Perf. Piston Ring Set V8 4.040 Bore 1.5x1.5x3.0

The Perf. Piston Ring Set V8 4.040 Bore 1.5x1.5x3.0 from NPR Piston Rings is engineered for serious engine builders and performance enthusiasts undertaking V8 rebuilds, overbores, or high-performance modifications. This complete ring set addresses the critical role piston rings play in sealing combustion pressure, controlling oil consumption, and maintaining engine efficiency under demanding conditions. Whether you're restoring a stroker engine, upgrading a stock block, or preparing a race-ready powerplant, quality ring sets are non-negotiable components that directly impact compression, longevity, and power output.

This three-piece ring design—featuring 1.5mm top ring, 1.5mm second ring, and 3.0mm oil ring thicknesses—is sized specifically for 4.040-inch bore applications, ensuring precision fit and optimal sealing geometry. The individual ring dimensions are calibrated to manage peak firing pressures, minimize blowby, and regulate oil film thickness on cylinder walls across the full RPM range. NPR rings are manufactured with attention to material composition and radial tension, critical factors that determine how effectively rings maintain their sealing properties under thermal cycling and mechanical stress, especially in naturally aspirated or boosted engines running near their limits.

This piston ring set is ideal for V8 engine builders working with 4.040-inch bore diameters, including common overbore applications on small-block and big-block platforms. Installation requires proper ring end gap measurement, honing verification, and careful assembly technique to prevent ring breakage and ensure correct sealing from cold start through peak operating temperature. Compatibility is bore-specific; confirm your engine's current or target bore diameter before ordering to guarantee proper fit and performance—undersized or oversized rings will compromise compression and oil control, leading to blowby, excessive consumption, and accelerated wear.