ACL 4B1972HD-STD Race Rod Bearing Set STD Dowel Honda K20A2 K24A RSX Civic Si

Vehicle Fitment

• 2002-2006 Acura RSX Type-S (K20A2, 2.0L DOHC 16v i-VTEC, 200 hp) - with aftermarket dowel-pin connecting rods
• 2002-2005 Honda Civic Si EP3 (K20A2, 2.0L DOHC 16v i-VTEC, 197 hp) - with aftermarket dowel-pin connecting rods
• 2003-2012 Honda Accord (K24A, 2.4L DOHC 16v i-VTEC) - with aftermarket dowel-pin connecting rods
• 2002-2014 Honda CR-V (K24A, 2.4L DOHC 16v i-VTEC) - with aftermarket dowel-pin connecting rods
• 2003-2011 Honda Element (K24A, 2.4L DOHC 16v i-VTEC) - with aftermarket dowel-pin connecting rods
• All K20A2 and K24A applications using aftermarket connecting rods equipped with a dowel-pin bearing locating hole

Fitment Notes

• The "D" designation is critical: this set includes a dowel hole in the lower bearing shell, designed for use with aftermarket connecting rods that use a dowel pin to locate and retain the bearing shell (e.g., Carrillo, Eagle, Brian Crower, Manley, and similar performance rod brands for K-series). Do NOT use in OEM Honda K-series connecting rods - factory rods use a tang/notch locator, not a dowel pin, and require the standard 4B1972H-STD (no dowel hole) instead.
• Standard (STD) crankshaft rod journal diameter - for use with stock or unworn crankpins at factory diameter only. For reground crankshafts, use 4B1972HD-.025 (+0.025mm) or 4B1972HD-.25 (+0.25mm).
• For the same dowel-hole configuration with extra oil clearance, use 4B1972HXD-STD.
• Always verify your connecting rod's bearing retention design before ordering. Using a dowel-hole bearing in a tang-style rod (or vice versa) can result in improper bearing seating and catastrophic engine failure.
• Always confirm actual running clearance with Plastigage or a dial bore gauge after assembly.
• Sold as a complete set of 8 bearing shells - sufficient for one full 4-cylinder engine build.

Features

• Tri-metal construction: copper-lead alloy lining bonded over a hardened steel backing, with a high-strength overlay plate - engineered for the high-RPM and high-boost demands of built K20A2 and K24A engines running performance aftermarket connecting rods.
• Dowel hole in lower bearing shell precisely machined to align with the dowel pin in compatible aftermarket connecting rods, ensuring correct bearing orientation and retention throughout engine operation.
• Hardened steel backing on all rod bearings improves structural support of the bearing lining and maintains crush under the high sustained loads expected in race and high-power K-series builds.
• High-strength overlay plate with reduced thickness provides improved fatigue resistance compared to OEM-spec bearings - critical for high-revving or forced-induction K-series builds at elevated power levels.
• Increased bearing crush and tighter wall tolerances ensure consistent, secure seating in the connecting rod housing bore, reducing the risk of bearing spin.
• Enlarged ID chamfers on bearing edges accommodate the larger fillet radii found on performance and aftermarket K-series crankshafts.
• 3/4-groove design optimizes oil supply to the rod journal and maximizes load-carrying surface area across the bearing face.
• Elimination of flash plating on bearing backs improves heat transfer and maximizes grip between the bearing shell and rod housing bore.
• Increased eccentricity compensates for bore distortion at high RPM and assists in the formation of a stable hydrodynamic oil film under load.

Specifications

• Part Number: 4B1972HD-STD
• Product Line: ACL Race Series
• Application: Connecting Rod Bearings - With Dowel Hole in Lower Shell
• Engine Compatibility: Honda/Acura K20A2 (1998cc DOHC 16v i-VTEC); Honda K24A (2354cc DOHC 16v i-VTEC)
• Rod Retention Type: Dowel Pin (aftermarket connecting rods only - NOT for OEM Honda K-series rods)
• Crankshaft Size: Standard (STD - Unground)
• Shaft (Crankpin) Diameter: 47.980-48.000mm (1.8890-1.8898 in)
• Tunnel (Housing Bore): 51.004-51.024mm (2.0080-2.0088 in)
• Maximum Wall Thickness at Crown: approx. 1.501mm (0.0591 in)
• Bearing Material: Tri-Metal Copper-Lead Alloy / Hardened Steel Backing
• Quantity: Set of 8 Shells (complete engine set)

Included Components

• 8x Race Series Connecting Rod Bearing Shells - Standard Size, With Dowel Hole in Lower Shell

Product Description

The ACL Race Series 4B1972HD-STD connecting rod bearing set is the standard-size, dowel-hole version for Honda/Acura K20A2 and K24A engines running aftermarket connecting rods. The "D" suffix designates a dowel hole machined into each lower bearing shell, designed to accept the locating dowel pin found in most premium aftermarket K-series connecting rods from brands such as Carrillo, Eagle, Brian Crower, Manley, and others. This design provides positive bearing orientation and retention in high-performance rod bores where a tang locator is replaced by a dowel pin system. It is not compatible with OEM Honda K-series factory connecting rods, which use a notch/tang retention system and require the standard 4B1972H-STD instead.

Built on ACL's proven Race Series tri-metal platform, these bearings deliver superior fatigue resistance, bearing retention, and oil film stability over OEM shells - an essential pairing with any aftermarket K-series rod set in a high-power build. Always verify connecting rod bearing retention type before ordering. Sold as a complete set of 8 shells for one engine.