I assume you did drain the oil cooler and installed a new filter....

You should fill the oil cooler (take off one line and fill) and do the same for the the oil filter (can be be messy).
Then you should have oil pressure within seconds (say 3-5) when cranking.

I do not crank till pressure builds rather double check everything and have it fire as soon as possible. then run at about 2500 for 10 minutes. (Lots of parts are lubricated by splash and there is little of it at idle.) my .02
Hope that helps

Mike (Germany)
89 M3
95 525 TDS Touring
68GT500
65 Mustang convt.

Ive just done some engine work - big end bearings replaced and head / chain done. Ive come to turn over engine (plugs out) but no oil pressure - at least light stays illuminated. At this point I stopped cranking. How long should oil pressure take to circulate after the engine has been entirely drained. What should oil pressure be. Does anyone have any fault finding tips.

I really need assistance.

Thanks in advance

Follow Mike's advice, and also check to see if the oil pressure wiring is connected. You or someone else may have disconnected it while doing the engine work. It's the brown connector. If that doesn't fix it, replace the oil pressure switch. It's cheap.

JamesM