Piston Ring 4.260FileFit Bore 1.0 1.0 2.0mm

The Piston Ring 4.260 File Fit Bore 1.0 1.0 2.0mm from MAHLE PISTONS is an OEM-quality replacement ring set engineered for precision engine rebuilds and high-performance modifications. This component is essential for any mechanic or engine builder restoring a classic or modern engine to factory specifications or preparing it for upgraded boost levels. File-fit rings require hand-fitting during installation, allowing you to achieve optimal ring gap clearance tailored to your specific bore diameter and engine's intended duty cycle.

The 4.260-inch bore specification denotes compatibility with mid-sized displacement engines commonly found in performance applications and restoration projects. The ring stack configuration—1.0mm, 1.0mm, and 2.0mm—represents the compression ring, second ring, and oil control ring thicknesses, respectively, a traditional geometry proven to balance blowby control, oil management, and durability across wide RPM ranges. MAHLE's manufacturing precision ensures minimal groove wear and consistent sealing geometry; the file-fit design eliminates the variability of pre-gapped rings, letting you dial in exact clearance for your engine's thermal expansion characteristics and intended operating temperature.

This ring set is ideal for enthusiasts rebuilding vintage muscle cars, street rods, or modern engines stepping up to forced induction where tight tolerances and optimized ring sealing directly impact power output and longevity. Installation requires a ring file, gap-setting fixture, and bore micrometer to achieve the correct end gaps—typically 0.003" to 0.005" per inch of bore diameter—making this product best suited for experienced engine builders or machine shops equipped for precision work. Compatibility is specific to 4.260-inch bore diameter pistons; confirm your piston part number and bore specification before purchase to ensure proper fit and function.