I've put together a new 440 build and i'm at the point of priming the oil system. the machine shop supplied a standard volume oil pump[ Melling , m-63] .
I,m using driven brand 5w30 break in oil. Using a 1/2 inch electric drill i can only get 40 psi of oil pressure. The crank main bearing clearance is .0027, rod bearing .0024 .it is a solid flat tappet cam with EDM lifters , Hughes engine brand 1.6 roller rockers and 240 trick flow heads. I have oil flow out of the rocker arm assemblies as i rotate the crank. So my question is ... Is this normal / typical pressure with a standard pump ? I have always used a hv pump in the past with 60 psi or better when priming the oil system.

Drill speed makes a big difference. A HV pump has more oil sooner,so higher oil pressure at lower RPM's.

Run it and see what you have but I'd bet your hot idle PSI will still be 40-45.

1/2" drills typically turn pretty slow, take the RPM of your drill and divide it in half. Probably lower than the engine will ever idle.

i would struggle on my street car block to get 50 psi when it was cold & by the time it was hot it was just under 10 psi at idle. that was with 10/40 synthetic oil & a HV pump with external static pickup. I bought one of those DIY lifter bushing kits & now its 70 psi cold & 20 psi hot at idle. I'm a firm believer in those kits now, would never run a stock block without this mod.

A quick check would be to use a 3/8 drill motor.. I have the same issues
with EDM lifters.. at rpm I can only get 50psi and it doesnt matter
what RPM.. it runs fine but doent get higher psi.. I have tried both
the standard pump and HV with no change.. I still believe its the
EDM lifters.. this is a SB but I'm sure that BB and SB are the same

Keep in mind that the cam turns half the speed of the crank. A 1/2 drill speed would be around 600 rpm meaning the crank would be turning 300 to achieve that. Not anywhere close to idle speed. I think the pressure you're getting is fine. I only get 25 psi when I prime mine

i did look into the drill motor rating and it is 3000 rpm. i doubt it is turning that fast loaded by the oil pump but even at half that rating say, 1500 rpm , that is 3000 rpm engine speed. and to only 40 psi with cold oil concerns me. just looking for a response from someone with experience using or trying a standard type pump. btw the machine shop told me to run it with the standard pump and see what i have. that makes me uncomfortable.

When in doubt, change it out
That is my motto now, I hate it when some part fails that I had doubts about using

You are making a mountain out of a mole hill. That drill isn't turning the oil pump at 1500 RPM's. If it was, that's a 750 RPM idle and that's lower than I let anything idle with other than stock springs.

You will never duplicate with a drill and a static engine what happens dynamically when the engine is running.

Run it. I think pull be surprised.

On mine I can usually achieve 70psi with a speed handle/hand tools, with a drill between 70 and 75.
But I have not used a std volume pump since around 1990.
What you have does seem pretty close for what it is.

HV pump will not change the readings. It only give more volume not pressure. barton uses standard pumps on the s/s hemi's.
fire it up and then see what you have.

Or
You can use your brain. If the engine is on the stand, go into the back of the block oil galley on the driver side and block it off. If your pressure goes up it is the lifters bleeding by. We used to block them off all the time and they ran fine. EDM lifters on most engines creates more problems than it solves. You could also just swap out the EDM lifters for regular ones for testing purposes and see what happens. Check the lifter bores for excess clearance while you are it/
Todd

It’s been awhile since I’ve tinkered with big blocks and I never really had an issues but don’t they offer a heavier spring for the oil pumps and haven’t guys shimmed their spring to raise pressure some. I know 440source offers an adjustable one.

I'd swap a HV pump on there and see what happens. My guess is that you have an internal leak so the standard pump just isn't building a lot of pressure. Could be the EDM lifters or it could be something else. This is a good reason to do the prime and oil pressure test before you put the intake manifold on. You could also put a high pressure spring in your standard pump. That may or may not work but it is cheap and easy. If you need more volume then the heavier spring won't fix it but it will fix the problem if your existing spring is softer than normal. For a really cheap and easy solution just slide a couple of washers behind the spring that you have right now and see what happens. A lot of times I'll use a standard spring with a shim or two rather than step up to the heavy spring. I keep a selection of springs and pumps on hand so I can tune the oil pressure on each engine I build. Sometimes I use a standard pump with a heavy spring, sometimes a HV pump with a soft spring. Sometimes some other combination.

More volume into the same restriction will increase the pressure so a HV pump will most likely increase the pressure in his engine. The only time a HV pump wouldn't increase the pressure for the OP's engine is if his current relief spring is set at 40 lbs. That seems unlikely but it could be the case. If he has a HV pump and swaps it on there I bet his pressure goes to 60+ psi.

If the drill is running the pump at 1500 rpm then that is the same as the engine running at 3000 rpm. The pump runs at cam speed or 1/2 of crank speed. In that case, 40 psi at 3000 rpm is pretty low. Having said that, I don't know what speed his drill is actually running at but 40 psi for cold oil is pretty low. I can usually get more than that with a speed wrench.

The drill speed when loaded by oil pressure is nowhere near idle speed, if the drill does not slow down the pump is not engaged or not primed.
I think you're OK but would use 5W40 after a few miles.

I had an adjustable one one one of my pumps that I picked up

I'd get it running and see what pressure it runs at warm (at your intended RPM limit). If you are going to beat on it I like to see 60-70 at 7000. If its low try adding a shim behind the relief valve spring. If that doesn't do it then swap the pump. its no big deal. Idle pressure really doesn't matter.
Doug

I don't have a problem with that advice as long as the pump is easy to get to in his car. If the pump isn't easy to get to in the car then I'd swap to the HV pump now. If it is easy to replace in the car then nothing wrong with running the engine and seeing what it does. Adding a shim won't help if the problem is too little volume. If the internal leaks are bigger than the pump can handle then the bypass could be shimmed shut and it still won't build pressure. So if it is a volume thing due to the EDM lifters he'll need the HV pump. Since nobody knows what the root problem is the OP will just need to experiment.