Description

The Cummins 6.7 ISB Steel Crown Piston M-8619 (Standard Size) is a heavy-duty piston assembly engineered for high-output diesel engines that operate under extreme combustion pressure and elevated exhaust gas temperatures. Designed as a direct replacement for OE piston numbers 5258754 and 5258755 , this piston delivers OEM-correct fitment, durability, and long service life in Cummins 6.7L ISB diesel engines . Steel crown pistons are used in modern common-rail diesel platforms to handle higher thermal and mechanical loads than conventional aluminum pistons. The steel crown construction improves resistance to cracking and crown deformation, supports higher cylinder pressures, and enhances overall piston longevity—making the M-8619 piston ideal for turbocharged and emissions-controlled ISB applications. This piston features precision-machined ring lands, controlled thermal expansion geometry, and an optimized skirt profile to reduce friction and maintain piston stability. When installed with the correct piston ring set, piston pin, bushings, and retainers, it helps restore factory compression, reduce blow-by, and control oil consumption. The Cummins M-8619 steel crown piston is commonly installed during 6.7 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-level strength and reliability. Cross-Reference (OEM) Aftermarket Reference: M-8619 OEM References: 5258754, 5258755 Engine: 6.7L ISB Size: Standard (STD) Type: Steel Crown Piston