Oil pressure went to zero while driving

Hey Guys , my string of bad luck continues just had shoulder surgery from totaling my Harley. Took my 72 Buick GS out of storage and tuning the car getting it ready to sell if need be. Its a 470 built by Automotive Machine and Performance years ago. Maybe 5K miles on the motor if that. Always runs strong with no known issues. Cruising tonight at around 4000 rpm the oil pressure gauge went down to zero. No noise from the engine , pressure would go back up to about 20 at very slow speed and I parked it. Any help or ideas of where i should start looking for the problem short of pulling the engine and taking it apart would be very appreciated

Thanks Guys Chris

 

Doesn't sound good,..that's exactly what one of my engines done at the 2014 Nationals driving there and went from 30 to 0 at a red light,..psi would barely come up to 20 with decent rpm,..Mike at Wildcat said upon inspection was the pickup tube had cracked at the base. Bearings all looked great engine had around 5k on it also

 

If no noise maybe a stuck relief valve.pull that big nut off the pump and see if the valve is free.?? How old is the oul.pull the filter off and cut it open.

 

Thanks Guys , going at it tomorrow morning with my one good arm to see what i can find. SWhat are some more severe issues that would cause the 0 oil pressure ? Spun cam or crank bearing ? Thanks

 

Bad oil or plugged filter. Give it an oil change and see what happens.

 

2nd the stuck open relief valve, easy to check first.

 

Thank guys for all the help , hoping its not badly damaged could really use a break for a change

 

I was thinking the same thing Larry , the motor was warmed up with all oil circulated before it went to zero so thought maybe it survived a little on that. Headers and 3" exhaust the car is very loud at around 600HP and idles at 1,000 rpm but I did not her any lifters or knocking

 

I would plumb in a mechanical gauge directly into the block oil galley, remove the distributor and run pump with a drill. This way avoiding any further damage to the engine checking for pressure. I agree with Larry’s statement no noise no damage, but I would take no chances. Then continue troubleshooting if needed.

 

Is it a stock gear oil pump or high volume ?

 

I believe maybe stock but with booster plate ?

 

Broken gear in the high volume oil pump Lost oil pressure to 30 pounds max No noise ended up taking out the bottom end.

 

Definately not going to run it , any idea where to buy the priming tool ?

 

I was running 2050 Motor at the time it was very cold out ended up cracking a gear car ran great at the track in the fall was just running out of fuel so over the winter I worked on the fuel system Took the car out a few times in the spring and that's when I developed a oil pressure loss.

 

I wonder how long a warm motor would last with the 0 oil pressure ? I am probably screwed just hoping

 

You can make prime tool out of an old junk distributor if you have one.

 

Make sure you use a half inch drill.

 

Slow RPM ?