ACL 4B1925H-.25 Race Rod Bearing Set +0.25mm Honda B18C1 B18C5 Integra GSR ITR

Vehicle Fitment

• 1994-2001 Acura Integra GS-R DC2/DB8 (B18C1, 1.8L DOHC 16v VTEC, 170 hp - USDM)
• 1997-2001 Acura Integra Type R DC2 (B18C5, 1.8L DOHC 16v VTEC, 195 hp - USDM/CDM)
• 1995-2001 Honda Integra Type R DC2/DB8 (JDM B18C Spec R / B18C3, 1.8L DOHC 16v VTEC, 200 hp)
• 1994-2001 Honda Integra VTi-R (B18C2, 1.8L DOHC 16v VTEC - Australia/New Zealand)
• 1999-2001 Honda Integra Type R (B18C7, 1.8L DOHC 16v VTEC - Australia)

Fitment Notes

• The .25 suffix designates this as the +0.25mm oversize bearing set - intended for use when the crankshaft rod journals have been ground 0.25mm undersize during a rebuild. The thicker wall restores correct running oil clearance on a more significantly reground crankshaft.
• Do NOT use on a stock, unground crankshaft. For standard journal diameter, use 4B1925H-STD. For crankpins ground only 0.025mm undersize, use 4B1925H-.025.
• Always measure crankshaft rod journal diameter with a micrometer before selecting bearing size. Confirm actual 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, VTEC demands of built B18C applications in both naturally aspirated and forced-induction configurations.
• 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 boosted or high-revving B18C builds operating above factory 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 B18C 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: 4B1925H-.25
• Product Line: ACL Race Series
• Application: Connecting Rod Bearings
• Engine Compatibility: Honda/Acura B18C1, B18C2, B18C3 (JDM), B18C5, B18C7 - 1.8L DOHC 16v VTEC Inline-4 (1797cc)
• Crankshaft Size: +0.25mm Oversize (for crankpins ground 0.25mm undersize)
• Shaft (Crankpin) Diameter: 44.726-44.750mm (1.7608-1.7618 in)
• Tunnel (Housing Bore): 48.000-48.024mm (1.8898-1.8907 in)
• Maximum Wall Thickness at Crown: approx. 1.627mm (0.0641 in)
• Maximum Overall Length: 17.5mm (0.689 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 - +0.25mm Oversize

Product Description

The ACL Race Series 4B1925H-.25 connecting rod bearing set is the +0.25mm oversize option for the Honda/Acura B18C VTEC inline-4 engine family - the 1.8L DOHC 16v VTEC engine powering the Acura Integra GS-R (B18C1), Acura Integra Type R (B18C5), and the legendary Honda Integra Type R DC2 (JDM B18C/B18C3), among other regional variants. This oversize set is selected when the crankshaft rod journals have been ground 0.25mm undersize to address more significant surface wear, scoring, or out-of-round conditions discovered during inspection, restoring correct oil clearance on the reground crank.

The B18C family - particularly the B18C5 and JDM Type R spec - is one of the most frequently rebuilt high-performance Honda four-cylinder engines. ACL Race Series bearings deliver superior fatigue resistance, oil film stability, and bearing retention compared to OEM Honda shells, making them a standard upgrade in any serious B18C rebuild at any power level. Always verify crankshaft journal diameter with precision measurement and confirm clearances at assembly before final torque. Sold as a complete set of 8 shells for one engine.