Low oil pressure?

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Brian, I had forgotten about Jab, I'd had him on "ignore" cuz of his bs.

Now I've had an evening of ROFL, he's going back to "Iggy".

Try it, your blood pressure will go down, you'll like it.
Best part - his b/pressure goes up. ROFL.
Enjoy.
 
and back when there were no oil filters, then bypass
remember the Frantz, toilet paper filter and JC Whitney's version
the in and out of the fiilter are close to balanced- hydraulic pressure wise no flow there once the filter fills up without a plug- just no filtration
 
O.K. I think you guys are thinking it all wrong,
1) You have a oil pump pumping oil, it will not make pressure till it hits a dead end, and that is the bearings. If you change your oil and filter and start the engine there is no pressure till the filter fills up the oil is pushed through the engine and hits the bearings, now it has pressure.
2) You are talking about the filter draining back, oil looping in and out of the filter and this is impossible without a hole back to the pan, the pump wont stop pumping oil even if there is no pressure and it will fill the engine galleys and it will hit the bearings at the end of the line. Then and only then will it drain back in the pan to get picked up again.
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If you think there's no oil pressure until the oil hits the bearings you are just so wrong.
The only reason I put a red X on there is because I disagree with you.

fluid pressure. noun. the pressure exerted by a fluid at any point inside it. The difference of pressure between two levels is determined by the product of the difference of height, the density, and the acceleration of free fall.

Every turn of the passage every downsize of the passage causes resistance which builds pressure. If it comes to an open area then the pressure drops.
How about we get back to solving this guy's problem instead of discussing this plug.
 
We are trying to solve the problem. One side says that the removed/dislodged plug in question will lose all or most pressure like the book says. Other side says it’s bs because without the plug, you’d lose most/all filtration and actually gain a small amount of pressure at the sending unit location.
 
The oil does not drain back through the oil pump and pickup on a small block. Anyone who has used an accumulator can verify that as the accumulator would not work if that were possible.
The two passages leading to and from the filter are both horizontal
With each other. The plug is located precisely in between these two passages. Therefore there is pressurized oil on both sides of the plug.
If the plug is gone, then oil on the supply side to the main gallery can drain back past the filter through the passage. There is nothing to stop it from draining downward and leaving the pump and pickup 'dry' with no plug.

If you are referring to an accumulator having a cold start oil supply, that is done with a ball valve to store the pressurized oil when not running; in that state, the accumulator is essentially disconnected from the oiling system so has nothing to do with drainback, with or without the plug.

If you are referring to an accumulator working while the engine is running, then the oil from the accumulator should be blocked from flow back to the pump and pan by the filter's check valve (which is a simple rubber disc). If the plug was not there, then indeed the oil could flow back TO the pump gears as well as into the main passages from the accumulator; but the still spinning pump gears would keep it from going further, to the pan.

So the accumulator operation does not prove anything about drainback, or not, that I can see (expect that the filter's check valve is part of it working); if you see a point in the above that is wrong, then please make it clear where I am off-track. And, none of that is the normal drainback problem to which I was referring with the plug missing and the engine not running.

Yes, agreed on the passages, and pressurized oil on both sides. Not sure what you are trying to say; the pressures are different on each side of the plug due to drop in the filter element.

If anyone familiar with hydraulics wants to demonstrate that oil will flows in a circular path with the plug gone, then please do so on the basis of relative pressures at specific points. And if you want to challenge my numbers and my view of pressures at various points, please feel free do so.
 
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If you think there's no oil pressure until the oil hits the bearings you are just so wrong.
The only reason I put a red X on there is because I disagree with you.

fluid pressure. noun. the pressure exerted by a fluid at any point inside it. The difference of pressure between two levels is determined by the product of the difference of height, the density, and the acceleration of free fall.

Every turn of the passage every downsize of the passage causes resistance which builds pressure. If it comes to an open area then the pressure drops.
How about we get back to solving this guy's problem instead of discussing this plug.

This is an old post May 22 so I think his problem has already been fixed, you started something so finish it show me that I am wrong,

Cope did you find the problem ? I didn't read the entire post so I don't know.

