Land Rover Repair: 1991 V8 Disco wont start after oil light came on, rotor arm, distributor shaft

Question
Went 4wding in 1991 3.5 V8 Disco and everything was running fine while going through sandy & rocky tracks and over dunes. Upon making our way back, we were going down the beach at around 70kms/hr and all of a sudden the oil light started flickering, I heard a pop sound, the oil light stayed on and then the engine cut out. It now doesnt start, we checked for a spark and there is none and when we pulled the distributor cap off the metal piece of the rotor arm had come off. We managed to find the pieces and put it back on and tried to start it again but it came off again straight away (even though it is screwed in). Checked for compression and that was fine. We replaced the cam and lifters in it about a month ago but it has been heaps better than it was prior to the change. Any ideas what it could be?!?!

Answer
It sounds like something failed in the cam drive gears area.  You will have to remove the front cover to see what's wrong.  If the distributor shaft is not turning the oil pump is not running either.  If you drive any distance like that you will ruin the engine bearings.  I'd tow the truck to a shop right away, and pull the timing cover to see what's wrong.