So that pankl crank drive components can also be tested in the future under the constantly increasing loads, especially in Formula 1, a completely new single–cylinder test bench engine was developed and designed for the 2021 Formula 1 regulations. In this thesis, a thermal and mechanical FEM – simulation of the newly developed test bench engine under peak pressures from up to 400 bar is carried out on the basis oft he existing engine geometry from CAD and an engine process calculation provided. In addition, a strength verification of selected components is carried out. The aim is to be able to calculate the occurring loads in the engine structure during the ongoing development process and to be able to carry out improvement measures before a first prototype is built. After a suitable calculation model was created in the first step, the coolant jacket was then calculated with the aid of the coupled use of FE- and 3D-CFD–simulation. The analysis of the results revealed a great potential for optimisation, especially in the inlet area. Thereupon a flow straightener was developed and designed, which is specially adapted to the cooling jacket geometry. In addition, the transition between the inlet and cylinder areas has been modified in terms of design. By integrating the newly developed flow straightener in the inlet channel, combined with the optimised transition area, the pressure losses can be reduced by approx. 51% compared to the original geometry. Furthermore, the turbulences in the flow is also massively reduced. The distribution of the heat transfer coefficients is much more uniform due to the optimisation and results in slightly higher values. The temperature field of the engine was calculated for both the original geometry of the engine and for the optimised cooling jacket geometry. With the optimised cooling jacket, a reduction in temperature of up to 4,4% for the upper part of the engine block and up to 3,3% for the liner can be achieved. With the help of the knowledge gained from the CFD simulation, the potential for improvement of additively manufactured flow guide components in the cooling jackets of single-cylinder engines has become clear. Based on the mechanical FEM-simulation, the strength calculation could finally be carried out. The safety against fatigue fracture was proven for all selected components. This ensures operation at peak pressures of up to 400 bar.