Oil system myths

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Correct. But does the wing create the pressure differential? Or does the resulting change in air speed (flow) across the two differently shaped surfaces create the pressure differential? That’s the rediculous argument that is being had.

That is stupid. It's the wing. If it was not shaped like it is so that air didn't speed up as it flows across the top, there would be no low pressure area. A straight wing would not make this happen. At any rate, that argument is almost splittin hairs.
 
25k+ elevation is a whole nother thing.
Very few people get that high.

I guess that depends on perspective. A lot of us are already there considering the Mariana Trench at Challenger Deep is over 36,000 feet. Perspective is everything.
 
Most people think they have trouble breathing at high altitudes because there is less oxygen in the air . NOT

They have trouble breathing at high altitude because there's less atmospheric pressure and it's harder to make a low pressure area since the atmospheric pressure and the pressure in your lungs is closer together.
 
That is stupid. It's the wing. If it was not shaped like it is so that air didn't speed up as it flows across the top, there would be no low pressure area. A straight wing would not make this happen. At any rate, that argument is almost splittin hairs.
Exactly my point.
 
I agree with all of this and what Justin said in post 91. Im not disagreeing at all.

I know that when I sit down and figure out what I need for an oiling system, I figure pressure into it as well. At one point I was carrying 100 plus PSI and it made more power. That was with the same pump. I had an external bypass that was adjustable and on the dyno I kept increasing the pressure until the power went down.

And on that system I had blocked the bypass in the pump and used a line off the bypass to put the oil back in the pan in front of a baffle so it didn’t blow return oil back across the pickup and uncover it.

So yes, pressure goes hand in hand with flow, until the pump is producing enough flow to the point where the flow and pressure stays the same because the the system can’t use anymore oil and the bypass opens.

I hope that made sense. In my head it does, but when I read it back I’m it so sure.

The best example of this is using full groove mains and a standard volume pump. You will have lower oil pressure at idle because the rods are getting oil all the time. And that adds to the leaks at the rods.

So the standard volume pump doesn’t produce enough oil at idle and slower engine speeds to produce the same oil pressure because of the added flow loss to the rods.

At some point the standard volume pump will produce enough oil flow to open the bypass and that is the pressure maximum. Any more RPM (flow) increases don’t change the pressure because the bypass is open.

Take that same engine, with the same bypass relief pressure and add a high volume pump. The oil pressure will increase at idle and lower RPM because the pump is producing more oil at the same RPM because the rotors are taller, which equals more displacement.

At some point (earlier in RPM because the pump produces more flow at any given RPM with the HV pump verses the standard volume pump) the pump will produce enough oil that the system restricts flow to the point the pressure rises, until the relief opens and the pressure should stay the same regardless of RPM increase, again unless the bypass can’t flow enough and the pressure increases.

I guess IOW’s, the HV pump has more flow at a lower RPM than a standard pump so even with all the same parts and leaks the HV pump has more volume, thus more resistant and more pressure on the gauge until the bypass opens.

This is why I always say to use a HV pump on ANY Chrysler engine using full groove mains, or a solid roller cam with Chrysler oiling and a groove around the cam bearing(s) that feed the heads, because that extra system leakage requires more oil. And if you don’t give it the system suffers. And that’s usually at the end of the feed line. Which is the rockers.

You can have 20 pounds on the gauge and zero at the rockers (tested that). So I don’t like to see anything less than 40 at idle to keep oil flow to the rockers adequate. Unless it is bone stock or close to it.

As to adding oil and keeping the pressure up...that includes many other things.

One is application. On an OE engine, an extra quart of oil in each engine is burning money to the bean counters, so they are built with the lowest oil pan volume the engineers can slide by the nerds. Once you start to make changes to the engine AND/OR chassis, that pan becomes an issue. Increase the RPM and the engine WILL hold more oil.

So the issue isn’t the engine holding more oil, it’s the pan is wrong for the application. A stock pan is pretty much useless on anything but a stock engine. Start modifying the engine, use a bigger pan.

Since oil retention does go up with RPM, pan design, volume and windage trays and crank scrapers become much more important.

