This paper deals with comparing three types of non-conventional mechanisms of Stirling engines. It is a wobble yoke mechanism, a special type of wobble yoke mechanism and mechanism with ring. The mechanism with a ring was designed as another possible mechanism for structural design of wobble plate in projekt Nonconventional engine FIK –Stirling. The aim is to compare the relative movement of two consecutive pistons in the Stirling engine system and thus evaluate the course compression that arises in one interconnected system of this engine. The paper deals with the dynamic simulation of these mechanisms. The dynamic simulations were made in Autodesk Inventor sofware.