my 272 is doing something real interesting twice now on the way to work its lost oil pressure the first time about 3-4 weeks ago then today. today i put a pressure gauge on it & 0 pressure i pulled the pump the drive shaft was in the pump i turned it by hand & it spat oil out so not the pump i got a socket to fit the drive shaft pushed it up into the distributor and tried to turn it not slipping in the dissy put the pump back in & i had oil pressure 45psi at idle same thing happened the first time only i pulled the dissy.

i know its between the dissy & oil pump but the shaft looks fine except for some wear marks each end its also 8 inches long is that the right length guys your help is most welcome as i would like to solve this before my engine with its new crank go bang.

          Is the allen in the bottom of the distributor ok? Or has it rounded out and occasionally slips?

thats what i was thinking but with the sizzy still in place i put the shaft back in put a socket & ratchet on it worked it both ways & couldnt get it to slip at all im thinking of getting a new shaft just to be on the safe side.

my thoughts exactly it had a valvolene filter i changed it to a ryco a couple of months back i had the sump of & cleaned the pickup none the less i blew throug it & it was ok as well.

Possibly sucking air at the ‘O’ ring at the inlet of the pump.  That's at the top of the list for sudden oil pressure losses on the Y.

i put a new o ring on when i pulled the sump after the new crank had done 3000 miles when i pulled the oil pump last saturday i noticed a slice of o ring a couple of thou in thickness & in a full o shape sitting on the pipe its running ok at the moment im hoping it doesnt happen again i still dont know why its still running how do i seal the o ring up so it doesnt suck air.  moz.

I’ll typically use grease or oil on the O ring during assembly so it slides in place without dragging or pinching.  The tube must be in good condition where the seal rides and not crimped from being previously overtightened.  If the tube is not round, then it will need to be straightened or replaced.

the pipe is perfectly straight & not crimped anywhere im going to pull the sump in the next couple of weeks to see if any damage was done i will follow your oil or grease solution then for now the old girl is running like a dram & quiet as a mouse no noises that shouldnt be there.