The paper describes the methods used to select appropriate engines for renewing an existing fleet of fork lift truck models with new Diesel and LPG engines. The target was to achieve a better performance with the new engines and to find a better cost / benefit ratio for the customer. The aid of a simulation was used to fulfill this task.Selecting suitable engines from a variety of industrial and mass production passenger car engines which fulfill above requirements seems to be an easy task on first sight, but looking at the details the matter becomes more complex. Of particular interest were the effects of replacing naturally aspirated (NA) engines by smaller swept volume turbocharged (TC) engines.A power train simulation model including the hydraulic lift part was developed and used for Diesel and LPG engines. For several different operating situations and load profiles a set of simulations was performed for different engines. With this method a pre-selection of suitable engines was carried out.Not only the engine selection is possible with the performed simulation. In addition effects like dynamic behavior of the engine and load response at different operating modes can be detected and analyzed before real hardware is built and tested. This applies especially for dynamic effects of turbocharged engines and dynamic load responses.