MAHLE 42278CP.040 Engine Piston Ring Set - .040 Over Premium Replacement

The MAHLE 42278CP.040 is a premium OE-replacement engine piston ring set machined to .040" oversize specifications. MAHLE is one of the largest OE piston ring manufacturers in the world, and this set is engineered to deliver OE form, fit, and function for a precise, reliable engine rebuild.

Key Features:

• OE-quality construction — designed to meet original equipment form, fit, and function standards
• SAE 9254 high-alloy steel base material — delivers higher tensile and yield strength, extended fatigue resistance, and increased material hardness
• Pre-lapped rings — seat immediately upon installation, virtually eliminating break-in time
• Optimized ring tension and coatings — materials are application-matched to reduce friction and extend service life
• Barrel-faced compression ring contact area — promotes more efficient compression sealing and reduced blow-by
• CNC-controlled gap chamfer — optimizes compression and minimizes combustion gas leakage
• Reverse-twist intermediate rings — provide improved groove side sealing with taper race machining for enhanced contact
• CP-20 oil ring assembly — features a 20-degree ear angle for superior cylinder wall side sealing, with a chemically polished expander for enhanced oil drain-back
• .040" oversize — engineered for use with bores machined .040" over standard diameter

MAHLE Original piston ring sets are a top choice for professional engine builders and rebuilders, combining advanced metallurgy with precision manufacturing to minimize oil consumption and deliver long-lasting performance.