MAHLE 3150034-030 Plasma-Moly Precision-Ground Performance Piston Ring Set 4.030" Bore

The MAHLE 3150034-030 is a plasma-moly precision-ground performance piston ring set designed for 4.030" (102.362mm) bore applications. Built from SAE 9254 carbon steel with a proprietary plasma-moly face coating, this set delivers superior tensile strength, hardness, and fatigue resistance for demanding street, racing, and marine applications.

MAHLE's reduced radial wall (RRW) design moves the top ring groove closer to the top of the piston, reducing crevice volume and unburned fuel while lowering ring mass for better tolerance of inertial forces at high RPM. The plasma-moly face coating extends ring life, eliminates ring breakage, reduces side wear, and minimizes groove pound-out.

Key Features:

• Bore Size: 4.030 in. (+.030" oversize) / 102.362mm
• Top Ring: 5/64" — Barrel-faced plasma-moly SAE 9254 steel; provides instant break-in and maintains cylinder wall contact at TDC and BDC
• Second Ring: 5/64" — Napier tapered hook groove (THG) design for superior oil control, improved combustion gas management, and enhanced top ring stability
• Oil Ring: 3/16" — CP-20 three-piece design with 20-degree ear angle for maximum cylinder wall seal and superior oil drainback
• Tension: Standard
• Radial Wall: Reduced Radial Wall (RRW)
• Material: Carbon Steel with plasma-moly face coating
• Cylinder Count: 8-cylinder (sold as a complete set)
• File Fit: No (pre-gapped)
• Gapless: No
• Gas Ported: No

MAHLE is the world's largest manufacturer of piston rings, with over a century of OE and aftermarket engineering expertise. The 3150034-030 is engineered for performance builders seeking maximum combustion sealing, reduced frictional losses, and reliable oil control in high-output, high-RPM engine builds.