ACL 4B1912HX-STD Race Rod Bearing Set STD +0.001" Honda F20C F22C H22A S2000

Vehicle Fitment

• 2000-2005 Honda S2000 AP1 (F20C1/F20C2, 2.0L DOHC 16v VTEC, 237-247 hp)
• 2004-2009 Honda S2000 AP2 (F22C1, 2.2L DOHC 16v VTEC, 239 hp)
• 1991-1996 Honda Prelude IV (BB1/BB3/BB4) - H22A1, H22A2 (2.2L DOHC 16v VTEC)
• 1997-2001 Honda Prelude V (BB5/BB6/BB7/BB8) - H22A2, H22A4, H22A5, H22A8, H22Z1 (2.2L DOHC 16v VTEC)
• 1997-2002 Honda Accord VI Type-R - H22A7 (2.2L DOHC 16v VTEC)

Fitment Notes

• The HX designation indicates extra oil clearance: the bearing wall is approximately 0.013mm thinner per shell compared to the standard 4B1912H-STD set, providing approximately 0.025mm (0.001") of additional running clearance at standard crankshaft journal diameter - without any crankshaft grinding.
• Particularly well-suited to the F20C and F22C engines given their extreme RPM range - a slightly more liberal oil clearance supports a thicker hydrodynamic oil film at the sustained high-RPM conditions these engines routinely see near redline.
• For standard oil clearance at stock journal diameter, use 4B1912H-STD. For reground crankshafts, use the appropriate oversize H set: 4B1912H-.025 (+0.025mm) or 4B1912H-.25 (+0.25mm).
• The F20C/F22C and H22A/H22Z engine families share identical crankpin journal dimensions - this HX set fits all listed variants at standard crankshaft size.
• Always confirm actual running clearance with Plastigage or a dial bore gauge after assembly - do not rely solely on bearing size designation.
• 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 extreme high-RPM demands of the F20C (9,000 rpm redline) and H22A VTEC engines.
• HX extra-clearance wall thickness provides approximately 0.025mm (0.001") of additional oil clearance versus the H-STD set, increasing oil film volume between the crankpin and bearing surface for improved lubrication at sustained high RPM.
• Hardened steel backing on all rod bearings improves structural support of the bearing lining and maintains crush under the sustained high-RPM loads characteristic of naturally aspirated Honda performance engines.
• High-strength overlay plate with reduced thickness provides improved fatigue resistance compared to OEM-spec bearings - critical in high-revving S2000 and Prelude builds at or above the factory power ceiling.
• 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 Honda 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 the 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: 4B1912HX-STD
• Product Line: ACL Race Series
• Application: Connecting Rod Bearings
• Engine Compatibility: Honda F20C1, F20C2 (1997cc); Honda F22C1 (2157cc); Honda H22A1, H22A2, H22A4, H22A5, H22A7, H22A8, H22Z1 (2157cc)
• Crankshaft Size: Standard (STD - Unground)
• Oil Clearance Designation: HX - Extra +0.025mm (+0.001") clearance vs. H-STD
• 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. 1.483mm (0.0584 in)
• Maximum Overall Length: 19.4mm (0.764 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, Extra Oil Clearance (HX)

Product Description

The ACL Race Series 4B1912HX-STD connecting rod bearing set is the extra-clearance performance option for the Honda F20C, F22C, and H22A/H22Z DOHC VTEC inline-4 engine family - the engines powering the Honda S2000 AP1 and AP2 (2000-2009), Prelude IV and V (1991-2001), and Accord Type-R. Sharing the same standard crankpin journal diameter as the 4B1912H-STD, the HX variant uses a slightly thinner wall (~0.013mm per shell) to deliver approximately 0.025mm (0.001") of additional running oil clearance without any crankshaft modification.

The HX variant is a particularly popular choice for F20C and F22C builds given the engine's extreme RPM range - the additional oil clearance supports a thicker hydrodynamic film at the sustained high-RPM conditions near the 9,000 rpm redline where bearing loads are at their most demanding. The F20C/F22C and H22A/H22Z families share identical crankpin journal dimensions, so this single HX set covers all listed applications. Built on ACL's Race Series tri-metal platform with superior fatigue resistance and oil film stability over OEM shells. Always confirm actual running clearance at assembly. Sold as a complete set of 8 shells for one engine.