MAHLE 42257CP.030 Premium Plasma-Moly Engine Piston Ring Set Over - 0.030

The MAHLE 42257CP.030 is a premium-grade engine piston ring set engineered for 0.030-inch overbore applications. As part of MAHLE's renowned CP-series lineup, this ring set is built to OE form, fit, and function standards, delivering the reliability and precision that professional engine builders demand.

Key Features:

• Plasma-Moly Top Ring: The upper compression ring features a barrel-faced contact area with a plasma-moly facing for superior scuff resistance, reduced break-in time, and long-term durability
• CNC-Controlled Gap Chamfer: Precision machined ring gaps optimize compression sealing and minimize blowby
• Reverse-Twist Intermediate Ring: The second ring uses a reverse-twist design combined with taper-race machining for enhanced groove side sealing and improved contact with the cylinder wall
• CP-20 Oil Ring Assembly: Features an exclusive 20-degree ear angle for maximum side sealing against the cylinder wall, plus a chemically polished expander for superior oil drainback
• Pre-Lapped for Instant Seating: Rings are pre-lapped at the factory, virtually eliminating break-in time and allowing the engine to achieve full performance immediately
• Optimized Ring Tension: Ring materials, coatings, and tension are precisely calibrated per application to reduce friction and extend service life
• OE-Driven Engineering: Designed to meet OE requirements, reducing friction and ring mass while minimizing engine oil consumption

MAHLE is one of the world's largest OE piston ring manufacturers, supplying original equipment to major automakers globally. The 42257CP.030 ring set reflects that same engineering excellence in an aftermarket package, making it the preferred choice for engine rebuilders seeking a reliable, installer-friendly solution.