MAHLE 42001CP.040 Original Engine Piston Ring Set Oversize - 0.040

The MAHLE 42001CP.040 is a premium OE-replacement engine piston ring set engineered to restore proper compression, minimize oil consumption, and extend engine service life. Featuring a 0.040" oversize bore, this set is ideal for engines that have been bored out during a rebuild. MAHLE is one of the world's largest OE piston ring manufacturers, and this set reflects the same engineering standards found in original equipment applications.

Key Features:

• SAE 9254 High-Alloy Steel Base Material — delivers higher tensile and yield strength, extended fatigue resistance, and increased material hardness for long-lasting performance
• Pre-Lapped Rings — seat immediately upon installation, virtually eliminating traditional break-in time
• Barrel-Faced Compression Rings — provide more efficient compression and include a CNC-controlled gap chamfer to minimize blow-by
• Napier Second Rings — high-quality grey iron/ductile iron BT and RBT design for superior oil control, improved combustion gas management, top ring stability, and reduced power loss
• Reverse-Twist Intermediate Rings — engineered with taper race machining for improved groove side sealing and enhanced cylinder wall contact
• CP-20 Oil Ring Assemblies — feature an exclusive 20-degree ear angle for optimum side sealing in the piston oil ring groove, plus a special chemical polish on the expander for improved oil drain back
• Optimized Ring Tension and Coatings — materials and coatings are application-specific to reduce friction and maximize service life

MAHLE Original piston ring sets are the preferred choice of professional engine builders. Whether used in a full engine overhaul or targeted compression restoration, the 42001CP.040 delivers OE form, fit, and function with the durability and precision that MAHLE is known for worldwide.