My cam pully broke in two and this also smashed the plastic cover, engine stopped immediately, no bang, was on a roundabout going pretty slowly. Will put up the photos so you can see. Just wonder if any one else has ahd this. Will pull it to bits at the weekend to see exactly what has happened. Mine is a 1982 Euro s 4.7. I bet I have bent the valves.

 

I'm guessing you have more than a broken cam gear. I bet that camshaft is toast.

 

Oh snap.

 

valves probaly are ok, but thats easy to check once you get things apart. the 82 piston pockets are REALLY deep. almost .3". cam lift is only .45" and there is some space between valve seat and piston.
I notice touching of valve to piston pocket with .175 cuts, with .3" valve depression so its safe to say, that tere is no contact with a .350" valve pocket. but you never know!!

 

I had a US 82 crack the right hand cam gear it took out the left side cam as the snout snapped off
NOTE Left/ right side is seen while sitting in the car looking forward))
the possibility that caused the damage was worn gears and possibly an over torqued ( stretched)RH cam pulley bolt also the timing belt tension was tight the Kempf tool on the older before S4/32Valve versions should be at the low side of the window

 

You might want to edit the title since the T-belt did NOT FAIL......