ACL (4M2505H-STD) Standard Size High Performance Main Bearing Set for Nissan

ACL Race Series performance engine bearings are manufactured to exacting tolerances. Micron tolerance machining supported by precision measurement systems delivers consistent accuracy to key characteristics like wall thickness and crush. This ensures reliable fit and helps maintain consistent clearances. A blend of characteristics to provide high strength and excellent seizure resistance. No flash plating is applied to further improve bearing retention an maximize heat transfer.

• High Strength Steel Backing, Higher tensile strength of steel alloy improves rod bearing strength and retention. Increased crush improves bearing retention from higher radial contact pressures, and also improves heat dissipation.
• Increased Eccentricity, Bearing eccentricity is the gradual reduction in wall thickness between the crown and parting line. This enhanced engineering feature allows for compensation for bore distortion and assists in the formation of hydrodynamic oil film.
• Extended Oil Grooves and Tapered Groove Run-Out, Main bearing grooved uppers with matching groove lowers provide for less interruption to big end oil supply. Tapered groove run–out smooths big end supply cutoff and avoids pressure pulsing and cavitation.
• ACL Race Series Main Bearings