Description

The Cummins Piston 3923165 (Standard Size) —commonly identified by the “3165” crown marking —is an OEM-spec piston component designed for 6CT 8.3 diesel engines . Manufactured to precise factory tolerances, this piston provides accurate fitment, stable compression, and long-term durability in Cummins engines . Piston crown markings are critical during engine assembly to ensure the correct piston variant is installed for the specific engine configuration. The “3165” marking corresponds to part number 3923165 , helping maintain proper compression ratio, combustion geometry, and emissions performance when rebuilding or servicing 6CT 8.3 platforms. This piston features precision-machined ring lands, controlled thermal expansion characteristics, and an optimized skirt profile to reduce friction and maintain piston stability under load. When paired with the correct piston ring set, piston pin, bushings, and retainers, it helps restore factory performance, control oil consumption, and reduce blow-by. The 3923165 piston is commonly installed during 6CT 8.3 engine rebuilds, in-frame overhauls, and professional remanufacturing projects . It is trusted by diesel technicians and engine builders who require OEM-level reliability and correct piston identification. Identification & Fitment Notes Part Number: 3923165 Crown Marking: “3165” Engine Platform: Cummins 6CT 8.3 Size: Standard (STD) Category: Piston & components Fitment Note: Always verify crown marking and engine specs before installation.