Mahle 51240CP.020 Engine Piston Ring Set

Overview

MAHLE piston ring set 51240CP.020 is a standard 0.020-inch oversize ring set for 4.020-inch bores. It is built for engines that need precise ring sealing, controlled oil use, and reduced friction in a rebuild or overhaul.

Compatible With classic applications including Chevrolet Monza, Pontiac Sunbird, and Jeep CJ7, this MAHLE piston ring set 51240CP.020 follows OE-driven engineering priorities for service life and efficiency.

Key Features

• 4.020-inch bore diameter with 0.020-inch oversize sizing
• Cast iron top ring and second ring for durable sealing performance
• Stainless steel oil ring assembly for stable oil control
• Non-coated ring face for a straightforward replacement specification
• Standard grade construction for rebuild applications

Detailed Description

MAHLE 51240CP.020 piston rings are engineered around OE requirements, with a focus on lowering friction, reducing ring mass, and helping control engine oil consumption. The ring package uses cast iron for the top and second rings, paired with a stainless steel oil ring assembly, giving the set a balanced material mix for sealing and oil management. The 0.020-inch oversize dimension makes this set appropriate when the cylinder bore has been machined for oversize rings.

This part cross-references Hastings Piston Rings 5570020 and Sealed Power E381X20 for the same application. For buyers searching for a piston ring set for Chevrolet Monza, Pontiac Sunbird, or Jeep CJ7 engine rebuilds, MAHLE 51240CP.020 provides a direct-fit specification for the listed bore size and oversize requirement.

What It Helps Address

• Excessive oil consumption from worn ring sealing surfaces
• Compression loss caused by ring wear or cylinder wear
• Friction buildup that can affect engine efficiency
• Rebuild needs after cylinder boring to 0.020-inch oversize
• Oil control issues in older engine assemblies

Installation Notes

Verify bore diameter before installation and confirm the cylinder has been machined for 0.020-inch oversize rings. Match the ring set to the engine’s measured bore and follow standard ring gap, orientation, and break-in procedures during assembly. Fitment includes 1977-1980 Chevrolet Monza, 1977-1980 Pontiac Sunbird, and 1980 Jeep CJ7 among other listed applications.

Quality Assurance

MAHLE piston rings are developed to OE-level requirements and are positioned around friction reduction, oil control, and service life. Part number 51240CP.020 reflects MAHLE’s technical approach to engine sealing components.