I know that when I start my truck after a oil change the gauge sits on 0psi and all of a sudden shoots to 60psi, now I am sure that there is a little pressure as the oil is being pushed through the engine and as everything fills up it's not enough to move the gauge. Now when the engine is shut off with out the plug the oil will drain back to the pan emptying the engine, but with a wet oil pump the oil will pick up on start up and build to full pressure even with the plug out and bypassing the filter..
 
I never did find the problem
The engine just need to last till the winter and its gonna be pulled and torn down for inspection any way.
So I figure I can deal with it till then.

I did find something much more scary today tho, check out my latest post!
 
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I accept what Chrysler has been saying for the last 50 years or more and they still say it in their hot rod books written by Engineers for Chrysler.
You evidently subconsciously accept it or you'd be leaving those plugs out of there from time to time anyway.
I'm sorry that the red X's upset you so much. Maybe someday you'll understand that not everybody agrees with everything you say.
 
Cope if you have the valve covers off that motor post a picture of the rocker arm assembly.
 
I never did find the problem
The engine just need to last till the winter and its gonna be pulled and torn down for inspection any way.
So I figure I can deal with it till then.

I did find something much more scary today tho, check out my latest post!
Not sure if this was suggested earlier in the thread and I know everyone does not agree, but you could unthread your oil pressure sending unit and stick a coat hanger or something down the hole and at a certain depth you should hit something solid if the plug is in there. The plug is inline with the oil pressure sending unit hole.
Many years ago I missed the drivers side galley plug, that would make pressure very low too and noisy lifters.
 
If the plug is gone, then oil on the supply side to the main gallery can drain back past the filter through the passage. There is nothing to stop it from draining downward and leaving the pump and pickup 'dry' with no plug.

If you are referring to an accumulator having a cold start oil supply, that is done with a ball valve to store the pressurized oil when not running; in that state, the accumulator is essentially disconnected from the oiling system so has nothing to do with drainback, with or without the plug.

If you are referring to an accumulator working while the engine is running, then the oil from the accumulator should be blocked from flow back to the pump and pan by the filter's check valve (which is a simple rubber disc). If the plug was not there, then indeed the oil could flow back TO the pump gears as well as into the main passages from the accumulator; but the still spinning pump gears would keep it from going further, to the pan.

So the accumulator operation does not prove anything about drainback, or not, that I can see (expect that the filter's check valve is part of it working); if you see a point in the above that is wrong, then please make it clear where I am off-track. And, none of that is the normal drainback problem to which I was referring with the plug missing and the engine not running.

Yes, agreed on the passages, and pressurized oil on both sides. Not sure what you are trying to say; the pressures are different on each side of the plug due to drop in the filter element.

If anyone familiar with hydraulics wants to demonstrate that oil will flows in a circular path with the plug gone, then please do so on the basis of relative pressures at specific points. And if you want to challenge my numbers and my view of pressures at various points, please feel free do so.

I was referring to the operation of the accumulator when the ball valve is opened with the engine not running or when pre oiling.
Canton explains in the instructions that some engines because of the way the oil pump is designed will allow the accumulator oil flow to go out through the pump and not to the engine. They recommend an inline check ball be placed in the engine outlet line side to force the direction of the accumulator oil into the engine. Much like the plug.
The small block Mopar oil pump apparently does not have this problem at least from a pre oil perspective. But I suppose if the engine sat unused for an extended period that some drain back would happen.
Regarding the pressure on both sides, the plug sits on a step in the bore, I agree that high pressure would not move the plug in the direction of the step, but the pressure on the supply side could maybe, potentially blow the plug out the other way because there is no step on the other side. I believe imho that this does not happen because after the engine builds oil pressure, the pressure on both sides of the plug are equal so it does not come out.
Hope that explains it better.
 
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I accept what Chrysler has been saying for the last 50 years or more and they still say it in their hot rod books written by Engineers for Chrysler.
You evidently subconsciously accept it or you'd be leaving those plugs out of there from time to time anyway.
I'm sorry that the red X's upset you so much. Maybe someday you'll understand that not everybody agrees with everything you say.

