ACL 4B1956HX-STD Race Rod Bearing Set STD +0.001" Honda D15 D16 D16Y D16Z Civic

Vehicle Fitment

• 1988-2000 Honda Civic (EF/EG/EH/EJ/EK series) - D15B, D15Z, D16A, D16Y, D16Z series (1.5L/1.6L SOHC Inline-4)
• 1988-1991 Honda CRX (EF series) - D15B, D16A6 (1.5L/1.6L SOHC Inline-4)
• 1993-1997 Honda Del Sol (EG/EH series) - D15B, D16Z6, D16Y (1.5L/1.6L SOHC Inline-4)
• Also fits B18A (USA), B20B4, B20Z2 (Honda CR-V/Integra LS non-VTEC) where crankpin journal dimension matches
• JDM ZC SOHC and DOHC variants sharing D-series journal dimensions

Fitment Notes

• The HX designation indicates extra oil clearance: the bearing wall is approximately 0.013mm thinner per shell compared to the standard 4B1956H-STD set, providing approximately 0.025mm (0.001") of additional running clearance at standard crankshaft journal diameter - without any crankshaft grinding.
• Recommended for high-performance, high-RPM, or forced-induction D-series builds where slightly increased oil film thickness is desired for improved bearing protection under elevated loads and temperatures.
• For standard oil clearance at stock journal diameter, use 4B1956H-STD. For reground crankshafts, use the appropriate oversize H set: 4B1956H-.025 (+0.025mm) or 4B1956H-.25 (+0.25mm).
• Covers all D15B/D15Z and D16A/B/W/Y/Z engine code variants sharing the same crankpin journal diameter. Most common US-market applications: D16A6, D16Y5, D16Y7, D16Y8, and D16Z6.
• 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 high-RPM and forced-induction demands of built Honda D-series 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 under extreme load.
• Hardened steel backing on all rod bearings improves structural support of the bearing lining and maintains crush under high sustained loads and temperatures.
• High-strength overlay plate with reduced thickness provides improved fatigue resistance compared to OEM-spec bearings - critical in turbocharged D-series builds and high-revving naturally aspirated applications.
• 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 D-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 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: 4B1956HX-STD
• Product Line: ACL Race Series
• Application: Connecting Rod Bearings
• Engine Compatibility: Honda D15B/D15Z variants (1.5L SOHC); Honda D16A/D16B/D16W/D16Y/D16Z variants (1.6L SOHC); Honda ZC; B18A (USA), B20B4, B20Z2 (matching journal only)
• Crankshaft Size: Standard (STD - Unground)
• Oil Clearance Designation: HX - Extra +0.025mm (+0.001") clearance vs. H-STD
• Shaft (Crankpin) Diameter: 44.980-45.000mm (1.7709-1.7717 in)
• Tunnel (Housing Bore): 48.000-48.020mm (1.8898-1.8906 in)
• Maximum Wall Thickness at Crown: approx. 1.486mm (0.0585 in)
• Maximum Overall Length: 18.5mm (0.728 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 4B1956HX-STD connecting rod bearing set is the extra-clearance performance option for Honda's D-series inline-4 engine family - the 1.5L and 1.6L SOHC engines powering the Honda Civic, CRX, and Del Sol through multiple generations. Sharing the same standard crankpin journal diameter as the 4B1956H-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. This increased clearance supports a thicker hydrodynamic oil film - a meaningful advantage in turbocharged D16Y/Z applications or any build where a more liberal oil clearance specification is preferred at stock journal size.

Built on ACL's Race Series tri-metal platform, these bearings deliver superior fatigue resistance, bearing retention, and oil film stability compared to OEM Honda shells. A practical choice for boosted D-series builds where sustained elevated cylinder pressures and temperatures demand more from the bottom end. Always confirm actual running clearance at assembly. Sold as a complete set of 8 shells for one engine.