You say that "after 2 kilometers I stop sounding", so I think they were hitting pistons and valves if the distribution is out, because before loosening the belt, do you already make this noise? Did you check the pulle brands before starting? . I think that if the valves had been bent a little, you would have noticed it for lack of strength in those 75 km, if it is a lot, it would have been left without force immediately and stopped you, but it depends on how folded/s that are (hopefully this is not). Nor should we rule out that you have a breakdown in the bomb, because now you say that it does not throw diesel ... there had to be there to see where the pounding came from, from here it is not easy. Greetings!!