I'm not sure why that happens but I've seen it a couple times. I don't know which piece breaks first and causes the damage.

 

Does anyone know where to buy the tool for setting the Cam Sensor? (with out spending too much money). I've got my engine (97 4.2 in f-150) ready to drop down in. And I've already spent WAY too much money on this thing. (I still love my truck but this engine is the worst designed piece of work I've ever seen) Any ideas would help. I'm only going to use this thing once and after that it's for sale......any problems with this engine again and I'm getting something with a 350 chevy in it.............