Preliminary designs for the cylinder heads of Scania’s next generation Diesel Engine have been investigated by the means of PIV measurements on a steady test rig. General structures present in the flow have been investigated, with a specific focus on Swirl motion due to its well documented impact on combustion efficiency and pollution generation. The first set of measurements was acquired in the tumble plane. A method to perform efficiently PIV measurements was introduced, which consists in rotating the experimental setup rather than the PIV measurement instruments. As a consequence, a considerable amount of work is saved and a great number of measurement planes can be acquired. This method has allowed to reconstruct a 3D3C picture of the flow in the cylinder. Such 3D3C direct measurement of flow in a test rig cylinder had not been reported previously in the literature, as far as the author is aware of it. The second set of measurements was acquired in the swirl plane. General patterns in the swirl velocity fields have been identified. The author introduces the hypothesis that shifting down the measurement position may, to some extend, be equivalent to observing the flow evolve in time in the real engine situation. Measurement performed far enough under the valves exhibit clear and stable swirling vortex structure with the cylinder heads investigated. This may explain for the validity of the combustion models used in the industry that, despite apparent over simplification of the flow situation, have proved in good agreement with engine tests.