ACL Bearings 4B1647A-.25 Connecting Rod Bearing Set Undersize - 25mm

The ACL Bearings 4B1647A-.25 Standard Connecting Rod Bearing Set delivers race-tested durability and precision engineering for high-performance engine builds. Featuring a trimetal design with a high-strength overlay plate and reduced thickness for improved fatigue resistance, these bearings are backed by hardened steel for enhanced support and retention under extreme conditions.

Key Features:

• High-strength overlay plate with reduced thickness for improved fatigue properties and hardened steel backs on all rod bearings to improve support and bearing retention
• Elimination of flash plating on the back of the bearings to improve heat transfer and maximize grip between the bearings and housing
• Increased eccentricity to compensate for bore distortion at high RPM and assist in the formation of hydrodynamic oil films
• Tight consistent wall tolerances to help maintain consistent clearances
• Enlarged ID chamfers on bearing edges where required to accommodate large fillet radius on performance crankshafts

The .25mm (0.010") undersize specification provides precise fitment for engines where the crankshaft journals have been machined during rebuilds. ACL Race Series performance engine bearings are recognized as a premier brand throughout the motorsports world, with a unique combination of design, metallurgy and engineering that provides the endurance and capability to perform where others cannot.