Single Cyl Piston Pack 4.065 Bore

The MAHLE PISTONS Single Cylinder Piston Pack 4.065 Bore (Part No. 4065MS-112-1) is a precision performance piston ring set engineered for high-performance and racing applications. This file-fit piston ring pack delivers controlled ring tension and thermal management essential for competitive engines and demanding power delivery environments where engine durability and consistent compression must be maintained under extreme operating conditions.

Specifically configured for 4.065-inch bore cylinders, this eight-cylinder ring set features 1.0 x 1.0 x 2.0 mm ring dimensions with standard tension design and steel construction rated to HV385 hardness specifications. The thermal treatment and material composition enable reliable sealing across wide temperature ranges while minimizing blowby and oil consumption—critical factors in performance engines operating at high RPM or extended throttle. File-fit installation requires precision honing to exact bore specifications, ensuring optimal ring-to-wall contact and sealing efficiency.

This pack serves engine builders, performance shops, and motorsport competitors rebuilding eight-cylinder engines for road racing, drag racing, and high-output street applications. MAHLE's performance-grade piston rings are preferred in applications where factory tolerances are insufficient—particularly when maximum compression ratio, boost response, and long-term reliability under sustained load matter. The precise bore diameter and hardness specification minimize ring wear while maintaining zero-compromise sealing over multiple race seasons or extended service intervals.

File-fit piston ring sets demand careful installation and proper bore preparation—they are not drop-in replacements for stock engines. Verify your bore diameter, honing finish, and installation clearances before purchase. MAHLE is recognized as an OEM component supplier to major engine manufacturers, making this performance series ring pack a trusted choice for serious engine rebuilds.