Oil for boosting oil pressure in 1950s V8

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@ZeeOSix yes and no. I see this argument all over the oil filter part of this forum.

I don't know if people know this, but the oil pump gives 0 f's about PRESSURE unless it's about to go in relief. All it cares is about flowing a set amount at a set rpm regardless of pressure unless it's about to save itself from Going into relief.

Removing any restrictions in the oiling system will make the pressure of the entire system decrease as there is no impediment to flow.

Pressure is nothing but a restriction of flow.

Nobody had a issue and keeps pointing to the bearings. Is the pump flowing the same???? Yes. Are loose bearings essentially a form of increasing flow due to being loose and oil flowing past??? Yes. Can pressure drop due to lose bearings while flow out of the pump being the same??? Yes.

And yes, the oiling mods are significant, especially with that block and THAT PUMP. Unless you screwed one together, then you don't know.

Everything works in theory. In application and different forms of applications, it doesn't always.
 

ZeeOSix

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You are referring to the oil pump, I am referring to the rest of the mods he did to the oiling system after the pump. Pump will try to flow a certain amount at a certain rpm at a certain pressure. If you modify the oiling system enough, that pump will not be able to keep with with the flow.
No, I wasn't referring to the oil pump, but I mention the pump because it's supplying the oil flow volume to the oiling system, and the fact that it's a PD pump matters. The oiling system mods he did helped ensure the pump doesn't hit pressure relief as easily while flowing the same oil volume. Those mods don't make any of the bearings flow more oil, only the bearing clearances effect their flow. As long as supply passages or galleries aren't an extreme choke point on the way to the components needing lubrication, opening them up more isn't going to make bearings flow any more oil. Opening a passage or gallery might reduce the suppy pressure coming out the pump slightly (which also gives more headroom to pressure relief) if it was a choke point, but it's not going to be the kind of oil pressure difference the OP is seeing.

All of the crank, rod and cam journal bearings are still going to be the main contributors of the oil pressure - they are the main "choke points" in the oiling system. Now if there is some reason a whole lot of oil is bypassing the bearings in error, then that's a different situation that could reduce oil pressure, and could also reduce the oil flow through the bearings.

Again, find me one engineer to disagree withe the statement "flow and pressure are inversely proportional" .
In the case of an engine oiling system using a PD pump, that statement is false. You get more pressure when you increase flow when all other factors are held constant. If the flow goes up (higher revs) then the pressure goes up ... that is not an "inverse relationship".

You're thinking of a garden hose with a variable flow nozzel, not an engine oiling system.
 
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No, I wasn't referring to the oil pump, but I mention the pump because it's supplying the oil flow volume to the oiling system, and the fact that it's a PD pump matters. The oiling system mods he did helped ensure the pump doesn't hit pressure relief as easily while flowing the same oil volume. Those mods don't make any of the bearings flow more oil, only the bearing clearances effect their flow. As long as a supply passages or galleries aren't an extreme choke point, opening them up more isn't going to make bearings flow any more oil. Opening a passage or gallery might reduce the suppy pressure slightly if it was a choke point, but it's not going to be the kind of oil pressure difference the OP is seeing.

All of the crank, rod and cam journal bearings are still going to be the main contributors of the oil pressure - they are the main "choke points" in the oiling system. Now if there is some reason a whole lot of oil is bypassing the bearings in error, then that's a different situation that could reduce oil pressure, and could also reduce the oil flow through the bearings.


In the case of an engine oiling system using a PD pump, that statement is false. You get more pressure when you increase flow when all other factors are held constant. If the flow goes up (higher revs) then the pressure goes up ... that is not an "inverse relationship".

You're thinking of a garden hose with a variable flow nozzel, not an engine oiling system.
Except he did increase flow through the bearings by opening up the holes in them. He furthermore enhanced flow by the other mods he did. He is having his bulk of issues at idle. Low rpm, low flow, low pressure. The mods he did make a SIGNIFICANT difference on a FE. I helped build a few for cobras. We did these mods. We had these issues.

Op, we also had issues with oil pumps from different manufacturers. Everything from the flange being machined at an angle losing seal to incorrect springs, to the pumps leaking at the plates, to loose rotors inside the pump.

Tbh, I'd pull the pump and put in a hv pump.
 

ZeeOSix

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Except he did increase flow through the bearings by opening up the holes in them.
The bearing's clearance is what controls the flow, not the big hole that supplies oil to the bearing. I highly doubt the stock holes were choking supply because those stock holes can flow way more than the bearing can. Especially at an idle.

