MAHLE 50203CP Perfect Circle Standard Piston Ring Set 4.250" Bore V8

The MAHLE 50203CP is a standard-bore piston ring set engineered for Big Block V8 engines, designed as a direct OE-quality replacement for engine overhauls and re-ring jobs. Formerly marketed under the Perfect Circle brand, this ring set carries on a tradition trusted by professional engine builders for over 100 years.

Ring Specifications:

• Bore Size: 4.250 in. (standard)
• Upper Compression Ring (UCR): Cast iron, RF-10 type, 5/64 in. axial height, positive twist with barrel face for rapid break-in
• Lower Compression Ring (LCR): Cast iron, BT-10 type, 5/64 in. axial height — provides superior combustion gas management and top ring stability
• Oil Control Ring (OCR): 3-piece CP-20 type, stainless steel expander with two chrome-faced steel rails, 3/16 in. axial height
• Configuration: V8 (8-cylinder), sold as a complete set

Key Features:

• OE form, fit, and function — designed to meet original equipment specifications
• High tensile strength and high yield strength with low ring mass for stress resistance and minimal groove pound-out
• Exclusive CP-20 oil rings with 20-degree ear angle for optimal side seal in the piston oil ring groove
• Chrome-faced oil rail expander for high conformability within the cylinder bore
• Engineered for long service life, excellent cylinder conformability, oil economy, and low blow-by
• Foolproof design prevents incorrect installation

The MAHLE 50203CP ring set is an ideal choice for engine rebuilds requiring reliable sealing, reduced oil consumption, and consistent performance across a range of operating conditions.