Description

The Cummins ISB Piston Ring Set C4089258 (Standard Size) is a precision-engineered ring set designed to restore proper cylinder sealing, compression, and oil control in Cummins ISB diesel engines . Manufactured to OEM specifications, this ring set delivers accurate fitment, reliable sealing performance, and long service life. Designed for standard bore (STD) pistons, this ring set is ideal for engines that remain within factory cylinder specifications. It is commonly supplied as part of the Cummins ISB piston kit C4089669 , ensuring perfectly matched components for consistent compression and balanced engine operation. Each ring is produced from high-strength, wear-resistant materials capable of withstanding high combustion pressures, elevated operating temperatures, and continuous duty cycles common in modern ISB diesel engines. Precision-machined ring profiles promote fast seating, uniform cylinder wall contact, reduced blow-by, and controlled oil consumption. The C4089258 piston ring set is typically installed during ISB engine rebuilds, in-frame overhauls, piston replacements, and professional remanufacturing projects . It is trusted by diesel technicians, fleet maintenance teams, and engine builders who require OEM-quality sealing performance and durability.