He furthermore enhanced flow by the other mods he did. He is having his bulk of issues at idle. Low rpm, low flow, low pressure. The mods he did make a SIGNIFICANT difference on a FE. I helped build a few for cobras. We did these mods. We had these issues.

Op, we also had issues with oil pumps from different manufacturers. Everything from the flange being machined at an angle losing seal to incorrect springs, to the pumps leaking at the plates, to loose rotors inside the pump.

Tbh, I'd pull the pump and put in a hv pump.
I still think there's some other inherent issue(s) going on besides opening up a few flow passages.

I asked what the rod bearing clearances were, so let's see what that response is. What about the push rods? Did he put some aftermarket push rods in that have much larger oil holes in the rod ends that is sending too much oil to the heads?
 
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In the case of an engine oiling system using a PD pump, that statement is false. You get more pressure when you increase flow when all other factors are held constant. If the flow goes up (higher revs) then the pressure goes up ... that is not an "inverse relationship".

You're thinking of a garden hose with a variable flow nozzel, not an engine oiling system.
Absolutely not thinking garden hose here.

Yes, when you Rev the engine flow goes up. Pump is spinning faster, it's flowing more oil. It's flowing that oil into a RESTRICTION, the entire oiling system. PSI only goes up due to the impedance to that flow. Anything that removes a restriction to that will cause pressure to drop but the flow of the pump will remain the same or even go up. Lose bearings, oiling mods, etc.

Once again, with the oiling mods he has done, it IS a inverse relationship between flow and pressure.

Answer this. If you have loosey goosey bearings in the engine, is that pump flowing the same volume and pressure at a specific rpm vs a engine with the correct clearances at the same rpm???? Yes or no.
 
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Once again, the mods he did are SIGNIFICANT to an FE. Open one up and look at the main bearings. You'd swear you have the incorrect bearings or they were trying to restrict flow to them by covering half the hole in the block. Or it's that quality casting Ford always offered.

How these things ran without spinning bearings is beyond me. Don't get me started on the cam bearings.

They should have been known as the Subarus of the 50s and 60s.
 

ZeeOSix

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Absolutely not thinking garden hose here.
Your flow and pressure "inverse relationship" doesn't apply to an engine oiling system. Give me an example in a fixed configuration engine oiling system when the oil flow goes down when the oil pressure goes up without changing the flow resistance. There is no such situation. In post #62 I clarified with the statement of "when all other factors are held constant", and that includes the overall flow resistance of the oiling system.

Yes, when you Rev the engine flow goes up. Pump is spinning faster, it's flowing more oil. It's flowing that oil into a RESTRICTION, the entire oiling system. PSI only goes up due to the impedance to that flow. Anything that removes a restriction to that will cause pressure to drop but the flow of the pump will remain the same or even go up. Lose bearings, oiling mods, etc.
Now your putting caveats on your flow and pressure "inverse relationship" statement. You didnt make that caveat earlier. You simply said pressure and flow are "inversely proportional", which is not true in a fixed system.

Once again, with the oiling mods he has done, it IS a inverse relationship between flow and pressure.
Answer this. If you have loosey goosey bearings in the engine, is that pump flowing the same volume and pressure at a specific rpm vs a engine with the correct clearances at the same rpm???? Yes or no.
See last reponse. You need to be more clear before blurting out a statement of: "flow and pressure are inversely proportional" without details. The statement as it stands is false in a fixed configuration (flow resistance) oiling system.
 
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ZeeOSix

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BTW, low oil pressure doesn't necessarily mean a lack of oil flow and lubrication to the engine components supplied by the pump. Only component abnormal wear or failure will tell that - but that's the last way you want to find out, lol.
 
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Fabulous50s

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The bearing's clearance is what controls the flow, not the big hole that supplies oil to the bearing. I highly doubt the stock holes were choking supply because those stock holes can flow way more than the bearing can. Especially at an idle.


I still think there's some other inherent issue(s) going on besides opening up a few flow passages.

I asked what the rod bearing clearances were, so let's see what that response is. What about the push rods? Did he put some aftermarket push rods in that have much larger oil holes in the rod ends that is sending too much oil to the heads?
Push rods are stock FE which don't flow oil. Oil is fed to the hyd lifters, and to the rocker shafts.

Everything is stock/NOS accept Silvolite pistons, and the Melling standard volume oil pump.

I actually didn't write down what my rod bearing clearances were, I measure with a micrometer and a bore gauge to calculate bearing clearance. Double check with plastigauge on a bearing or two.

I'm going to pull a valve cover and see if it's over oiling/flooding the rocker shafts.

