Mahle 41240CP.030 Engine Piston Ring Set

Overview

MAHLE 41240CP.030 is a premium engine piston ring set built for 4.030-inch bore applications with a 0.030-inch oversize. It combines a carbon steel top ring, cast iron second ring, and stainless steel oil ring assembly to support precise sealing and controlled oil use in performance and rebuild work.

Compatible with select American Motors, Chevrolet, Jeep, Oldsmobile, and Pontiac engines from 1977-1980, including applications such as the Chevrolet Monza, Jeep CJ5, and Pontiac Sunbird. The 41240CP.030 is engineered around OE-driven requirements for reduced friction, lower ring mass, and longer service life.

Key Features

• 4.030-inch bore diameter with 0.030-inch oversize for matched rebuild applications
• Premium-grade piston ring set for engine block service
• Plasma-moly face coating for improved ring surface durability
• Carbon steel top ring, cast iron second ring, and stainless steel oil ring assembly
• Thin axial heights for the top and second rings to support efficient sealing
• MAHLE piston ring technology developed around OE requirements

Detailed Description

MAHLE 41240CP.030 piston rings are designed for engines that need accurate cylinder sealing, stable oil control, and consistent ring performance after machining. The ring package uses a plasma-moly coated top ring, a cast iron second ring, and a stainless steel oil ring assembly to balance wear resistance with low friction. This makes the set a practical choice for rebuilds where bore size and ring material selection matter.

Fitment includes 1977-1980 Pontiac Sunbird, 1978-1980 Chevrolet Monza, and 1980 Jeep CJ5 and CJ7 applications, along with additional American Motors, Oldsmobile, and Pontiac models. This part cross-references Hastings Piston Rings 2M5570030 and Sealed Power E381K30 for the same application. The 41240CP.030 is a direct-fit piston ring set for compatible engine builds that require a 4.030-inch bore and 0.030-inch oversize specification.

Common Issues It Can Address

• Excessive oil consumption from worn or out-of-spec rings
• Loss of cylinder compression during engine rebuilds
• Ring wear caused by high-friction or degraded ring surfaces
• Poor sealing after cylinder boring or honing
• Reduced engine efficiency from worn piston ring components

Installation Notes and Tips

Verify bore diameter, oversize requirement, and ring groove dimensions before installation. Match the ring set to the finished cylinder bore and follow the engine builder’s end-gap and clearance specifications. Clean cylinder walls thoroughly and inspect piston ring lands before assembly. Confirm application details against the vehicle and engine combination for the Chevrolet Monza, Jeep CJ5, and Pontiac Sunbird fitments listed.

Quality Assurance

MAHLE develops piston rings around OE requirements and focuses on reduced friction, lower ring mass, and extended service life. The 41240CP.030 reflects that engineering approach with premium materials and a plasma-moly face coating for demanding engine rebuild applications.