There are people running 4 or 5 quart systems on stuff shifting at 8k or more. But the pan is designed to do that, and they have trays and scrapers and baffling that would boggle the mind. And vacuum pumps. All that stuff matters.

Another factor that needs to be looked at is pickup to pan placement.

I can’t tell you how many Chrysler guys using a stock pans listen to the Chevy morons and put the stock pickup .250-.375 off the pan! That pan and pickup was designed to have an SLIGHT interference fit to the pan.

If you need a 1/2 inch impact to pull the pan down to the block you have too much interference. If you move the pickup away from the pan, it can’t pull the oil out of the pan and it will leave a quart or more in the pan. So you add a quart or two to make up for bad engine building.

Again, that is not a pump issue. That’s a pan issue.

Any engine running full groove mains and a stock pan is asking for trouble. The increased oil flow demand makes that stock pan questionable at best.

So I get what you’re saying about times when adding a quart of oil fixes an issue. I’m saying that’s not a pump problem, but a pan problem.

No serious engine should be built without adding capacity to the pan.

A stock pan is 4 quarts. A 6 quart pan is a 50% increase in pan volume. That’s huge. An 8 quart pan is a 100% increase in pan volume.

Increasing RPM or oil volume through the engine or both means you need more pan volume. If you don’t give the pan more volume, the first thing that suffers is the rockers. Run the RPM and the bearings will show you how pissed off they are.

Thank you, YR. So it seems like the sump/pan is the culprit for most oiling issues.
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Here's another way to look at the oil system and the pan being "sucked dry".
If there is no oil available at the pickup tube there will be no oil flow. It doesn't matter how much oil the pump has the capacity to flow or how much resistance to flow the engine provides there must be oil available to the pump.
Can the pan be sucked dry? I'm not sure thats the right question. Can the pick up tube become uncovered? Yes.
I think what's being discussed are oil flow problems and there not happening idling in park. Oil demand changes in an engine when rpm changes and oil supply is affected by how we use the vehicle. From drag racing to rock climbing to circle track to road racing etc. We have to keep the pickup tube covered up with oil. Just look at the extreme measures that are taken in pan design , baffles, trap doors, oil capacity and etc. to accomplish this. So to answer the question "Can a pan be sucked dry?" I don't know. Can a pickup tube get uncovered? Yes, happens all the time. Is that cavitation? I don't know.

^^^^^This is where I was going with my question. Perhaps cavitation was the wrong term, it's aeration that I was thinking of. Either way, lack of oil at the input of the pump is where the problems begin.

25k+ elevation is a whole nother thing.
Very few people get that high.

Oh I can think of a couple lololol

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Thank you, YR. So it seems like the sump/pan is the culprit for most oiling issues.
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Cheech and Chong Classic movies


^^^^^This is where I was going with my question. Perhaps cavitation was the wrong term, it's aeration that I was thinking of. Either way, lack of oil at the input of the pump is where the problems begin.



Oh I can think of a couple lololol

View attachment 1715629729
 
Thank you, YR. So it seems like the sump/pan is the culprit for most oiling issues.
View attachment 1715629727



^^^^^This is where I was going with my question. Perhaps cavitation was the wrong term, it's aeration that I was thinking of. Either way, lack of oil at the input of the pump is where the problems begin.



Oh I can think of a couple lololol

View attachment 1715629729


Yes, the pan/pickup is the biggest oiling system bugaboo until you start getting to 8K RPM, then other issues are just as critical.
 
riddle me this??? why a cigarette burn up setting on a ashtray at say 800 ft above sea level, but will barely burn at say 14,000 ft above sea level?? itll run like a poorly rolled joint at best!!
 
Speaking of oil pumps sucking the pan dry (or ambient crankcase pressure forcing all the oil into the pickup, if you prefer), this is transparent oil pan and valve cover experiment is interesting to see:
 
I lost a couple of factory 340s when the oil-level was a quart low.
So
on my 367, I installed a 7 qt road-race pan, and a HV pump, and did all the oiling mods except the crossover. The first time I took the Valve covers off, and saw all the oil up there that the Eddies were retaining; I had thoughts. And when I removed the Airgap, and saw all the oil puddling between the lifters, I had more thoughts.
So, that winter, having swapped the engine out for a 318 winter engine, I set to cutting channels and drilling drain holes.
The following winter, swapping engines out again, I saw the the channels could be deeper and the holes bigger.
The third winter, I saw that the topend was now fairly dry and the pockets empty. So I now run 5 or 6 quarts in the pan, getting the oil a bit further from the crank, being confident that the oil is getting back to the pan as fast as the design allows.
And I haven't seen any damage inside the engine at all, traceable to lack of oil.

