recently while driving between 30 and 40mph down the street my timing belt broke. I didn't hear any real noise, just sounded like the car died. I had it towed to a mechanic friend and he changed the timing belt and water pump, correctly i'm hoping. I tried to start the car and nothing. He tested the compression and he said it is either zero or low in 3 out of 4 cylinders. MY engine is the 2.4L dohc. My question is do i have bent valves or can something else cause this problem? thanks for the help.