Author Topic: What the heck is going on in the oil pan?  (Read 10672 times)

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jayb

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What the heck is going on in the oil pan?
« on: August 05, 2021, 04:22:59 PM »
I've been doing a little more testing on the dyno mule with my cylinder heads on it this week (up to 894 HP now).  After the last go around a few weeks ago I had some conversations with a couple of my head customers, and John S (oldiron.fe on the forum) mentioned putting a window in the oil pan to see what was happening.  Ever since I started with this engine on the dyno last September, I've noticed that at the higher RPM pulls I have a significant decrease in oil pressure, typically starting around 65 psi at 5000 RPM and dropping to about 50 psi at 7000 RPM, with the oil temperature around 180 degrees, using 10W-30 VR1 Valvoline oil.  Higher oil temps of around 200 degrees make it a few psi lower, and I really wasn't too comfortable with those levels.  I've seen this oil pressure issue before with vacuum pumps, so I figured that was a contributing factor, but I thought it would be interesting to see exactly what the oil in the pan was doing.

Since I was planning on pulling the pan to check the bearings, I decided to go ahead with the window, potentially wrecking the oil pan but hopefully learning a few things in the process.  After checking all the bearings (which looked almost new), I cut a big rectangular window out of the Milodon 7 quart oil pan and bolted a piece of 3/8" thick clear polycarbonate to the side, using a bunch of The Right Stuff to seal it.  The engine is using a Moroso windage tray between the block and the pan, and a Precision Oil Pumps high volume pump using the small spacer between the spring and the cup plug.  I've also installed a new vacuum pump from Star Machine to replace the GZ Motorsports pump that I had been running previously.  This pump gave me a few more inches of vacuum, and probably contributed to the latest HP numbers.

I set up a camera to take videos of the window in the oil pan while the engine was running, and during a dyno pull.  I also rigged up a tach so that you could see the engine speed in the video, but unfortunately the tach I used didn't work, or else it didn't like the tach signal from the MS3-Pro.  Regardless, I started testing the engine and then watching the videos.  I was really surprised at what I saw.  The first video link is below; this is with a total of 8 quarts of oil in the engine.  It takes a while in the video to get to the actual dyno pull, which happens starting around 1 minute and 45 seconds in.  The oil levels are marked on the pan in the video:

https://youtu.be/ZPL_05cKRKY


Wow, the amount of air entrained in the oil during the actual dyno pull is shocking!  Lots of big bubbles circulating in the oil, certainly contributing to aeration of the oil coming out of the pump.  As my dyno junkie friend Royce said, it looks like you are spraying a garden hose into a bucket of water.  There appears to be about 6 quarts of oil in the pan during idle, and it drops to about 4 quarts during the pull.  A while back on the Engine Masters show on Motor Trend on Demand, they did an experiment where they saw oil pressure drop as engine speed increased, attributed it to foaming of the oil, and solved the problem by taking some oil out of the pan.  I thought I would try the same thing, so we pulled 2 quarts out of the pan, and ran the test again.  Here is the video:

https://youtu.be/cQRGg-nI8m0


Well, that didn't work, we still had the same drop in oil pressure as before up at 7000 RPM, we seemed to have the same amount, or even a bit more, of foaming and bubbles in the oil, and we didn't make any extra power.  The oil level in the pan looked like 4-1/2 quarts during idle, and about 3 quarts at peak RPM. 

The obvious next test was to remove the vacuum pump and see how it looked without the pump on the engine.  We went back to 8 quarts of oil in the engine, and ran without the vacuum pump.  Here is the video:

https://youtu.be/sd29Ye2E0Q4


Unfortunately for this video I had decided to remove the tach (which wasn't working), and apparently after repositioning, the camera position was off a little compared to the last two videos, and we got some glare from the window that kind of obscured the oil.  However, if you look closely you can see that the oil level in the pan drops quite a bit farther in this video than in the first one, and there still seems to be a whole bunch of foaming and air bubbles in the oil.  BUT, the oil pressure stayed stable throughout the dyno pull.  Unfortunately the oil pressure win was offset by a large HP loss.

Based on the fact that the engine has been behaving like this (oil pressure wise) for several dyno sessions, and that the bearings looked very good when I inspected them, I'm not overly concerned about the oil pressure issue when the vacuum pump is running.  However, it seems like there ought to be some oiling system modifications that could mitigate this problem.  One thing I tried with this new vacuum pump setup was a second vacuum port lower in the engine; this was recommended by Star Machine, and also Andy Miller at Olds Performance.  I actually put a hole through the side of the block right across from the #3 main cap, and then milled a slot in the main cap to allow air from the crankcase into the slot, through the hole, and out to the vacuum pump.  The hope was that since the hole in the block was shielded by the cap, it wouldn't draw in too much oil, but that didn't work, so I went back to a single line from the valve cover to the vacuum pump.  I might try that again next time around with a baffle over the slot in the cap; Lykins also suggested going through the fuel pump opening in the timing cover, so I could try that too.

