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Old 04-07-2020, 05:06   #91
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Re: Another Low Oil Pressure Query

Quote:
Originally Posted by Scubaseas View Post
I'll take your word for it that you believe you can have a downstream pressure higher than the regulated line pressure.



Oil for a 2003 Jeep 4L is 10W30 that meets Chrysler MS6395, 5w30 in cold climates. Use the specified oil of the right viscosity and you'll have little if any sludge build up. Especially if the vehicle gets relatively short drive cycles, like under 30 minutes. Use the right oil and you won't have problems in the first place. This is hypercritical in automotive applications post around 2000.



Lowering the design operating temperature can lead to oil being too cold (which has it's own issues), the emissions not working right and water condensate/sludge build up inside the engine. I would bet the engineers at Chrysler may know more about it than anyone.
Got nothing to do with what I 'believe'...

Having trouble seeing what's so hard to grasp about this, so it must have something to do with my explanatory powers. I'll give it one more go, as much to improve whatever of those powers I might have as in hope that I can make it clear to you how the lubrication system in question appears to be designed to operate. Without having access to either the designer or the system itself, this is of course all hypothesis, but with the already supplied information from the manufacturer, chances are very good that these hypothoses are correct.

Using the diagram supplied by the manufacturer below, starting from the left, the oil is pulled through the first 'filter', the pickup screen, by the positive displacement oil pump.

At about 43 psi, the first pressure 'regulator' valve is fully open, dumping (relieving) a volume of oil, set by the size of the orifice and the pump rpm, at 'X' amount.

The remaining volume of oil, again variable due to pump rpm, is sent, in respective order, to the oil filter, the oil cooler, the second regulating valve (where it is regulated again, this time to between about 50-65 psi) and turbo if fitted, and from there to the various lubrication, cooling or monitoring locations.

The miscomprehension seems to be in the function of the first valve and the relation of volume to pressure. Perhaps it'll help to think of it in a different system. Imagine a big-ass screw compressor (the oil pump) filling a 100 gallon air tank (the lube system) with a half inch hole in it (the fully open 43 psi 'regulator' valve). You can still run all the tools in the shop at 100 psi because the volume supplied by the compressor pressurizes the system faster than the hole in the tank can reduce the pressure.

At this point the metaphor starts to fall apart; I think Bernoulli might start to come into play, but for our purposes it should explain the 'pressure conundrum' well enough.

It does seem to reopen the 'what's the real use of the first valve?' question though, but as previously explained (I think), that can be attributed to the desire to have sufficent flow at initial startup and low rpm.


Your opinions on what theoretically should happen when using factory
approved and recommended oils do not, in this case at least, reflect reality.

As noted, when I got the vehicle, it had been shop maintained, with records, for 183,000 miles. It was obvious when I got it that there were heavy deposits on the interior upper portions of the engine; almost certainly these are the result of a designed 210F engine operating temperature and the resultant extremely high engine compartment temperatures.

I'm well aware of the potential repercussions of lowering the operating temperatures, which is why I said I'd 'play' with different tstats. I hope to be able to use a 195 or so and still keep the emission systems operating well enough.

Certainly Chrysler engineers know more about it than most anyone, but their ideas of initial efficiency and my ideas of ultimate efficiency probably don't align very well...
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Old 04-07-2020, 10:35   #92
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Re: Another Low Oil Pressure Query

My apologies to wingsail, the OP for drift. I promise this will be the last entry by me on this topic unless asked. I had hoped a cordial conversation could have been had in regards to the function of a seemingly duplicate valve, as in what exactly is the function of the second valve to regulate pressure or (now) volume. I will apologize again to Mr. Bunyard for offending him is some fashion and to the forum for my poor command of written English or my writing style.

I agree with jimbunyard for the most part excepting perhaps the following quotes which are not exhaustive.
Quote:
I fear your use and understanding of written English is about on par with your mechanical knowledge. Not sure what my right has to do with anything, but if you mean my being right, that has nothing at all to do with it. The OP is asking questions about things he has less information about than others have. It's important to give the most accurate information possible to ensure the most complete understanding in the shortest amount of time. Inaccurate or incomplete information is at best confusing and a waste of time.
And off we go! Sorry, maybe it's a cultural thing but I do not consider the above statement to be warm and fuzzy. Apparently Mr.Bunyard's umbrage is in response to me disagreeing with him. Which I apologized for and will do so again. I get he is right and everyone else is wrong but apparently me more than anything or anyone else.

