In this paper we analyze how car users frame car engines. Car engines have been build on internal combustion (IC) technologies for more than hundred years now; however, in the last decade hybrid-electric engines have been successfully introduced. The coexistence of conventional and unconventional technologies raises the interesting question to what extent these different engine technologies are framed differently, and how they change over time. Studies of technological frames and mental models suggest that frames of established technologies are more obdurate. In this paper we analyze technological frames of a few types of car engines and how frames have shifted during market evolution between 1990 and 2005. We find that engines are framed rather differently. Frames of conventional diesel engines emphasize engine capacity (measured in kW), engine volume (measured in liters) and torque (measured in Nm), whereas for hybrids fuel efficiency is by far the most prominent attribute. Further we find that the frame of the conventional engine (diesel) is more stable than that of an unconventional engine (hybrid and full-electric), which confirms the obduracy hypothesis that is raised in earlier studies of technological frames.