ACL 4B1972H-STD Honda/Acura K20/K24 Rod Bearings

4B1972H-STD Race Series Rod Bearings for Honda and Acura K20/K24 Engines

ACL 4B1972H-STD is a standard-size Race Series connecting rod bearing set cataloged for selected Honda and Acura K20 and K24 engines. Confirm the exact engine code, crankshaft version, journal dimensions, bearing position, and assembled clearances before ordering.

Key Features

• Race Series trimetal construction for high-load performance builds
• Cataloged for K20A2, K20Z1, K24A, K24Z1, and K20C1 engine families
• Standard-size H-series configuration
• Hardened steel backs and application-specific shell geometry
• ACL 4B1972H-STD must be selected by exact engine and measured dimensions

Fitment

Vehicle year and model alone do not confirm compatibility. Engine swaps, mixed blocks and crankshafts, and previously machined assemblies require direct dimensional verification.

Specifications

Whats Included

• One ACL Race Series connecting rod bearing set
• Manufacturer packaging and identification for ACL 4B1972H-STD
• Only the component identified in this listing is included unless the package contents state otherwise

About ACL

ACL manufactures precision engine bearings for performance street, racing, and professional engine-building applications. Correct machining, clean assembly, proper fastener loading, and measured clearances are essential to bearing life.

Related Parts

Pair components only after confirming the exact ACL catalog application:

• ACL 5M1959H-STD main bearings
• ACL 1T1957-STD thrust washers

Frequently Asked Questions

What is the 4B1972H-STD?

It is an ACL connecting rod bearing set for the cataloged Honda and Acura engine applications shown above.

Does vehicle year and model confirm fitment?

No. Verify the engine code, crankshaft, journal dimensions, and bearing position.

Must clearances be measured?

Yes. A qualified engine builder should measure every relevant journal, housing bore, and assembled clearance.

Can I substitute another size suffix?

No. Standard, repair-size, and extra-clearance suffixes identify different dimensional requirements.

Are the related bearings included?

No. Main bearings, rod bearings, and thrust washers are separate components unless the listing explicitly states otherwise.

Does one bearing family fit every K-series engine?

No. For example, some K20C applications use a different main-bearing family even when a rod-bearing family is shared.

Can this rod set be paired with the same main bearings on every listed engine?

No. Main-bearing selection differs by engine code, especially for K20C applications.

Should a professional install these parts?

Yes. Precision engine-bearing installation should be completed or checked by an experienced engine builder.

Installation Instructions

1. Confirm ACL 4B1972H-STD against the engine build sheet and measured requirements.
2. Verify the engine code, block, crankshaft, and bearing positions.
3. Measure journals and housing bores with calibrated tools.
4. Clean all mating surfaces, oil passages, and bearing components.
5. Check locating features, oil-hole alignment, fillet clearance, and component orientation.
6. Install and torque fasteners using the engine builders specified sequence and procedure.
7. Measure assembled clearances, endplay where applicable, and free rotation. ACL specifies that abrasive pads or paper must not be used on the bearing surface to alter oil clearance.
8. Apply approved assembly lubricant and prime the oiling system before startup.