MAHLE 4040MS-112D Drop-In Piston Ring Set 4.040in 1.0mm x 1.0mm x 2.0mm

The MAHLE 4040MS-112D is a performance drop-in piston ring set engineered for a 4.040-inch bore with a 1.0mm top ring, 1.0mm second ring, and 2.0mm oil ring configuration. As a drop-in set, these rings are pre-gapped and ready to install without file-fitting, making them ideal for engine builders looking for precision and convenience.

MAHLE Motorsports developed this ring set using advanced piston ring simulation and computer engineering tools to minimize friction and deliver measurable power gains. The result is a ring pack that performs on both the street and the track.

Key Features:

• Drop-In Ready: Pre-gapped for the specified 4.040-inch bore — no file-fitting required
• Ring Pack: 1.0mm top ring / 1.0mm second ring / 2.0mm oil ring
• Steel Top Ring with HV385 Coating: Features MAHLE's patented supersonic thermal spray process for superior bonding, increased durability, and enhanced scuff resistance
• Steel Napier Second Ring: Engineered for superior oil control and reduced blow-by
• CP-20 Oil Ring: Industry-leading 3-piece standard tension oil control ring for reliable, consistent performance
• Ultra-Flat Ring Flanks: Precision-finished flanks maximize ring-to-piston groove sealing
• Standard Tension Oil Rings: Included for optimized oil control in performance applications

This ring set is part of MAHLE's well-regarded 1.0mm x 1.0mm x 2.0mm performance lineup, commonly used in high-output V8 builds. Note: This product is not CARB compliant and is not legal for sale or use in California emissions-controlled applications.