At the design of heat engines like Stirling engines are, it is possible to use not only classical crank mechanisms, but also non-conventional mechanisms. Engines with non-conventional mechanisms may have several advantages when used in practice, but the design calculation model is often more difficult. This paper deals with the design of the measuring system for the measurement and diagnostic of basic parameters of the thermal cycles in Stirling engine with nonconventional FIK mechanism, which was solved in the project VEGA: Nonconventional engine FIK – Stirling. The measuring system concept is applied to a special type of piston machines with swinging mechanism that is used in this instance of a Stirling engine type. Stirling engines are currently usually used as a drives of machines for production of the electricity. There are several types of mechanisms, which are suitable by design for use in a Stirling heat engine. FIK mechanism is a swinging system, which is characterized by circular motion of the central point of the swinging plate during the rotation of the shaft. Proposed measuring systems allows to confirm the functionality of the structural design of Stirling engine with a swinging plate and examine the thermodynamic phenomena conducted in the engine cylinders.