ACL 4B1912H-.025 Race Series Rod Bearings for Honda S2000/Prelude F20C/F22C/H22A

Vehicle Fitment

• 2000-2003 Honda S2000 AP1 (2.0L F20C I4; RWD)
• 2004-2009 Honda S2000 AP2 (2.2L F22C1 I4; RWD)
• 1997-2001 Honda Prelude (2.2L H22A4 I4 VTEC; FWD)
• Honda Prelude and Accord equipped with 2.2L H22A or H22Z I4 (non-US market variants including Accord Type R and Prelude 2.2 VTi; FWD)

Fitment Notes

• ACL catalogs H22 applications by engine code rather than chassis year - confirm your engine code before ordering
• Connecting rod (big end) bearings only - main bearings are a separate set (5M1913H for F20C/F22C, 5M1957H for H22)
• .025 size is a clearance-tuning option, not a replacement for a reground crankshaft
• Journals must be measured and clearance verified during assembly

Features

• Trimetal construction combining lead, tin, copper, and nickel for strength and seizure resistance
• Hardened steel backing supports the bearing lining and improves retention in the rod housing
• High-strength overlay plate with reduced thickness for improved fatigue life
• Increased crush height for better retention under high radial contact pressure
• Flash plating eliminated from the bearing back to maximize heat transfer and housing grip
• Increased eccentricity compensates for bore distortion at high RPM
• Micron-tolerance machining delivers consistent wall thickness across the set
• Engineered for sustained high-RPM and elevated cylinder pressure applications

Specifications

• Series: ACL Race Series (H-series suffix)
• Position: Connecting rod, big end (upper and lower shells)
• Size: .025 (0.025 mm)
• Clearance effect: Bearing wall 0.025 mm thicker than STD, reducing diametral oil clearance by approximately 0.001 in on a standard-diameter journal
• Alternate use: Suits a crank journal ground 0.025 mm undersize
• Material: Trimetal (steel back, copper-lead-tin alloy, overlay)
• Back plating: None (flash plating deleted)
• Set coverage: 4-cylinder, 4 rod journals

Included Components

• 8x Connecting Rod Bearing Shells (4 upper, 4 lower)

Product Description

ACL Race Series rod bearings are the standard replacement when a Honda F20C, F22C, or H22 is being built past its factory power and RPM limits. The Trimetal construction and hardened steel backing handle the radial loads that flatten stock bearings, while the deleted back plating improves heat transfer out of the shell - the failure mode that usually shows up first in a high-RPM four. Increased eccentricity helps maintain a hydrodynamic oil film as the rod bore distorts under load.

This is the .025 size, meaning each shell is 0.025 mm thicker than standard. On a standard-diameter journal it tightens diametral oil clearance by roughly 0.001 inch, which is how most builders dial in clearance when a STD set measures loose but the crank is still within spec. It also works as the correct size for a journal ground 0.025 mm under. Either way, plastigauge or a bore gauge and micrometer should confirm actual clearance during assembly rather than assuming the size on the box gets you there.