This study investigates the combined use of ammonia and biodiesel as fuels in a 7.5 kW compression ignition engine. The work is part of the Polish/Norwegian project ACTIVATE working on developing a medium duty engine running on ammonia and biodiesel for agricultural machines such as tractors. Using ammonia as fuel has the benefit of reducing CO2 emissions to the atmosphere compared to its fossil alternatives in internal combustion engines. However, there is still a large knowledge gap on the fundamental and technical aspects of combusting ammonia in an engine, and ammonia is known to have adverse effects on combustion such as low laminar flame speed and high ignition energy. In this study, the chosen strategy is run the engine in dual fuel mode where the aim is to use ammonia as the main fuel and initiating/enhancing combustion by using biodiesel as pilot injection. Liquid anhydrous ammonia is injected into the engine cylinder using a GDI injector, simplifying the fuel conditioning system and potentially reducing ammonia slip. This work presents the engine test cell at NTNU and preliminary results of biodiesel reference cases and ammonia/biodiesel cases in terms engine performance.