Cummins 4059900 Piston Assembly

The Cummins 4059900 piston assembly is designed for the M11 engine platform, including ISM11 and QSM11 variants. It features a 125 mm bore diameter and aluminum alloy construction optimized for high thermal conductivity and structural integrity under heavy-duty combustion cycles. This component serves as a direct replacement for OEM part numbers 4059900 and 4914368, and supersedes kit references 4025161 and 4059901. The piston is applicable to engines produced by Chongqing Cummins (M series, QSK series), Xi'an Cummins (ISM series), and Dongfeng Cummins (QSL series). Typical equipment fitment includes Hitachi off-highway dump trucks, Sany heavy dump trucks, and Hyundai R485 hydraulic excavators. The assembly includes piston crown, skirt, pin bore, and ring groove geometry calibrated for Cummins M11 fuel injection and compression ratios.