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Oil pressure how much is needed

Posted By: neonic

Oil pressure how much is needed - 10/15/11 06:00 PM

My new 582 B1 motor only runs 50# and never changes from idle to full throttle. I run a milodon dual line system with milodons pro pump. We run 20-50 Bran Penn oil. How much oil pressure is realy needed under full race conditions.
Posted By: rickraw

Re: Oil pressure how much is needed - 10/15/11 07:26 PM

i was told 10# per 1000 rpm is enough.
Posted By: MR_P_BODY

Re: Oil pressure how much is needed - 10/15/11 10:21 PM

Quote:

My new 582 B1 motor only runs 50# and never changes from idle to full throttle. I run a milodon dual line system with milodons pro pump. We run 20-50 Bran Penn oil. How much oil pressure is realy needed under full race conditions.



Seems strange it doesnt pick up pressure as the revs
goes up...might want to check the by-pass... specially
with that thick of oil.... change the filter also...
this is of course that the gauge is working correctly
Posted By: 68roadrunner

Re: Oil pressure how much is needed - 10/16/11 02:51 AM

i am with mr p on this one. i run 20w50 oil and i see a swing of 80 with rpm to about 40 hot at idle, might check you relief, and all oil filters are not compatible with alcohol.
Posted By: neonic

Re: Oil pressure how much is needed - 10/16/11 02:38 PM

Yes thats what I thought also. i have put a new bypass spring kit in and replaced the gauge. also took the pan off to make sure I was not sticking to the bottom with the pickup. I can shim the spring and gain about 10#. The oil pressure runs the same after doing this no change cold to warm and only about 57# when shimmed. We started out with a milling HV63 pump thought that was the issue so we changed to the milodon pump. Zero change in oil pressuer after doing this. So back to the original question how much oil pressuer is needed on a motor that turns 8000 rpm.

Thanks
Posted By: MR_P_BODY

Re: Oil pressure how much is needed - 10/16/11 02:46 PM

Quote:

Yes thats what I thought also. i have put a new bypass spring kit in and replaced the gauge. also took the pan off to make sure I was not sticking to the bottom with the pickup. I can shim the spring and gain about 10#. The oil pressure runs the same after doing this no change cold to warm and only about 57# when shimmed. We started out with a milling HV63 pump thought that was the issue so we changed to the milodon pump. Zero change in oil pressuer after doing this. So back to the original question how much oil pressuer is needed on a motor that turns 8000 rpm.

Thanks



I would say 70#... like was said already.... the rule
of thumb is 10# per 1000 rpm... but remember that
pressure is a by product of flow vs restriction ...
you want flow to pull heat off... but I still would
be concerned that it doesnt increase with rpm... I
have NEVER seen a engine do what yours is doing
Posted By: mafo

Re: Oil pressure how much is needed - 10/16/11 02:48 PM

in my pump someone had cut the bypass spring, it had only 50 psi or so at 9000, the pump came on my Nickens motor , I didn t feel comfortable with that so now i m running 70 -75
Posted By: neonic

Re: Oil pressure how much is needed - 10/16/11 03:05 PM

Quote:

in my pump someone had cut the bypass spring, it had only 50 psi or so at 9000, the pump came on my Nickens motor , I didn t feel comfortable with that so now i m running 70 -75



i was thinking on the same line when I put a new spring in it. The only thing I have not changed is the bypass plate it self. I guess thats next.
Posted By: MR_P_BODY

Re: Oil pressure how much is needed - 10/16/11 03:12 PM

Quote:

Quote:

in my pump someone had cut the bypass spring, it had only 50 psi or so at 9000, the pump came on my Nickens motor , I didn t feel comfortable with that so now i m running 70 -75



i was thinking on the same line when I put a new spring in it. The only thing I have not changed is the bypass plate it self. I guess thats next.



It sounds like the by-pass isnt closing all the way
and has a weak spring... you added a shim and it went
up slightly... with enough shims it should be able
to blow the filter apart.... are you sure all the plugs
are in the engine... I forgot 1 in the front behind
the timing cover and it did the same thing
Posted By: Al_Alguire

Re: Oil pressure how much is needed - 10/16/11 04:39 PM

FWIW we have 62lbs in the 99 Hemi from idle to 9500, but it is a dry sump system..

Do you have pushrod oiling or tradition oiling to the rockers. What rockers and do you have restrictors?
Posted By: neonic

Re: Oil pressure how much is needed - 10/17/11 03:14 PM

push rod oiling, jesel rockers and comp 892 lifters. The push rods have restrictors and one side of the lifter is blocked off.
Posted By: MR_P_BODY

Re: Oil pressure how much is needed - 10/17/11 03:26 PM

Quote:

push rod oiling, jesel rockers and comp 892 lifters. The push rods have restrictors and one side of the lifter is blocked off.



