MAHLE 3150034 Plasma-Moly Ductile Piston Ring Set 4.000 in. Bore 8-Cylinder

The MAHLE 3150034 is a Plasma-Moly Ductile Piston Ring Set engineered for serious performance and racing applications. Designed for a 4.000-inch standard bore on 8-cylinder engines, this complete ring set delivers exceptional combustion sealing, reduced friction, and superior oil control under demanding conditions.

Ring Dimensions:

• Top Ring: 5/64 in. — Reduced Radial Wall (RRW), plasma-moly face coating
• Second Ring: 5/64 in. — Napier THG (tapered hook groove) design
• Oil Ring: 3/16 in. — CP-20 low-tension oil control ring

Key Features:

• Plasma-Moly Face Coating — Applied to SAE 9254 carbon steel using a proprietary plasma process for extended service life, reduced side wear, and resistance to ring breakage
• Reduced Radial Wall (RRW) Top Ring — Allows the top ring groove to be positioned closer to the top of the piston, reducing crevice volume and unburned fuel emissions
• Lower Ring Mass — Smaller cross-section reduces inertial forces at high RPM, improving ring-to-groove sealing at both TDC and BDC
• Napier THG Second Ring — Tapered hook groove design scrapes cylinder walls on each downstroke while providing a controlled oil reservoir, improving combustion gas management and top ring stability
• CP-20 Oil Control Ring — Named for its 20-degree ear angle, this exclusive design provides maximum cylinder wall sealing while minimizing tension for reduced friction losses
• Standard Tension — Recommended for street, racing, and marine applications

MAHLE is the world's largest piston ring manufacturer, with over a century of OEM and aftermarket engineering expertise. The 3150034 ring set is built to withstand higher RPM, elevated compression ratios, and extreme operating temperatures that modern performance engines demand.