It's not that at all. It's that you have told everyone on this post they don't know what they are talking about and you are a man right ? So you owe them and me a apology or prove us wrong, That is all. Do the right thing.
 
It's not that at all. It's that you have told everyone on this post they don't know what they are talking about and you are a man right ? So you owe them and me a apology or prove us wrong, That is all. Do the right thing.
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Okay I apologize for not agreeing with you because you can't accept what Chrysler has been trying to tell you for the last 50 plus years.
 
I was referring to the operation of the accumulator when the ball valve is opened with the engine not running or when pre oiling.
Canton explains in the instructions that some engines because of the way the oil pump is designed will allow the accumulator oil flow to go out through the pump and not to the engine. They recommend an inline check ball be placed in the engine outlet line side to force the direction of the accumulator oil into the engine. Much like the plug.
The small block Mopar oil pump apparently does not have this problem at least from a pre oil perspective. But I suppose if the engine sat unused for an extended period that some drain back would happen.
Regarding the pressure on both sides, the plug sits on a step in the bore, I agree that high pressure would not move the plug in the direction of the step, but the pressure on the supply side could maybe, potentially blow the plug out the other way because there is no step on the other side. I believe imho that this does not happen because after the engine builds oil pressure, the pressure on both sides of the plug are equal so it does not come out.
Hope that explains it better.
Thanks for the thorough post; it is much appreciated. (No red X's LOL)

Just to add to this:
- Understood on the accumulator operation. The SBM pump looks like it would stop reverse flow to just slow leakage when sitting still based on how it operates. But indeed Mopar has used anti-drainback filters for decades just to limit the slow drainback when the engine is off. (They also used tall standtubes on the /6 filter base for the same reason: it limits the filter drainback problems. ) It's that feature that would get lost with the plug missing and might be the cause of the issues mentioned in your book.
- Look at the passages top and bottom on either side of the plug and realize that the upper one is after the filter. Whatever filter pressure loss occurs in the filter will make the upper passage's pressure lower than the lower passage's pressure. So there always will be a pressure difference, with the higher pressure being underneath the plug, before the filter. The difference may be very slight with a new filter and thin oil and idling speeds, but the pressure difference will always be such as to push the plug upwards. I would imagine that was the reason to put that step in a certain way.
- Leaving out the driver's side gallery plug is a whole 'nother animal and will indeed cause serious pressure loss; this issue keeps popping up from time to time here. Its place in the oiling chain is quite different, so can't be used to judge what would happen if the 'filter bypass' plug is left out.
 
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Every turn of the passage every downsize of the passage causes resistance which builds pressure. If it comes to an open area then the pressure drops.
Jada, I'm seriously not picking on you. But if I am reading the above correctly (and I may not be), that is an incorrect view on pressure changes through a flow path. Pressure always drops as one measures along a flow path; it never goes up. (Seriously, honest-to-goodness, cross-my-heart-and-hope-to-die, etc.) The only way it can increase is if there is an active device in the flow path (a pump) or a resonant effect in the flow (like the 'water-hammer' problem in water piping systems). The pressure drop after a restriction is correct (like in the lower part of a carb throat), and everything in this oiling path is a restriction to some degree or another; the filter, each and every passage, etc.

And logically, you can convince yourself this is so. If the pressure went up anywhere in the system, then the flow would have to reverse. Hmmmm... maybe this is what is causing the idea of oil flowing around back through the filter?

I just want to be sure there are no misconceptions contributing to this situation.
 
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Okay I apologize for not agreeing with you because you can't accept what Chrysler has been trying to tell you for the last 50 plus years.

I'm not telling you to disagree, I trying to get you to see the big picture, the book is wrong and has been printed over and over and nobody changed it, so forget the book and look at the diagram. Your not a dumb guy but you refuse to acknowledge the book is wrong.