Another thing is the windage tray.  The Moroso tray has louvers that strip oil off the crank, and several of those louvers point straight down at the oil level in the pan.  You can see this in the videos when the engine is idling, one of those louvers is right above the window and oil is coming straight down.  It seems like using the Ford windage tray, which has louvers only on the right side of the engine and shoots the oil horizontally through the louvers, rather than vertically, would be a better design.  Also it seems like a kickout on the right side of the oil pan, designed to catch that oil and give it a chance to slow down before it hits the rest of the oil in the pan, would be good.  It's also possible that a screen on the windage tray, like the Canton pan has, would lead to less foaming in the oil.  Maybe no windage tray at all would work best? 

Maybe the standard volume pump would yield an improvement.  And of course if you ran a really, really deep pan, that also might help.  The list goes on...

I'm sure there will be a million theories on the best approach to this issue, but the problem is there is very little data to back up the theories, and getting data requires changing up oil pans, windage trays, oil pumps, etc., which of course is a huge pain.    But if I go forward with any modifications I will certainly post them here for general interest.  I'm not sure if there is really HP to be had with a better oil pan setup, but an improvement in the stability of the oil pressure would be a worthwhile goal.
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

Hemi Joel

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Re: What the heck is going on in the oil pan?
« Reply #1 on: August 05, 2021, 09:49:34 PM »
Professor of FEology, have you tried a crank scraper?
What effect would that have?  How would a 2 layer windage tray work, with offset louvers?  It seems a very deep pan would be beneficial. 

cammerfe

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Re: What the heck is going on in the oil pan?
« Reply #2 on: August 05, 2021, 10:26:46 PM »
During a walkthrough with Jack Roush, of his Prototype Engine Facility, some years ago, he pointed to a set-off area and, speaking of the activity there, he said, "There's a lot of power to be found in a properly constructed oil pan."

It is my present intent to use a dry sump system on every hot rod engine I make use of from now on. I'm sure you're familiar with Dailey Engineering in Temecula, CA

KS

Stangman

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Re: What the heck is going on in the oil pan?
« Reply #3 on: August 05, 2021, 11:06:20 PM »
I don’t know if I’m the only one thinking that that pan with the engine off needs at least 1 qt if not a quart and a half. It just seems low for a deep pan. Are there certain oils that have a better anti foaming agent in them.It seems like with the vacuum pump the last couple of inches in the pan aren’t as foamy if you were to put an extra qt maybe the bottom will be less foamy. Just thinking out loud.

cjshaker

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Re: What the heck is going on in the oil pan?
« Reply #4 on: August 06, 2021, 07:10:20 AM »
I think it's the crank beating the oil droplets into smaller, aerated droplets, as it returns. A knife edged crank and well done scraper would probably help in that area. It would be interesting to see what the screen tray does during a pull, but as long as the bearings come out looking good, I think it's pretty much a non-issue. A dry sump is obviously the best choice for an oiling system, but is it really worth the expense and logistics issues that go with it? On the vast majority of builds in 1/4 mile cars, I think it isn't, especially given the added weight. In a road race application or land speed run, or any very high HP build, then it's a different story. But having said that, learning is always a good thing, so any further testing done is always a plus (not saying you should take on that endeavor).
Doug Smith


'69 R-code Mach 1, 427 MR, 2x4, Jerico, 4.30 Locker
'70 F-350 390
'55 Ford Customline 2dr
'37 Ford Coupe

My427stang

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Re: What the heck is going on in the oil pan?
« Reply #5 on: August 06, 2021, 07:38:09 AM »
Different oil formulations can do very different things.  On early Powerstrokes at up to 4 digit pressures in the high pressure oil pump used for injectors, foaming can be very bad with the wrong oil, or as good oil gets older.

