Carrillo RS1110-3917 CPP Piston Ring Set 3.917 Bore File-Fit

The Carrillo RS1110-3917 is a CP-Carrillo CPP piston ring set engineered for high-performance and racing engines running a 3.917-inch bore diameter. Designed as a direct companion to CP-Carrillo forged pistons, this file-fit ring set delivers the precise sealing, oil control, and durability demanded by forced induction, nitrous, and naturally aspirated race applications.

Key Features:

• Gas nitrided steel top ring — provides exceptional hardness and reduced friction for long service life in high-stress environments
• Napier-style taper hook groove (THG) second ring — acts as a wiper ring, pushing oil away from the combustion chamber and improving oil control over conventional taper-faced designs
• Low-tension flex-vent 3.0mm oil ring — optimizes oil management while minimizing parasitic drag
• File-fit design — allows the builder to achieve precise ring end gap for the specific application, whether naturally aspirated, turbocharged, supercharged, or nitrous-assisted
• 1 cylinder set — includes top compression ring, second ring, and oil ring assembly for one bore
• Engineered to work exclusively with CP-Carrillo CPP/CP piston ring grooves; OEM rings are not compatible

Proper cylinder preparation is essential for maximum ring seal. CP-Carrillo recommends plateau honing with a 35–40 degree cross-hatch angle and verifying bore roundness to within 0.0002 inches before installation. Always confirm ring end gap before assembly — failure to do so can result in severe engine damage. This ring set is manufactured in the USA to the exacting tolerances that CP-Carrillo is known for across automotive, powersports, and racing applications.