MAHLE 40069CP.040 Perfect Circle Premium Piston Ring Set Over - 0.040

The MAHLE 40069CP.040 is a Perfect Circle premium piston ring set ground to a 0.040" overbore specification, engineered for engine rebuilds and re-ring jobs demanding OE-quality materials and reliable sealing performance. MAHLE, the world's largest manufacturer of piston rings, brings decades of original equipment development directly to the aftermarket through the Perfect Circle premium line.

Key Features:

• Premium moly or chrome-faced top compression ring for long service life under demanding operating conditions
• Barrel-faced compression ring contact area for efficient compression sealing and reduced blow-by
• CNC-controlled gap chamfer on compression rings to optimize sealing and minimize combustion gas leakage
• Reverse-twist intermediate rings with taper-face machining for superior groove side sealing and enhanced cylinder wall contact
• CP-20 3-piece oil ring assembly featuring a 20-degree ear angle for maximum side sealing against the cylinder wall
• Stainless steel oil ring expander with chemically polished surface for enhanced oil drain-back
• Pre-lapped finish allows rings to seat immediately, virtually eliminating break-in time
• Installer-friendly design — rings are engineered so they cannot be installed incorrectly
• 0.040" overbore specification for use with bored or worn cylinders rebuilt to this oversize

Ring materials, coatings, and tension values are application-optimized to minimize friction while maximizing compression retention and oil control throughout the engine's service life. Whether tackling a full engine overhaul or a precision re-ring, the MAHLE Perfect Circle 40069CP.040 delivers the quality and consistency trusted by professional engine builders.