I'm not going to keep reanswering the same questions about known oil pressure. Please read my posts. I wouldn't be posting it here if I hadn't confirmed I do indeed have low oil pressure.
 

ZeeOSix

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I'm not going to keep reanswering the same questions about known oil pressure. Please read my posts. I wouldn't be posting it here if I hadn't confirmed I do indeed have low oil pressure.
I don't doubt that you have low oil pressure as reported, and seems nobody else doesn't believe it either. Just like everyone else, only trying to give possible reasons why.
 

ZeeOSix

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I'm going to pull a valve cover and see if it's over oiling/flooding the rocker shafts.
Oil flow to the valve train shouldn't have changed unless you did some kind of mod that opens up the flow path from the main oil gallery to the heads.
 

Fabulous50s

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Oil flow to the valve train shouldn't have changed unless you did some kind of mod that opens up the flow path from the main oil gallery to the heads.
I didn't do anything to any oil passages to valvetrain.

Everyone is correct, the small mods I did only opened up oil passages to the bearings. So shouldn't have any effects on oil pressure. I'm tempted to remove the pump and inspect it. They are cheap, and I may just put another in.
 

ZeeOSix

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I didn't do anything to any oil passages to valvetrain.

Everyone is correct, the small mods I did only opened up oil passages to the bearings. So shouldn't have any effects on oil pressure. I'm tempted to remove the pump and inspect it. They are cheap, and I may just put another in.
As someone mentioned earlier, how confident are you that the pressure gauge is reading accurately? Might be worth putting a good known mechanical pressure gauge on the main gallery for another check if you have a port to do so. Or figure a way to check the accuracy of the current pressure gauge.
 
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Flow does lubricate, not pressure. Of course, flow it proportional to pressure when all other factors are held constant.
Yes but what I meant was that if the flow is sufficient to supply the bearings with adequate lubricant then increasing the flow will not lubricate more better.

I guess I just get tired of people thinking flow is always the problem and more flow fixes everything.
 
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I just picked up 2x 5qt Jugs of M1 15w-50. I didn't know M1 still made it. I used to run M1 15w-50 in my VWs.

5. Relieve the oil holes in the main bearings to better line up with the offset oiling holes in the block. I didn't touch the block, just the bearings.
Lets us know how that 15w50 works. The only other recommendation I'd make prior to replacing the pump, is the NapaPlatinum/WixXP oil filter. I've had issues with some wix products and won't use the Napa gold/silver or Wix regular filters anymore.

BTW, V-rod 10w30 is 3.6 HTHS and almost ~12cst new. Didn't notice that. Skip the 40 grades and go straight to that 15w50. Not that I blindly believe in spec sheets, but would wager the vrod as a pretty thick/stout oil from Amsoil. The Mobil1 15w50 and Vtwin 20w50 would be my new starting points.

I also don't think Melling is as good as they used to be. Could've just got a bad pump. So, if the 15w50 doesn't get you what you want for PSI, its time to lift the motor for the bigger HV oil pump if you want the PSI. Otherwise, I'd just run the engine as is... since its not a race car. Swapping the pump is easier than stripping the engine down and re-rebuilding it to make sure some measurement wasn't skipped.

5. That offset might've been the equivalent of oil flow balancing restrictors. God only knows why Ford, on some engines, dumps way too much flow on certain bearings and starves the rest of the engine. And, why can't the bearing manufacturer or Ford, make half of their bearing ports not line up too well at all. That relief might be flowing too much oil, leaking too much oil, and dropping your PSI. Flow increase is needed so get the HV pump. I'd wager your pressure is low because you're leaking too much past too many bearings. You're just not stacking up against the flow to build pressure. Worse case scenario... something is being starved. Someone else used the word 'leaking' and why I posted that youtube video earlier hoping no missing plugs and a 'oh shoot' scenario. Maybe the clearances aren't as tight as you've measured? Engine isn't a perfect world so armchair bandits arguing flow/pressure inversely means nothing if there is a leak or numerous small leaks internally. On my 351c/351m/400, had to starve the big leak by running an oil hose from the front to the back of the engine, a oil flow/pressure balancing act, and always planned, at the next rebuild, some oil flow restrictors to balance flow. Some ran pretty much forever on 10w40 even with the occasional low PSI flicker from the dash light. One went from 5w30, to 10w40, and then to 20w50 over 300k miles before finally knocking. I myself wouldn't want a 'refreshed' engine that needs 20w50 from the start for idle psi. Obviously, if its not in a daily driver that is pulling a trailer, then one could be happy with the PSI and not worry about it.

Its pitiful that your thread turned into chest thumbing armchair wannabe engineers battling it out. Same ol' same ol' in every thread.

