Driving home from work last weekend and noticed on my oil pressure gauge that it was low. Checked the pressure relief valve which was fine. Checked the pickup pipe to make sure it ws clear so decided to replace the pump for a new one. Put that on started the car up and the oil pressure was still down by 20psi using the same make and grade oil as previous when I was getting 60psi from cold then 40 psi when warm. I have been told next to make sure none of the crack bearings have rotated and tio check and measure everything. Just wondered if there is anything I shold be looking out for?

Any help on this wold be appreciated.

Cheers
Dave