Are presented the simulation results of the crankless mechanism of the engine with external combustion by means of the built-in module of the dynamic analysis of an ‘Autodesk Inventor package’ and the ‘Rigid Dynamics’ module of an ‘ANSYS’ package. Physical experiment is made. Results of numerical modeling and physical experiment iscompared.The experience of the application of innovative approaches to the measurement of the dynamic characteristics of the piston during operation of the mechanism. Identify promising for further work to improve the measurement system. Increased stability and accuracy of measurement will identify vibration load of the piston in the extreme positions. This will increase seal life by taking into account these loads at the design stage.