Did I miss the vehicle model? and its pictures?
 
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Your flow and pressure "inverse relationship" doesn't apply to an engine oiling system. Give me an example in a fixed configuration engine oiling system when the oil flow goes down when the oil pressure goes up without changing the flow resistance. There is no such situation. In post #62 I clarified with the statement of "when all other factors are held constant", and that includes the overall flow resistance of the oiling system.


Now your putting caveats on your flow and pressure "inverse relationship" statement. You didnt make that caveat earlier. You simply said pressure and flow are "inversely proportional", which is not true in a fixed system.


See last reponse. You need to be more clear before blurting out a statement of: "flow and pressure are inversely proportional" without details. The statement as it stands is false in a fixed configuration (flow resistance) oiling system.
No sir. Not putting caveats on anything. Just responding to threads on a case by case situation, not a global one. I should have clarified that. That, I'm not going to argue.

I think we just spent 1 hrs arguing about agreeing to an extent.
 
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"Flow and pressure are inversely proportional"... This applies when you have a fixed volume with varying restriction. It does not apply when you have fixed restriction with varying volume. Since the engine's restrictions are fixed and volume is varying with rpm, it becomes more complicated than that. Throw in factors like viscosity and aeration, it becomes even more complicated. The only time that statement is applicable is comparing the same volume at the same idle rpm with the same viscosity, temperature, and other conditions.

After coming full circle over this matter, I still stand by the statement that 10 psi of oil pressure at hot idle is itself not concerning. It's likely double what the engine actually needs at hot idle. Opening the bearing holes to match the block holes likely did increase flow into the bearings and reduce pressure some. Depending on the bearing brand, those holes can be quite restrictive.

I think the OP is wasting perfectly good Z-Rod 10W-30 oil and wasting money on a 15W-50 in an attempt to fix something that isn't a problem. The 15W-50 is meant for engines with twice the clearance he has. (and 2-3x the power) I expect with the tighter clearance, the engine will see high hydrodynamic friction and the bearing getting much hotter than it should. Since this is a low rpm cruiser, it likely won't be an issue, and will just rob a little fuel economy. I do worry a little about the oil wedge in the bearings on cold starts as that 15W-50 is likely 400-600 cSt at 50-60°F trying to squeeze through a .0018" bearing. Imagine it down at 32°F. It'll put more strain on the starter trying to crank it over in that molasses.
 
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I also don't think Melling is as good as they used to be. Could've just got a bad pump. So, if the 15w50 doesn't get you what you want for PSI, its time to lift the motor for the bigger HV oil pump if you want the PSI. Otherwise, I'd just run the engine as is... since its not a race car. Swapping the pump is easier than stripping the engine down and re-rebuilding it to make sure some measurement wasn't skipped.

5. That offset might've been the equivalent of oil flow balancing restrictors. God only knows why Ford, on some engines, dumps way too much flow on certain bearings and starves the rest of the engine. And, why can't the bearing manufacturer or Ford, make half of their bearing ports not line up too well at all. That relief might be flowing too much oil, leaking too much oil, and dropping your PSI. Flow increase is needed so get the HV pump. I'd wager your pressure is low because you're leaking too much past too many bearings. You're just not stacking up against the flow to build pressure. Worse case scenario... something is being starved. Someone else used the word 'leaking' and why I posted that youtube video earlier hoping no missing plugs and a 'oh shoot' scenario. Maybe the clearances aren't as tight as you've measured? Engine isn't a perfect world so armchair bandits arguing flow/pressure inversely means nothing if there is a leak or numerous small leaks internally. On my 351c/351m/400, had to starve the big leak by running an oil hose from the front to the back of the engine, a oil flow/pressure balancing act, and always planned, at the next rebuild, some oil flow restrictors to balance flow.

Its pitiful that your thread turned into chest thumbing armchair wannabe engineers battling it out. Same ol' same ol' in every thread.

Did I miss the vehicle model? and its pictures?
This is pretty much what I said a few posts back when I questioned the quality of Melling as of lately and the bearings covering half the oiling hole.

People are not familiar with Fords and the oil modifications needed when rebuilding past factory. So many oiling mods you can do to....well....any of Ford pushrod engines to make them way better than factory.

I do have to disagree with the arm chair warrior comment. Nobody was way off base with their comments. IMHO, it just goes to highlight the difference platforms people are familiar with and the different issues as well as fixes.

The discourse in this thread was quite civil and informative. I learned stuff, maybe op learned stuff. One of the better threads.

BTW and OT....those Cleveland you mentioned, IMHO they're the best pushrod engines anyone built.
 
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