The IC engines construction is usually neglected by the engineers, so because of this, the last few decades cannot notice big changes from the aspect of the construction of engine mechanical parts. The greatest accent was given to the reduction of the exhaust emission, and with this on the IC engines equipment improvement. In the paper was conducted the analysis of the unconventional piston mechanism, as well as the comparison with classic/conventional piston mechanism. Results show a many advantages from the aspect of IC engine construction, reliability, working cycle and performances, which can be achieved with IC engine with this piston mechanism, and small number of disadvantages, which easy can overcome.