oil pressure.

[silverado28529]

just finished building my engine for my silverado.Got it back in and started it tonight. after a few minutes the oil pressure dropped. I put a brand new oil pump in when i rebuilt the motor. Ny ideas of what could cause this to happen.Any help guys?

 

[foreman1063]

How much did it drop? At idle? When it warmed up?

 

[Rich]

Having NO idea what generation of motor, size, etc. you have, I can't be of much help. What brand of "brand new" oil pump did you use? What was the cold pressure, at what RPM? what was the "warm" pressure, at what RPM? did it rise with RPM's?