Quote:
So there (sic)
Really?

Quote:
Why? Believe Pascal's principle has to do with pressure in a closed system, which an engine's lubrication system is not.
Pascal applies up to the moment you crack open the pressure, volume, regulation or relief valve or whatever it's now called. But somehow you get an extra 21.4 PSI. I will concede it may simply be that I can not understand English and all of this nonsense is entirely my fault.

Quote:
The miscomprehension seems to be in the function of the first valve and the relation of volume to pressure. Perhaps it'll help to think of it in a different system. Imagine a big-ass screw compressor (the oil pump) filling a 100 gallon air tank (the lube system) with a half inch hole in it (the fully open 43 psi 'regulator' valve). You can still run all the tools in the shop at 100 psi because the volume supplied by the compressor pressurizes the system faster than the hole in the tank can reduce the pressure.
I couldn't agree more. I do not see how you can run the tools at 125PSI however.

Quote:
Maybe the valves are rated on different scales, perhaps working vs static pressure.
I doubt this.

Quote:
Since I've no official "bona fides" (are you one of the Coens in disguise?) other than designing, building and repairing all things mechanical for as long as I can remember (and according to people who should know [parents and siblings] since before I can remember [about 9 or 10]), perhaps you can decide which of the three seems more likely, or can provide the real answer.
The real answer is you can't explain it given what you have said up to this point in time. It was a rhetorical question.

Quote:
At this point the metaphor starts to fall apart; I think Bernoulli might start to come into play, but for our purposes it should explain the 'pressure conundrum' well enough.
It does not explain it and it's analogical reasoning you are using. Bernoulli does not come into play here. The expression you may be looking for is Volumetric Flow Rate.

I understand you may never be wrong but in this case you may not be so much right.

Quote:
almost certainly these are the result of a designed 210F engine operating temperature and the resultant extremely high engine compartment temperatures.
I think you will find your engine compartment temperature is related to how much fuel is being burned and not the opening temp of the thermostat. The BTUs you are generating are not any different because the thermostat opens at a lower temperature. The total heat generated is based on how much gas you are burning.

Quote:
Certainly Chrysler engineers know more about it than most anyone, but their ideas of initial efficiency and my ideas of ultimate efficiency probably don't align very well...
So why not simply run 4.2 qts of diesel through the crankcase? Initial versus ultimate efficiency is an interesting concept which I hope to read up on.

Rant over. My apologies again to readers and the OP. I will in the future do my best to never publicly disagree with Mr. Bunyard. I do however respectfully reserve the right to contribute as I can and may to these forums.
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Old 04-07-2020, 14:10   #93
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Re: Another Low Oil Pressure Query

Quote:
Originally Posted by Scubaseas View Post
My apologies to wingsail, the OP for drift. I promise this will be the last entry by me on this topic unless asked. I had hoped a cordial conversation could have been had in regards to the function of a seemingly duplicate valve, as in what exactly is the function of the second valve to regulate pressure or (now) volume. I will apologize again to Mr. Bunyard for offending him is some fashion and to the forum for my poor command of written English or my writing style.

Your repeated attribution of me taking offense and somewhat insincere-sounding apologies do not, to my ears anyway, ring true

I agree with jimbunyard for the most part excepting perhaps the following quotes which are not exhaustive.

Well if by 'not exhaustive' you mean there were more that --uhhh--offended you?--pissed you off? why hold back? List 'em, all so everyone can see how mean old Mr. Bunyard really is...

Quote:
I fear your use and understanding of written English is about on par with your mechanical knowledge. Not sure what my right has to do with anything, but if you mean my being right, that has nothing at all to do with it. The OP is asking questions about things he has less information about than others have. It's important to give the most accurate information possible to ensure the most complete understanding in the shortest amount of time. Inaccurate or incomplete information is at best confusing and a waste of time.
As noted and implied in the quote above, I take what I write and advise seriously, for, among others, the stated reasons. My opinion about your English usage and mechanical understanding seems to be at least somewhat borne out by several of your comments below.