With my W-5 I just finished up I run TD rockers with
PR oiling and the lifters have a axle feed on the lifters
also and when I was priming it, it had 65# when it
was spinning pretty good and 50# when the drill was
spinning about 300 rpm which would be 600 rpm at the
crank.. this was with 10W30 oil
Posted By: camastomcat

Re: Oil pressure how much is needed - 10/17/11 04:06 PM

Quote:

Yes thats what I thought also. i have put a new bypass spring kit in and replaced the gauge. also took the pan off to make sure I was not sticking to the bottom with the pickup. I can shim the spring and gain about 10#. The oil pressure runs the same after doing this no change cold to warm and only about 57# when shimmed. We started out with a milling HV63 pump thought that was the issue so we changed to the milodon pump. Zero change in oil pressuer after doing this. So back to the original question how much oil pressuer is needed on a motor that turns 8000 rpm.

Thanks




Is it oiled through the pushrods? If so, what size is the lfter bushing hole or pushrod hole? The reason I ask is to know how you are restricting the oil flow to the rockers.
Posted By: camastomcat

Re: Oil pressure how much is needed - 10/17/11 04:08 PM

OK I didn't read the whole post....so the restrictors need to be no more than .060.
Posted By: PorkyPig

Re: Oil pressure how much is needed - 10/17/11 04:16 PM

Quote:

i was told 10# per 1000 rpm is enough.


I've heard 10# per 100 HP, too, from a former NASCAR engine builder who says it the power, not the rpm, you need to account for. Either way, I don't think 50 psi is enough for that engine.
Posted By: neonic

Re: Oil pressure how much is needed - 10/17/11 04:35 PM

Quote:

OK I didn't read the whole post....so the restrictors need to be no more than .060.



The push rod restrictors are .080 would not think this should take a lot of oil pressure off but something is causing it to be lower then it should.
Posted By: MR_P_BODY

Re: Oil pressure how much is needed - 10/17/11 04:46 PM

Quote:

Quote:

OK I didn't read the whole post....so the restrictors need to be no more than .060.



The push rod restrictors are .080 would not think this should take a lot of oil pressure off but something is causing it to be lower then it should.



I went with .040 restriction on my PRs ... I didnt
measure the hole in the lifters that feeds the PR so
I'm not sure if I truly needed to restrict the PRs
or not
Posted By: camastomcat

Re: Oil pressure how much is needed - 10/17/11 04:47 PM

My B1 with pushrod oiling has a .060 oil hole in the bushings (World aluminum block) and makes around 65-70 psi at 7400rpm. It does rise with rpm though. I only really have about 20#'s when the oil is hot at an idle, after a run. So....I can't say for sure that that's your issue, but it couldn't help tha situation and the oil pressure should go up with RPM.
Posted By: polyspheric

Re: Oil pressure how much is needed - 10/17/11 05:32 PM

Gauge pressure isn't what the bearings get, it's only the force with which the pump refreshes the supply to the journal.
The actual local pressure is much higher, and also varies with certain other factors:
1. engine speed
2. journal diameter (actually, circumference)
3. bearing width to the closest leak

1. means local pressure goes up with RPM even if the gauge doesn't move.

2. the relative speeds of the journal and bearing surface in feet/second are what develops the oil wedge, and larger journals have higher local pressure at the same RPM. For a main bearing, it's obvious (3.000" main @ 7,000 RPM = 1,100 f/s, but a rod bearing oscillates while its journal spins so the relative speed changes quite a bit.
This is one reason why low speed truck engines have big journals: good pressure at the bearings at low RPM with low pump pressure.
This is also why it's dangerous to lug small journal motors at low RPM regardless of pump pressure.

3. for a continuous bearing surface this is obvious; however, a groove reduces the pressure to less than 50% vs. an undivided surface.
Math for the closest leak:
width 1.000"
closest leak: 50% = .500"
groove .060"
each half .470"
closest leak: 50% = .235"
Posted By: camastomcat

Re: Oil pressure how much is needed - 10/17/11 05:45 PM

Quote:

Gauge pressure isn't what the bearings get, it's only the force with which the pump refreshes the supply to the journal.
The actual local pressure is much higher, and also varies with certain other factors:
1. engine speed
2. journal diameter (actually, circumference)
3. bearing width to the closest leak

1. means local pressure goes up with RPM even if the gauge doesn't move.

2. the relative speeds of the journal and bearing surface in feet/second are what develops the oil wedge, and larger journals have higher local pressure at the same RPM. For a main bearing, it's obvious (3.000" main @ 7,000 RPM = 1,100 f/s, but a rod bearing oscillates while its journal spins so the relative speed changes quite a bit.
This is one reason why low speed truck engines have big journals: good pressure at the bearings at low RPM with low pump pressure.
This is also why it's dangerous to lug small journal motors at low RPM regardless of pump pressure.

3. for a continuous bearing surface this is obvious; however, a groove reduces the pressure to less than 50% vs. an undivided surface.
Math for the closest leak:
width 1.000"
closest leak: 50% = .500"
groove .060"
each half .470"
closest leak: 50% = .235"




I sort of understand what you are saying, but could you dumb it down a bit? Most on here including me aren't this technically astute.
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