This may exist elsewhere, but a search didn’t find exactly what I was looking for. Drag and drive project, Gen 4 SBE with a 78mm turbo. All new bearings, rings, everything cleaned up or new, started with a bare block. 15-40 rotella conventional, wix filter. Melling m295 pump, not HV or high pressure. Pressure starts around 50-52 at cold start. Falls to around 40-42 at 180 idling at 850 rpm. Will climb to 60 revving. Cruising, the pressure will slowly drop, and will climb less as you rev the longer you run it. After you drive about 10 miles, the pressure will drop to 18-20 at idle. No concern there.. but it’s only running around 35 or so at 4500-5000 rpm at that point. Changed the oil just before these numbers, as I drove it about 20 miles the other day and oil pressure fell to 8 psi (blipping back and forth from 8-10 at idle) and I got nervous. Was only at about 23 psi at 3000 rpm on the way home. Oil had been changed less than 50 miles before that. Nothing in the oil, nothing on the magnet. Would think if I had a bearing issue, a: I’d see something and B: the cold start pressure after a change would continue to decrease when actually it increased about 4 pounds on this change. I did drill out my turbo oil feed restrictor a touch as was recommended to me, but at most I would think that would rob a pound or two, maybe 3 at most. Should probably be using a hv pump, maybe both hv and hp. Engine is going to have to come out, but was hoping to drive it a little more this fall while the weather is good before I pull it even though it’ll only take a couple days to pull and put it back if I only do a pump. I have a feeling that’s not gonna do the trick though so looking for thoughts before I pull it. I really don’t think it’s the o ring on the pump pickup, I put a new green one in when I put it together, and everything felt like it seated correctly. Running 7 quarts so cavitation should be a non issue. New barbell/dogbone, whatever you want to call it. I imagine it’s possible I missed a gallery plug, but not way it’s putting out decent pressure at start with one of those missing. Appreciate any ideas y’all have.

 

Finally found a nearly identical thread, wasn’t searching back far enough. Sounds like while I have it out to replace oil pump, better pull the pan to check rod bearings even though I’m not seeing anything glitter-wise.

 

What oil pan? Wondering why 7 quarts. Too much oil and you run into similar problems due to frothing, although I don’t suspect you’ll have that issue with 7 quarts, unless your running a small pan.

 

6 qt low clearance musclecar pan (common pans wouldn’t clear my rack). Only difference is it’s 1/2” thinner up front. Was having the same issue running 6qts. Upped it to 7 just to see if it made a difference, thought maybe the extra oil for the turbo could be dropping it a little too much. 4an line but runs all the way from the filter housing and around the front to the upper passenger side.

 

needs oil pump imo