Description

The Cummins Steel Top Piston Assembly M-8673-100 (1.00 mm Oversize) is a heavy-duty replacement piston designed for diesel engines that require maximum durability after significant cylinder boring. Featuring a steel crown (steel top) design, this piston assembly replaces Cummins OE part number 3802761 , delivering OEM-accurate fitment, correct compression height, and optimized combustion geometry. Engineered for Cummins diesel engines , the steel top construction provides exceptional resistance to extreme combustion temperatures and high cylinder pressures. Compared to conventional aluminum pistons, steel crown pistons offer superior thermal stability, reduced crown fatigue, and extended service life—ideal for severe-duty, high-load, and emissions-controlled applications. The 1.00 mm oversize specification is intended for engines with heavily bored cylinders, restoring proper piston-to-wall clearance, compression, and combustion efficiency. Precision-machined ring lands, an optimized skirt profile, and a robust internal structure help reduce friction, control thermal expansion, and maintain piston stability during continuous operation. The Cummins M-8673-100 steel top piston assembly is commonly used during full engine rebuilds, in-frame overhauls, and professional remanufacturing projects . It is trusted by engine builders, fleet maintenance teams, and diesel repair facilities that demand long-term reliability and consistent performance.