Take the filter off and put a U pipe there the oil still goes through the engine, take the plug out and plug the 2 holes going to the filter, the oil goes through the engine, pretty simple.

360 OIL FLOW DIAGRAM.jpg


2719.jpg
 
The resistance thing is not trivial which is why we bore out the oil passages but this is more for flow than for pressure
every plumber knows about curves, tight elbows and wall friction
however in comparison to a plug it is trivial jad
for all PRACTICAL purposes the other guys have it more useful
your point is well taken however
 
The resistance thing is not trivial which is why we bore out the oil passages but this is more for flow than for pressure
every plumber knows about curves, tight elbows and wall friction
however in comparison to a plug it is trivial jad
for all PRACTICAL purposes the other guys have it more useful
your point is well taken however
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I won't Red X you however I don't agree with everything you're saying. LOL
I have a great idea for how to answer this question. That is at the Larry Shepherd seminar at the Nationals on Saturday someone asked him about leaving the plug out. And that should give us the answer we've all been waiting for.

Meet Butch Leal at the HDK Tent, signing autographs along with the debut of his 1975 B/MP Duster. Larry Shepard Tech Seminar - In celebration of the 50th Anniversary of the 340 Small Block debut in 1968, Larry has prepared some Tips & Tricks for the owner along with a Q&A. The Seminar takes place on Saturday at 1:00PM at the Nats Seminar/Match Box Race Tent located just behind the large Green Mopar Pavillion.
Unfortunately I won't be there so I can't ask him but surely someone here will be there and can do it.
 
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Just a FYI, Larry Shepard that wrote the book has long passed your talking about Larry Shepard Jr. and he will never be as smart as his dad. I have talked to him many times, he lives about 10 miles from me.
 
Just a FYI, Larry Shepard that wrote the book has long passed your talking about Larry Shepard Jr. and he will never be as smart as his dad. I have talked to him many times, he lives about 10 miles from me.
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During any of those conversations did you ask him about the plug?
 
No never came up, really only talked about BB's and Hemi's. I built a Hemi for a guy about 6 years ago and we talked quite a bit on it.
 
Jada, I'm seriously not picking on you. But if I am reading the above correctly (and I may not be), that is an incorrect view on pressure changes through a flow path. Pressure always drops as one measures along a flow path; it never goes up. (Seriously, honest-to-goodness, cross-my-heart-and-hope-to-die, etc.) The only way it can increase is if there is an active device in the flow path (a pump) or a resonant effect in the flow (like the 'water-hammer' problem in water piping systems). The pressure drop after a restriction is correct (like in the lower part of a carb throat), and everything in this oiling path is a restriction to some degree or another; the filter, each and every passage, etc.

And logically, you can convince yourself this is so. If the pressure went up anywhere in the system, then the flow would have to reverse. Hmmmm... maybe this is what is causing the idea of oil flowing around back through the filter?

I just want to be sure there are no misconceptions contributing to this situation.
I am not trying to be sarcastic here but a few years ago I overhauled my 47re in my Dodge Ram truck. On the valve body there is a valve called a boost valve. I have a full time oil pressure gauge on my trans. The line pressure runs about 90-100 lbs. when the torque converter locks up when that valve kicks in the pressure goes up to 130 lbs even though the line pressure is 90-100. I do not understand how that works.
 
I'm not telling you to disagree, I trying to get you to see the big picture, the book is wrong and has been printed over and over and nobody changed it, so forget the book and look at the diagram. Your not a dumb guy but you refuse to acknowledge the book is wrong.

Take the filter off and put a U pipe there the oil still goes through the engine, take the plug out and plug the 2 holes going to the filter, the oil goes through the engine, pretty simple.

View attachment 1715207965

View attachment 1715207967
Here is an example that maybe will shed some light.
A friend of mine build a new home and had his water pipes plumbed in a circular loop from the water heater.
The idea was that even though no water faucets are open and using water, the water is able to continually flow through the water heater and around the house to keep hot water readily available.
This way when you opened the tap to get hot water there was not a long delay for the hot water to get to the faucet. The system is closed but it is looping under pressure.
 
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