Just so you know, I one-time entered the car in a grass rally cross event. It was a second gear only track for me, spinning the street tires the whole 64 seconds. All I did was steer, with the engine more or less on the rev-limiter.
As I crossed the finish line, I noticed a huge oil-cloud following me. Which I traced to the PCV system. Apparently, the baffles and filters in the Covers couldn't deal with high rpm for 64 seconds atta time.
Also, the oil-filter had blown off the plate, and puked oil onto the header. That, I fixed by installing a second plate, and drilling more and bigger holes, and switching to a retaining bolt with a round hole and drilling that out bigger as well. It never did it again.

So, I know a lot has been said about the Mopar oil system not being able to suck the pan dry, and I cannot argue that yes it can...... but I do know that the stock Eddies don't drain fast enough to run 6 or 7 quarts in the pan and spin 5000 to 7000 for 64 seconds.
No, I didn't win,lol, I was 5 seconds off the fastest time, of a prepared car.
I know it sounds cheezy, but I was just there, with my 16 year old son, to have fun, and give the locals something to talk about. I had the biggest barge there and, I think probably the only V8.
And we did have a lotta fun. Nothing broke and we left thru the same gate we drove in thru. Well not quite true; I cracked the pan when landing a jump on the home straight, which was there to slow the cars down. I saw it too late and the crowd loved it. After trying unsuccessfully twice to braze the crackss shut, I dropped the pan and had it professionally welded; no more problems.
And then I fabricated a skid-plate.....
 
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Its worth mentioning the oil you see when you remove a valve cover is 'static' oil. That means it's there all the time*. It puddles up once you first start the engine then it stays there, at least in volume. So it really doesn't reflect how well the oil drains back. The trick would be to install a clear valve cover and watch how much oil puddles up in addition to the static amount.

Then, the more oil that drains back through the lifter valley, the more oil that can get beaten into a froth by the rotating assembly. If an old boy were strictly interested in the best 1/4 mile pass, he'd limit the drainback to minimize windage, then keep on hand lots of extra rod and main bearings in case he ran out of oil. The point being...drainback is good but too much in the wrong places can be bad.

Someone should invent a system that uses a crank-driven pump to evacuate the engine of 'used' oil, then send it to a tank where it could be held until the oil pump is ready to suck it back out and redistribute it into the engine. The sump of the engine would contain only the bare minimum of oil. While it wouldn't be completely dry, we could refer to it as a 'dry sump' type of system to keep matters simple. If I weren't spending all of my time modeling Hunter Biden underpants for Japanese tourists, I'd sit down and invent such a system.

*Unless you drive on a 45 degree embankment or perhaps some other embankment of a different, yet still effective, degree.
 
Its worth mentioning the oil you see when you remove a valve cover is 'static' oil. That means it's there all the time*. It puddles up once you first start the engine then it stays there, at least in volume. So it really doesn't reflect how well the oil drains back. The trick would be to install a clear valve cover and watch how much oil puddles up in addition to the static amount.

Then, the more oil that drains back through the lifter valley, the more oil that can get beaten into a froth by the rotating assembly. If an old boy were strictly interested in the best 1/4 mile pass, he'd limit the drainback to minimize windage, then keep on hand lots of extra rod and main bearings in case he ran out of oil. The point being...drainback is good but too much in the wrong places can be bad.

Someone should invent a system that uses a crank-driven pump to evacuate the engine of 'used' oil, then send it to a tank where it could be held until the oil pump is ready to suck it back out and redistribute it into the engine. The sump of the engine would contain only the bare minimum of oil. While it wouldn't be completely dry, we could refer to it as a 'dry sump' type of system to keep matters simple. If I weren't spending all of my time modeling Hunter Biden underpants for Japanese tourists, I'd sit down and invent such a system.

