vehicle names and photos do not replace dimensional verification.

Specifications

Brand ACL
Manufacturer Part Number 4B8170HX-STD
Component Connecting-Rod Bearing Set
Size Selection STD manufacturer size designation; verify the exact engine and assembled clearance.
Catalog Rod Housing Bore (STD journal) 53.025–53.045 mm
Catalog Rod Journal Diameter (STD) 49.980–50.000 mm
Catalog Family ACL Race Series
Half Type Identical halves
Catalog Size Options STD

Quantity and Assembly Checks

Confirm the rod-bearing set contents and shell positions against the complete manufacturer number. The photo is representative of the part family.

Measure shaft journals, housing bores and assembled oil clearance using the engine builder’s specification. Check oil-hole alignment, groove placement and crankshaft fillet clearance before final assembly. Catalog standard dimensions must not be treated as the finished dimensions for a different repair size. ACL specifies that abrasive pads or paper must not be used on the bearing surface to alter oil clearance.

Frequently Asked Questions

Is the year and model enough to choose this bearing? No. Match 4B8170HX-STD to the exact engine and measured build specification.

What size is this listing? STD manufacturer size designation; verify the exact engine and assembled clearance.

Can I substitute a different suffix? Compare the complete grade, size, locating features and assembled clearance before substituting any bearing.

Related Engine Parts

ACL 5M8174HX-STD main bearings. This separate component uses its own measured main-journal clearance; confirm the exact engine configuration and size before pairing parts.

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