Re: Oil pressure how much is needed
[Re: neonic]
#1094949
10/15/11 06:21 PM
10/15/11 06:21 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
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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
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Re: Oil pressure how much is needed
[Re: neonic]
#1094952
10/16/11 10:46 AM
10/16/11 10:46 AM
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Joined: Jun 2003
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MR_P_BODY
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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
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Re: Oil pressure how much is needed
[Re: neonic]
#1094953
10/16/11 10:48 AM
10/16/11 10:48 AM
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Joined: Feb 2009
Posts: 1,019 Finland
mafo
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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
-65 Valiant,420", all motor,2700#, dot tires, 8,42 @ 160,2
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Re: Oil pressure how much is needed
[Re: mafo]
#1094954
10/16/11 11:05 AM
10/16/11 11:05 AM
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Joined: Jun 2007
Posts: 251 SD USA
neonic
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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.
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Re: Oil pressure how much is needed
[Re: neonic]
#1094955
10/16/11 11:12 AM
10/16/11 11:12 AM
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Posts: 52,972 Romeo MI
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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
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Re: Oil pressure how much is needed
[Re: neonic]
#1094958
10/17/11 11:26 AM
10/17/11 11:26 AM
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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
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Re: Oil pressure how much is needed
[Re: neonic]
#1094959
10/17/11 12:06 PM
10/17/11 12:06 PM
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Joined: Apr 2005
Posts: 2,128 Salt Lake City
camastomcat
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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.
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Re: Oil pressure how much is needed
[Re: rickraw]
#1094961
10/17/11 12:16 PM
10/17/11 12:16 PM
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Joined: Aug 2006
Posts: 610 long time lurker, short time p...
PorkyPig
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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.
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Re: Oil pressure how much is needed
[Re: camastomcat]
#1094962
10/17/11 12:35 PM
10/17/11 12:35 PM
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Posts: 251 SD USA
neonic
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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.
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Re: Oil pressure how much is needed
[Re: neonic]
#1094963
10/17/11 12:46 PM
10/17/11 12:46 PM
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Posts: 52,972 Romeo MI
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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
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Re: Oil pressure how much is needed
[Re: neonic]
#1094965
10/17/11 01:32 PM
10/17/11 01:32 PM
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Posts: 4,206 New York
polyspheric
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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"
Boffin Emeritus
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Re: Oil pressure how much is needed
[Re: polyspheric]
#1094966
10/17/11 01:45 PM
10/17/11 01:45 PM
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Joined: Apr 2005
Posts: 2,128 Salt Lake City
camastomcat
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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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