If the Centa rollers have gone then the starter motor will only turn the ring gear/clutch/inner Centa assy - i.e. the engine won't turn over. I've never heard this in person but I guess the sound would be a much faster spinning type sound than in the video (stop me if I'm being too technical
) so I like the broken cambelt scenario you offer.
Thats an interesting point I hadn't paid too much attention as to where the starter motor and ring gear are situated, but as you say it is engine, compensator, flywheel/clutch/ring gear/starter motor and then the gearbox.
So if the compensator fails then the engine won't start as there is no connection through to the ring gear/starter motor. If the engine was running when they lost drive and stopped and now won't start after they turned it off that does indeed point to compensator failure, if however the engine cut out when driving then cambelt or fuel pump.