And off we go! Sorry, maybe it's a cultural thing but I do not consider the above statement to be warm and fuzzy. Apparently Mr.Bunyard's umbrage is in response to me disagreeing with him. Which I apologized for and will do so again. I get he is right and everyone else is wrong but apparently me more than anything or anyone else.

Why on earth would you apologize to someone for disagreeing with them? That is an insult to both them and to yourself. If you disagree, tell them why. Depending on the topic, somethings can be disagreed upon; with both sides able to be 'right'. With others only one answer is correct.


Quote:
So there
Really?

Maybe it is a cultural thing, since 'So there' in this case was a reference to pre-to-early-teen behavior regarding things that were taken semi-seriously or seriously at the time but had no real import in the long run; i.e. it was relatively dry humor poked mostly at myself.

Quote:
Why? Believe Pascal's principle has to do with pressure in a closed system, which an engine's lubrication system is not.
Pascal applies up to the moment you crack open the pressure, volume, regulation or relief valve or whatever it's now called. But somehow you get an extra 21.4 PSI. I will concede it may simply be that I can not understand English and all of this nonsense is entirely my fault.

No it doesn't, because the system is never closed. All the bearing clearances and nozzle outlets prevent it from being so. I've no idea where you're getting 'an extra 21.4 psi'. Unless you're conflating my analogous use of 100 psi air compresser pressure (a rough standard for shop air tool use, around here anyway) with the pressure in the lubrication system under discussion.


Quote:
The miscomprehension seems to be in the function of the first valve and the relation of volume to pressure. Perhaps it'll help to think of it in a different system. Imagine a big-ass screw compressor (the oil pump) filling a 100 gallon air tank (the lube system) with a half inch hole in it (the fully open 43 psi 'regulator' valve). You can still run all the tools in the shop at 100 psi because the volume supplied by the compressor pressurizes the system faster than the hole in the tank can reduce the pressure.
I couldn't agree more. I do not see how you can run the tools at 125PSI however.

Quote:
Maybe the valves are rated on different scales, perhaps working vs static pressure.
I doubt this.

Of course they're not, nor is the book wrong. That was just a rhetorical iterary device to point to the answer being suggested as correct unless otherwise proved wrong.

Quote:
Since I've no official "bona fides" (are you one of the Coens in disguise?) other than designing, building and repairing all things mechanical for as long as I can remember (and according to people who should know [parents and siblings] since before I can remember [about 9 or 10]), perhaps you can decide which of the three seems more likely, or can provide the real answer.
The real answer is you can't explain it given what you have said up to this point in time. It was a rhetorical question.

Because you or anyone else can't understand the explanation only means that it hasn't been explained to you. I would be more inclined to believe that your request for my 'bona fides' was rhetorical if you hadn't included yours before asking for mine. But it's equally humorous to me either way.

Quote:
At this point the metaphor starts to fall apart; I think Bernoulli might start to come into play, but for our purposes it should explain the 'pressure conundrum' well enough.
It does not explain it and it's analogical reasoning you are using. Bernoulli does not come into play here. The expression you may be looking for is Volumetric Flow Rate.

As stated at the begining of post 91, I've given it my final go. The answer should be obvious to anyone who has used an air tool and had the compressor kick off while still running the tool, or had the well pump turn off while still taking a shower.

Why would I be looking for that expression?


I understand you may never be wrong but in this case you may not be so much right.

I'm wrong all the time, but usually catch it myself. since I try not to say or do anything until I'm at least relatively sure of what I'm doing or saying. If I'm wrong in this case, by all means give me some reasons. Saying "you're wrong' is not a reason.

Quote:
almost certainly these are the result of a designed 210F engine operating temperature and the resultant extremely high engine compartment temperatures.
I think you will find your engine compartment temperature is related to how much fuel is being burned and not the opening temp of the thermostat. The BTUs you are generating are not any different because the thermostat opens at a lower temperature. The total heat generated is based on how much gas you are burning.

I'nn not going to get into another fiasco here, but we're talking about heat disspation, not heat generation.

Quote:
Certainly Chrysler engineers know more about it than most anyone, but their ideas of initial efficiency and my ideas of ultimate efficiency probably don't align very well...
So why not simply run 4.2 qts of diesel through the crankcase? Initial versus ultimate efficiency is an interesting concept which I hope to read up on.

