On my 87 Monte SS, i have no oil pressure at all. My first diagnosis is that my oil pump took a crap on me. My new oil pump should arrive today and be installed. Just wanting to get others opinions on what could also be wrong? I did an oil change not that long ago and i checked it when i noticed no oil pressure and it was completely full. Though i should point out that when i did my oil change, alot of sludge came out and im guessing my oil pump got clogged due to the amount of sludge. (Yes i DO take care of my engine despite saying that where was sludge.) I also have a spare oil pump shaft that i will be installing along with the oil pump. Any other ideas on what it could be?

 

My second guess is that the passages to move the oil are plugged up with the sludge you described.
Some might recommend running some "motor flush", I recommend against that. I've heard more harm then good from that stuff.

I'm trying to think without a complete tear down, how would one clean out sludge. You could take the valve covers off, clean the rockers and push rods. Then wipe EVERYTHING down that you can access. Possibly increase your oil changes and use an additive like Rislone that is supposed to clean crud from the engine (again, not "motor flush", Rislone is like oil but whatever it does, does not appear to have the harmful value of Rislone). By changing your oil say every 1000 miles and using something like Rislone, you will hopefully be "flushing" the crud out of the engine.

That's the best thoughts that I have at the moment. I'm not even sure how good these thoughts are.