ACL Bearings 4B1171H-.25 Race Series Rod Bearing Set 0.25mm Undersize

The ACL Bearings 4B1171H-.25 is a high-performance Race Series connecting rod bearing set designed for Nissan L-Series (1967-86), Z-Series (1978-88), and FJ20E/FJ20-ET engines. This precision-engineered bearing set is manufactured in 0.25mm (0.010") undersize for crankshaft journals that have been reground or machined, allowing proper oil clearance on rebuilt performance engines.

Key Features:

• Tri-metal construction with high-strength overlay plate for superior fatigue resistance
• Hardened steel backs improve bearing lining support and retention in the housing
• Increased crush for improved bearing retention under high-RPM conditions
• Flash plating eliminated from bearing backs to maximize heat transfer and housing grip
• Increased eccentricity to compensate for bore distortion at high RPM
• Tight wall tolerances help maintain consistent oil clearances
• Engineered to withstand extreme racing conditions and high RPM operation

Specifications:

• Bearing Width: 0.87 inches (22.1mm)
• Outside Diameter: 2.0868-2.0871 inches (53.005-53.013mm)
• Shaft Diameter Range: 1.967-1.9675 inches (49.962-49.975mm)
• Maximum Wall Thickness: 0.0592 inches (1.504mm)

ACL Race Series bearings are trusted by champions worldwide and are the choice for record-setting engines from sport compact to small block race machines. The unique combination of design, metallurgy, and precision manufacturing delivers unmatched durability and performance under extreme conditions.