*Unless you drive on a 45 degree embankment or perhaps some other embankment of a different, yet still effective, degree.

.....or just run a dry sump.
 
Well, I get that; there are books written to that effect. But;
firstly, I am a streeter, and secondly,
IMO
if all the oil in the pan got to be stagnant in the head ......... you can imagine how long my rods would survive.

I cut the drain channels in the soft aluminum, at the back, so that the oil could get away faster, wouldn't spill into the valley, and so that contaminants would be washed into the pan, to be trapped from thence, in the filter. And my hope was to redirect the oil falling thru the pockets to find it's way onto the flat-tappet lobes.
Since the engine now has well over 100,000 miles on it,some of them at over 7000 rpm,
IDK,
I think it's working.

As a streeter, I pump a lot of cooling oil up to my valve gear, so it will last for 100,000 plus thousands of miles, I don't care if it costs me power, because I already have enough to go 93mph in the Eighth; yes with the holes and channels.
I mean, that's why I installed the HV pump, not to dump it out the relief and straight back into the pan. No, I installed the HV pump so I could redirect some of it as a coolant to the springs, (which regularly see 7000 to 7200 with 549/571 lift and a 4-speed), and some to protect my expensive aluminum rockers with their roller tips, and some to be blasted onto cylinder walls, thru the piss-holes in the rods.
My engine was screwed together to go the distance, and don't care about some extra windage, or some slight powerloss, which is also why I chose a 360 over something smaller.
My engine also sees a lot of rpm below 1000, cuz it's a manual trans. Sometimes, lots of times, the tach will be saying 550 rpm at 4 mph, because, well, I want to drive 4 mph. So here is another situation where that HV pump is earning it's keep, pumping oil over the valve springs; and my channels allow that hot coulda-been-stagnant oil, sitting on the 207+ degree aluminum heads, to be carried back into the pan ASAP where it can get rid say 30% of that heat.

If my thinking is right, then that long engine life,
is worth far more to me than
the 93mph in the Eighth, which number I only know because I let myself be pressured into going to the track one time. I'm gonna say, that I would give up a bunch of horsepower, to go that 100,000miles.
The Wallace says 93@3456 pounds is 433 hp, with the current set-up.
I have driven that car with more power and with less power, and am confident to say that I would give up between 20 and 50 horsepower, to keep the 100,000 miles. But thankfully, I didn't have to lol.

As you so politely said
"it's worth mentioning"
I find no fault in your assessment.
And in your thinking, perhaps more race-car oriented, I totally understand it.
But my engine spends maybe 98% or more of her life at 5600 rpm or less. Perhaps 60%, at less than 4000rpm.
Cuz, you know, it's a streeter and the speed limit here is 65 mph which being, less than 5600 in second gear,lol, and ~2260 in overdrive.
 
Believe me, I have a lot more respect for a street engine that lasts than a moment-of-glory race engine.
 
That reminds me of a guy I used to know that drag raced air cooled VW's. He had 12 engines built exactly the same and changed them after every run! That covered all his time trials and eliminations. He then freshen them up during the week for the next weekend's drags. He claimed he had less breakdowns, and cheaper repairs that way as his engines were pretty radical and sometimes would blow after 2-3 runs without a teardown.
 
The pump sucking the sump dry, plug up some of the drain back holes with sludge and that pump will suck it dry. Hemi valve train comes to mind.
 
I do wish we could still buy the cast covers with the pickup hole in them. I have been on the lookout for one. They don't seem to pop up for sale very often.

If you post the link, I will put on a pot of coffee and take a good listen.
Made mine on the 340 used a pipe from a 3.0 V6 (much bigger) straight down into a rear sump Magnum pan (machined the rear main cap for the pan)
 
Made mine on the 340 used a pipe from a 3.0 V6 (much bigger) straight down into a rear sump Magnum pan (machined the rear main cap for the pan)

Do you have any pictures? If you're like me you probably don't, but it never hurts to ask.
 
Do you have any pictures? If you're like me you probably don't, but it never hurts to ask.
Yes I do, already had one long time stocker guy loving my ‘adaption’.
people need to read what Smokey has to say about pumps and pans for circle
and drag racing. This was about 40-50 years ago
 
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