Because I'm not having problems with sticky regulator valves or hydraulic lifters. If I did I would, and when I rebuild the motor in 30 or so thousand miles, as a 'preclean', I probably will. Doubt you'll find much or anything about initial versus ultimate efficiency at least under that phrase, since I just coined it, but in this context Chrysler's 'initial' efficiency is based on fleet fuel economy and reliablity through the vehicles warranty period, while my 'ultimate' efficiency is based on the longest overall vehicle and component life with the best fuel economy.

Rant over. My apologies again to readers and the OP. I will in the future do my best to never publicly disagree with Mr. Bunyard. I do however respectfully reserve the right to contribute as I can and may to these forums.
And I thought you actually were concerned about how the system we were (I was?) discussing operated.

At least now we know who was actually "pissed-off" or "offended".

And with that, I'll consider the operation of the lubrication system of the Yanmar 3JH2 'explained'.

Whew...
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Old 08-08-2020, 11:19   #94
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Re: Another Low Oil Pressure Query

FOLLW-UP
It's taken us a while to finish this project, a few side trips intervened, but we're now finished.

We installed a mechanical gauge and that worked well to indicate good solid oil pressure at all RPMs, (50lbs, 3.65 bar), a big relief.

We sent for new sending units for the oil pressure gauge and the oil pressure alarm switch as well as some adaptors and a Tee. And found, when they arrived, that the BSP threads on the Tee and adaptors won't actually screw into the BSP threads on the engine. (wow)

Against some advice, we used a BSP die to re-thread the the brass Tee which worked.

Yesterday we installed the new sending units and tested the gauges by running the engine at 2400 rpm for 45minutes.

Result: 54lbs (3.75 Bar) on both gauges at all rpms and cold and hot engine and the alarm works as it should.

Now I just have to worry that the Tee does not break or the mechanical gauge, which is mounted on the engine, doesn't fail due to vibration but I'm marking this one done.
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Old 08-08-2020, 16:38   #95
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Re: Another Low Oil Pressure Query

Now I just have to worry that the Tee does not break or the mechanical gauge, which is mounted on the engine, doesn't fail due to vibration but I'm marking this one done.[/QUOTE]

Good that your problem turned out to be not a problem
You can mount the tee & gauge off engine as scubaseas & I suggested in earlier
posts . A hydraulics place would make you up a bit of flexible hose or they might have something in an auto store.
I have the tee on the engine on on our Yammer single but a flexible hose to the gauge. Tee has been flinging back & forth wildly due to vibration for 6 years now with no failure but it's ss 316 material. Think our Yammer would shake the needle off oil pressure gauge if we mounted it on engine. However I'm sure your multi-cylinder would be less violent.
Thanks for follow up & warning on aliexpress adapters, I won't suggest them again I just saw them but hadn't tried them sorry.
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Old 08-08-2020, 17:44   #96
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Re: Another Low Oil Pressure Query

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Originally Posted by wingssail View Post
[
Now I just have to worry that the Tee does not break or the mechanical gauge, which is mounted on the engine, doesn't fail due to vibration but I'm marking this one done.
Most of the time there is an extra port or two into the oil galley that’s plugged off. Very often this is done to support different installations, maybe some tractor has a frame rail that runs where your boats oil switch is located etc. so there are extra unused ones.
They are often located near the oil filter. Find a plug, unscrew it and if oil drips out, then of course it’s an oil galley, unlikely, but if antifreeze drips out, just stick the plug back in and keep looking.

On my old 4JHE there were extra plugs that were obvious for both the oil pressure and the coolant temp gauge.

Thanks for the update, most don’t and you never know what solved the problem, and that’s important info, completes the thread.

If you go the hose route, it may be tough to find a BSP thread hose, I just retapped my block to NPT, it’s not really tapping, the threads are so close that it’s more of a thread straightening thing, no drilling required.
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Old 08-08-2020, 18:16   #97
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Re: Another Low Oil Pressure Query

[QUOTE=wingssail

Now I just have to worry that the Tee does not break or the mechanical gauge, which is mounted on the engine, doesn't fail due to vibration but I'm marking this one done.[/QUOTE]

The standard practice in an airplane engine instillation is to put a small jet in the engine fitting, something like .030". If anything fails, you have a small leak. Also, fill the line from the engine to the indicator with a light oil, it won't clog.
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