MAHLE S42221.040 Premium Piston Ring Set Oversize - 040

The MAHLE S42221.040 Premium Piston Ring Set delivers OE-quality performance for engine rebuilds requiring .040 inch oversize rings. This single-cylinder ring set is engineered with precision-machined components designed to provide superior sealing, compression retention, and oil control.

Advanced Ring Construction:

• Upper compression ring (UCR) constructed from ductile iron with ceramic chrome facing for exceptional wear resistance and sealing
• Lower compression ring (LCR) made from premium cast iron for reliable performance
• Oil control ring (OCR) features cast iron construction with chrome facing
• SAE 9254 high alloy steel base material provides higher tensile strength, extended fatigue resistance, and increased material hardness

Precision Specifications:

• Upper compression ring axial height: 3.0mm
• Lower compression ring axial height: 2.38mm
• Oil control ring axial height: 4.0mm
• Ring types: UCR (RFK-18U), LCR (BT-10), OCR (GCL-40UAW)
• .040 inch oversize for precision bore matching

Premium Features:

• CP-20 oil ring design with exclusive 20-degree ear angle for superior side seal in the piston oil ring groove
• Advanced napier second ring design for improved combustion gas management and top ring stability
• Engineered to reduce friction and ring mass while minimizing oil consumption
• Designed to meet OE form, fit, and function specifications

MAHLE is one of the world's largest OE piston ring manufacturers, providing the most technically advanced piston ring technology in the industry. Each ring set is precision-engineered to deliver optimal performance, extended service life, and reliable sealing for demanding rebuild applications.