What the heck is going on in the oil pan?

[Katz427]

I know a couple of responders (Ross being one), already mentioned oil. I can only recall an owner of a dirt oval track modified, that was having a concern, over what they considered excessive foaming of the oil. At the time they did say they were using Valvoline, VR1. Not sure if it was a full or blended synthetic. They finally switched brands to a full synthetic, which I believe ( but not sure ) to have been a Mobile 1 racing oil, and found significantly less foaming.

[blykins]

Fascinating tests, Jay! If your bearings aren't showing any signs of distress after being fed with aired up oil, then I'd thing your clearances and oil supply are sufficient. For what it's worth, I think my 504 has the same crank as this dyno mule and has been spun past 7k hundreds of times. The oil filters were showing metal when I pulled it down last year for inspection. The rod bearings had some ugliness. The crank looked great. When I built it, I used the old rule of .001 per inch of journal diameter to established clearance. So .0022-.0025 was the range of clearance on my rod journal bearings. About the same side clearances as this mule, .007-.010. I added .0005 clearance to the rod bearings when I put it back together. This dropped the oil pressure to 60psi (was 70psi) at 7k rpms (now I'm breaking the old rule of 10psi/1k rpm and almost zero psi at idle with a M57HV pump. But no metal in the filter. I wonder if aired up oil was my problem? Was running 15-40 Rotella. And I'm certain the oil was not getting up to it's designed operating temp. Have since switched to 10-30 Royal Purple.

My David Brown tractor has a oil bath style air cleaner. It has a series of screens stacked in the can body that the air is drawn through. I wonder if a stack of these type of screens at the top of the pans sump would help separate the air from the oil?

You may wanna look at something else here….

I routinely run .003-.0035 on rod bearing clearances on factory FE rod journal sizes  and have never seen anywhere near zero oil pressure, with a B pump or a HV pump. 

I also don’t notice that big of a change in oil pressure between running the FE and BBC journal diameters.  As a matter of fact, the only time I see a big pressure difference is a huge change in viscosity, such as going from 20W-50 to 5W-20.

I’ll also say that I have mistakenly ran .012” main bearing clearances before and even then saw 10-15 psi of idle oil pressure with a B pump.

I think you have an internal leak somewhere.

Also to note, I’ve ran anything from .012” to .030” rod side clearances and don’t notice any big changes there.  I pretty much let it end up where it ends up and not worry about it.  I don’t like anything under .012” though as things just look tight to me.

[cjshaker]

A couple of last thoughts on the aeration. First, you can notice aeration as soon as the engine is started. I wonder if it has anything to do with the cleaning agents in modern oils, unlike the older non-detergent oils? I wonder this because I don't believe I've ever seen any type of cleaning agent that didn't foam at least somewhat when agitated. That may be the reason for the need for anti-foaming agents that are also found in modern oils. It would be interesting to see what a non-detergent oil did for one pull.

As far as the pressure drop, it stabilized when the vacuum pump was disconnected. Doesn't that indicate a direct cause from the vacuum pump? Of course it's basic science that it's harder to pull on something when there is a vacuum operating on the other side. Jay, you even mention that you see this on engines with vacuum pumps. That would seem to indicate a normal operating practice. Even if the bypass closed as the pressure dropped, you are still pulling against a vacuum at its highest point. Do you see this pressure drop in your Shelby's engine, with the dry sump?

I do think Barry has a valid point about the pickup. The square or rectangular ones certainly can't be friendly to a steady flow path.

[blykins]

A somewhat relative topic over on YB:

https://www.yellowbullet.com/threads/oil-pans.2664650/

It may be worth it to try it without the windage tray.....

[Stangman]

I don’t know I’m still sticking to the idea of adding a quart which will give you an extra half inch or so at high RPM and trying another oil that may have a better anti foaming agent in it. When you look at the pan with it not running it just seems like your not even using the deep part of the pan. When the motor is at full song it looks like the oil at the bottom of the pan is starting to DEarate which is what makes me think an extra qt of oil. I also like Barry’s idea with the bell pickup it might stabilize the aeration under it before it goes into the tube.

[Barry_R]

When I was at Holley we were developing a gerotor fuel pump that ended up being marketed as the Volumax.  They had IIRC a 170 GPH iteration and a 250 GPH version.  The 250 had a bigger pump section and a stronger motor.  At first they both shared a common external body with a single 1/2" inlet and outlet.  The 170 performed perfectly well in the lab, but the 250 had a significant cavitation problem.  The outlet would develop a bunch of entrained air and made a lot of noise with a big drop in flow.  Eventually the guy doing the design and testing decided to add an additional 1/2 inch inlet opening (now we had two inlets and a single outlet.).  The air disappeared, the noise went away, and the outlet volume cruised right past the 250 GPH target with no distress.  The inlet side of a pump is pretty damn important...

