Carrillo CPN-3957 CPN Piston Ring Set High-Performance Gas-Nitrided Steel

The Carrillo CPN-3957 is a high-performance CPN-series piston ring set engineered by CP-Carrillo for sport compact and small-bore engine applications operating under intense cylinder pressures. Designed as a direct companion to CP-Carrillo CPN and CPN2 pistons, this ring set delivers superior sealing, reduced friction, and long-term durability in both naturally aspirated and forced induction environments.

Ring Package Specifications:

• Top Ring: 1.0mm gas-nitrided steel — provides robust combustion sealing and exceptional resistance to wear, outperforming wider 1.5mm and 1/16" conventional top rings in friction reduction
• Second Ring: 1.2mm Napier-style (hooked face) design — improves oil scraping and control over standard taper-faced second rings
• Oil Ring: 2.8mm flex vent oil ring — delivers optimal sealing power with minimal drag

Key Features:

• Compatible with advanced cylinder bore coatings including Nikasil, making them suitable for modern high-performance engine builds
• Sold as a set per piston for precise, application-matched installation
• Engineered for high cylinder pressure environments including turbocharged and high-compression applications
• Designed to be used with plateau honing and a cylinder bore cross-hatch angle of 35–40 degrees for optimal ring seating

CP-Carrillo CPN ring sets are the preferred choice for engine builders demanding precision-engineered components that can withstand the rigors of competition and high-output street performance. Made in the USA by one of the most trusted names in forged piston and ring technology.