oil pressure sender

[mjzakowski]

Hello
I have new engine put in the bird before I brought it.
It has less than 20,000. miles on it now. If the oil pump works when
it is cold and shows pressure and still shows pressure after it gets
to running temperature, Why would the pressure gage go down to zero
reading after driving hour to hour and half?
Also I did detected a slight oil leak at the sender unit. Do you think
this might be the problem?
Joe in IN
1984 1/2 pt 40 6v92