[427John]

When I was at Holley we were developing a gerotor fuel pump that ended up being marketed as the Volumax.  They had IIRC a 170 GPH iteration and a 250 GPH version.  The 250 had a bigger pump section and a stronger motor.  At first they both shared a common external body with a single 1/2" inlet and outlet.  The 170 performed perfectly well in the lab, but the 250 had a significant cavitation problem.  The outlet would develop a bunch of entrained air and made a lot of noise with a big drop in flow.  Eventually the guy doing the design and testing decided to add an additional 1/2 inch inlet opening (now we had two inlets and a single outlet.).  The air disappeared, the noise went away, and the outlet volume cruised right past the 250 GPH target with no distress.  The inlet side of a pump is pretty damn important...

I agree 100% on the effects of inlet restriction,this was also discussed over on Bill's test rig thread it is incredible how air can find a path given enough pressure differential,kind of like a mouse crawling under a door.Running the larger diameter tube 427 type pickup may not solve these issues but it surely can't hurt.Ford chose to use the larger tube pickups on their performance engines such as the 427,Boss 302,429 Boss and CJ/SCJ's,in the case of the 429's they even developed a dual entry pump though I think that had more to do with rotor pulsing causing spark scatter but it may be related.As far as the funnel or bell shaped pickup while I've seen no comparison to prove it,it sure looks like should work better.

[Nightmist66]

Good testing, Jay. I've often thought about a clear pan or at least a window to see what's going on. One can only speculate until you can physically see something.

While I'm down waiting on parts for months(because I can't leave well enough alone), I'm working on my own Frankenstein oil pickup. I have the Milodon 31130 pan and the matching pickup(#18370), but feel there is room for improvement. Hoping to have an update shortly.

[CV355]

Very cool!

I wonder what the aeration would look like in a dry sump application just for comparison...

There's something alluring about dry-sump...  Would that extra $2k-$2.5k be worth it though? 

[turbohunter]

There's something alluring about dry-sump...  Would that extra $2k-$2.5k be worth it though?

Agree, but I keep going back to the quotes from the builders with wet sumps, “the bearings look great”.

[CV355]

There's something alluring about dry-sump...  Would that extra $2k-$2.5k be worth it though?

Agree, but I keep going back to the quotes from the builders with wet sumps, “the bearings look great”.

Oh absolutely.  I think the hundreds of millions of engines that work fine on wet sump principle would agree too.  But to Jay's point, how would we know what's really going on in there without looking?

[wowens]

How about a full clear bottom in the pan. May show a issue at pickup.

[jayb]

The dry sump is better, period.  Twice I've run at Drag Week with the big SOHC and the dry sump.  Both times after the multiple passes and a thousand miles of street driving during the event, I pulled the pan and nearly all of the graphite coating was still on the rod bearings.  Prior to the dry sump, the same combination would come apart and the bearings would look fine, but the graphite coating was mostly gone.  With the normal pan and pump the engine ran fine and had lots of oil pressure, and I doubt if the bearing clearances had increased in any measurable way, but the dry sump results after the same treatment was eye opening.  You don't get the oil pressure drop with the dry sump, and the oil isn't aerated, and it really shows.

Is it worth the extra expense and hassle?  I don't know, but it is definitely an improvement over the wet sump systems I've used...

[blykins]

Agreed, dry sump is it.  Bearings always look brand new on tear down.  Another pro is that a good dry sump pump will pull a lot of vacuum on the crankcase.  If the engine is sealed up tight, a good Petersen/Aviaid pump will pull 15 inches of vacuum without an issue. 

The only cons are the cost and the real estate it takes up.  If you buy nice hose and fittings with wide radius turns, etc., I bet you can spend $400-500 just on plumbing the thing up.

[turbohunter]

Oh absolutely.  I think the hundreds of millions of engines that work fine on wet sump principle would agree too.  But to Jay's point, how would we know what's really going on in there without looking?

With you all the way. Would love to own a dry sump but my little middle ‘merica existence can’t quite convince my wallet that it’s worth it.
That’s part of the reason I love Jays’ experimenting. Makes me think about how to do things better.

BTW
I think Barry is on to something also with the shape of the pickup.
Maybe a modified OEM style.