Stationary engines of ancient design may not be the most suitable for automotive application, but they should not be singled out

Been recently in Uruguay, seen an old Volkswagen Brasilia repowered with a Hatz Diesel inline-twin. Maybe not the best one but at least it retained the air cooling instead of adding the complexity of a radiator, water pump, thermostat valve and all those hoses. Right now in Argentina, soon to go to Namibia. Argentina used to be more receptive toward light-duty Diesel engines, but now it's all about CNG while we only see something Diesel once in a while and mostly a Peugeot or a Renault. Those who would rather want some other light-duty ride with a Diesel, such as a Chevrolet Cruze or a Ford Focus, are left pretty much without any option. It might seem tempting to just slap some stationary engine to a newer car, much like it used to be kinda popular with Perkins engines in other times, but now with all those emission regulations and the widespread of electronic stability controls it becomes roughly impossible to integrate them  to work with a mechanically-governed engine.