Perf. Piston Ring Set V8 4.040 Bore 1.2x1.5x3.0

The NPR Performance Piston Ring Set V8 4.040 Bore 1.2x1.5x3.0 is purpose-built for serious engine builders and mechanics restoring or modifying high-displacement V8 powerplants. This eight-cylinder ring kit addresses a critical need: maintaining proper compression sealing and blow-by control in large-bore engines where factory ring sets may no longer exist or prove inadequate. Whether you're rebuilding a classic muscle car engine, upgrading a performance platform, or replacing worn compression rings in a street or competition build, this ring set delivers the seal integrity your engine demands.

Engineered from hardened nitride-coated steel, the Perf. Piston Ring Set features a 1.2 mm top ring, 1.5 mm second ring, and 3.0 mm oil control ring—a time-proven geometry optimized for V8 combustion dynamics and thermal cycling. The 4.040-inch bore specification targets mid-to-large displacement stroker builds and classic big-blocks, where precision ring fit is essential to prevent gas blowdown and oil consumption. Standard tension characteristics ensure balanced friction against cylinder walls while maintaining reliable sealing without excessive drag—critical for fuel economy and engine longevity. The nitride coating provides enhanced wear resistance and reduced friction, extending ring and cylinder wall life under sustained RPM and load conditions typical of performance driving.

This ring set suits engine builders modernizing vintage platforms, enthusiasts performing complete overhauls on street or track engines, and mechanics stocking inventory for customer rebuilds. Proper installation requires careful honing of cylinder walls to specified finish (typically 20–40 microinches Ra), precise ring gap filing to match your specific block and ring set, and exact positioning during assembly. The kit comes complete for a single V8 engine; verify your exact bore diameter and piston specifications before purchase to ensure proper fit and optimal sealing performance across all eight cylinders.