I think I'd probably try a completely different oil first, could be a 50 dollar waste, but better than hundreds.  They make anti-foaming additives too, but hit or miss when you add one to an existing package

Barring an oil problem, I would likely look at restricting where I could and maybe trying a standard pump for a bit less bypass, but I'd also look close at your pump to see if there is any wear or damage or if vibration beat up the pickup



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Ross
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- 70 Fastback Mustang, 489 cid FE, Victor, SEFI, Erson SFT cam, TKO-600 5 speed, 4.11 9 inch.
- 71 F100 shortbed 4x4, 461 cid FE, headers, Victor Pro-flo EFI, Comp Custom HFT cam, 3.50 9 inch

John67427

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Re: What the heck is going on in the oil pan?
« Reply #6 on: August 06, 2021, 07:39:30 AM »
Not that I can add any solution to what is happening and why, one thing I’ve learned over the years is when dealing with fluid or air you have no clue what’s going on unless you can physically see it and usually it’s a jaw dropping experience

jayb

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Re: What the heck is going on in the oil pan?
« Reply #7 on: August 06, 2021, 09:03:49 AM »
Not that I can add any solution to what is happening and why, one thing I’ve learned over the years is when dealing with fluid or air you have no clue what’s going on unless you can physically see it and usually it’s a jaw dropping experience

It certainly was for me LOL!
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

jayb

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Re: What the heck is going on in the oil pan?
« Reply #8 on: August 06, 2021, 09:05:07 AM »
Different oil formulations can do very different things.  On early Powerstrokes at up to 4 digit pressures in the high pressure oil pump used for injectors, foaming can be very bad with the wrong oil, or as good oil gets older.

I think I'd probably try a completely different oil first, could be a 50 dollar waste, but better than hundreds.  They make anti-foaming additives too, but hit or miss when you add one to an existing package

Barring an oil problem, I would likely look at restricting where I could and maybe trying a standard pump for a bit less bypass, but I'd also look close at your pump to see if there is any wear or damage or if vibration beat up the pickup

I was thinking about that Ross, I do have a case of 10W-40 Amsoil here, just wondering if that would make a difference.  It would be easy to try, maybe I'll give it a shot...
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

jayb

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Re: What the heck is going on in the oil pan?
« Reply #9 on: August 06, 2021, 09:14:17 AM »
Professor of FEology, have you tried a crank scraper?
What effect would that have?  How would a 2 layer windage tray work, with offset louvers?  It seems a very deep pan would be beneficial.

The Moroso windage tray has a kind of a crank scraper built in, but a better one might help.  I was actually thinking about a solid baffle welded to the bottom of the windage tray, so that any oil that came off the windage tray louvers dropped onto the baffle and was directed to the right side of the engine, before it returned to the pan.  This would at least prevent the straight down shot of oil that seems to be whipping up those big bubbles (again the garden hose into the water bucket comes to mind).

A dry sump tank is designed to run the returning oil around a circular path on the outside circumference of the tank several times, before it gets to the bottom of the tank; this is to remove air entrained in the oil.  It seems like if I could keep the oil up and out of the sump for some distance, yet continue to have it removed from the crank, it would mimic the effect of a dry sump tank. That would be a major modification to the oiling system, but maybe worth it...
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

cjshaker

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Re: What the heck is going on in the oil pan?
« Reply #10 on: August 06, 2021, 09:42:00 AM »
I was actually thinking about a solid baffle welded to the bottom of the windage tray, so that any oil that came off the windage tray louvers dropped onto the baffle and was directed to the right side of the engine, before it returned to the pan.  This would at least prevent the straight down shot of oil that seems to be whipping up those big bubbles (again the garden hose into the water bucket comes to mind).

A dry sump tank is designed to run the returning oil around a circular path on the outside circumference of the tank several times, before it gets to the bottom of the tank; this is to remove air entrained in the oil.  It seems like if I could keep the oil up and out of the sump for some distance, yet continue to have it removed from the crank, it would mimic the effect of a dry sump tank. That would be a major modification to the oiling system, but maybe worth it...

Since gravity is the only factor in oil returning, I don't think the "straight down shot" is forming the bubbles. Gravity doesn't increase with RPM, and there is no pressure added at RPM in that down force, as the hose analogy implies. There is more volume, but a small hose feeding water into a bucket at low pressure is no different than a big hose feeding water under the same pressure. Unless the "hose" is raised to a point where speed of return increases (picture a hose feeding at 1" height, compared to 3'), thereby adding pressure when it hits the water column, there still won't be bubbles. Only when pressure is added at the hose will it force air down into the water column. The crank on the other hand, has a huge influence with RPM. It's a massive aerator in essence.

Directing oil away from the crank is a known power builder, but also has other known benefits, like less aeration. That's where cam tunnels, scrapers and other trick oil mods come into play. But it still can't be eliminated entirely. Rod journals will still sling oil at the pistons, and those pistons will still shoot it directly back to the crank on the downstroke.
Doug Smith


'69 R-code Mach 1, 427 MR, 2x4, Jerico, 4.30 Locker
'70 F-350 390
'55 Ford Customline 2dr
'37 Ford Coupe

475fetoploader

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Re: What the heck is going on in the oil pan?
« Reply #11 on: August 06, 2021, 10:28:45 AM »
We used to buy an oil additive from International for the early ford Power strokes. It was created to help with foaming of the oil.  It came close to eliminating the effect created by 800 psi of oil pressure in the injectors.
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runthatjunk

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Re: What the heck is going on in the oil pan?
« Reply #12 on: August 06, 2021, 10:39:28 AM »
Well that's just fascinating.  It's a closed system (with leakage obviously) so it makes no sense to me how the vacumm can cause that kind a pressure difference.  The aeration just at idle was eye-opening, looks like one of Conleys pumps is needed here!  I'd be curious about a diesel oil for the anti-foaming but the shear volume of oil being thrown around I doubt there would be any signficant difference between oils of the same viscosity.
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jayb

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Re: What the heck is going on in the oil pan?
« Reply #13 on: August 06, 2021, 10:51:25 AM »

Since gravity is the only factor in oil returning, I don't think the "straight down shot" is forming the bubbles. Gravity doesn't increase with RPM, and there is no pressure added at RPM in that down force, as the hose analogy implies. There is more volume, but a small hose feeding water into a bucket at low pressure is no different than a big hose feeding water under the same pressure. Unless the "hose" is raised to a point where speed of return increases (picture a hose feeding at 1" height, compared to 3'), thereby adding pressure when it hits the water column, there still won't be bubbles. Only when pressure is added at the hose will it force air down into the water column. The crank on the other hand, has a huge influence with RPM. It's a massive aerator in essence.

Directing oil away from the crank is a known power builder, but also has other known benefits, like less aeration. That's where cam tunnels, scrapers and other trick oil mods come into play. But it still can't be eliminated entirely. Rod journals will still sling oil at the pistons, and those pistons will still shoot it directly back to the crank on the downstroke.

I don't agree Doug, gravity is not the only factor in oil returning.  The louvers on the pan that are directed straight down are allowing oil that is slung off the crank to be thrown at high speed into the rest of the oil in the pan.  As engine speed increases, the speed of the oil coming straight down is also increasing, and I think that is what is whipping up the oil so badly.  You might have to see the windage tray to understand what I'm saying...
Jay Brown
- 1969 Mach 1, Drag Week 2005 Winner NA/BB, 511" FE (10.60s @ 129); Drag Week 2007 Runner-Up PA/BB, 490" Supercharged FE (9.35 @ 151)
- 1964 Ford Galaxie, Drag Week 2009 Winner Modified NA (9.50s @ 143), 585" SOHC
- 1969 Shelby Clone, Drag Week 2015 Winner Modified NA (Average 8.98 @ 149), 585" SOHC

   

WConley

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Re: What the heck is going on in the oil pan?
« Reply #14 on: August 06, 2021, 11:17:09 AM »
From my experience, VERY few people truly understand what goes on in an oil pan.  In my early days at Ford, we were trying to get the 4.6L Modulars into production and there was a pesky issue of rods coming out of blocks. 

Finally they got smart and vacu-formed some clear oil pans.  It became clear that windage was keeping oil hung up and out of the sump.  It was also foaming badly.  All of the experts were shocked!  It took several weeks of adding guides and louvers to get the pan to an acceptable configuration.

Jay's videos show how hard it is to keep air out of the oil at any kind of rpm.  Yeah you could probably make the idle look better with a standard volume pump (or one of mine LOL), but at 7,000 rpm it won't change a thing.  What you need is enough of a sump to give the air time to get out before the pump pickup sucks it up.  Louvers and guides should be configured to hurry as much oil back to the sump as possible.

My big takeaway is this:  Did anybody else notice how quickly the oil clears up at shutoff with the vacuum pump on, or how it doesn't clear up with the vacuum pump off?  That's basic chemistry.  When there's low pressure, the air comes out of solution rapidly.  It's the same thing as opening a soda can.  The CO2 suddenly sees lower pressure, and out it goes.

The vacuum pump seems to really help the air separate from the oil in the sump.  That and a deep sump (giving more time before being picked up by the pump)  seem to be saving the day here.  I bet if you ran a clear line on the pressure side you could see the difference between vacuum pump and no vacuum pump.  At the very least you'd see what the bearings are getting...

Once again we are reminded how unlikely it is that these crazy contraptions even work!

Edit:  Jay - How much vacuum are you pulling in the pan?  Could it be that the oil level drops enough in the pan that the pump is seeing that reduced pressure on the pickup side?  At the beginning of the pull, you've got a big column of oil above the pickup.  At the end it's less than half that, likely with some air.  The pump is really putting out a delta pressure above what it sees on the pickup side.  When you're not pulling a vacuum, the pickup side is always atmospheric pressure.  Something to chew on...
« Last Edit: August 06, 2021, 11:31:15 AM by WConley »
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