Dry Sump Plumbing

[Dave Haller]

I am putting out lots of feelers on dry sump plumbing because of the incidents I suffered with at Speedweek and don't want to ever happen again. Anyone have any site information I can go to and research proper plumbing and venting of a three stage dry sump pump system.
I have a breather line off of the top of the tank that runs to a breather tank mounted high on the firewall with a -12 line. Valve covers are sealed, engine is sealed. At fairly low rpm I filled the breather tank to overflowing and it blew out all over the engine, ect. Been told the tank was to full. It's a 4 gallon tank, had 3 gallons in it and running methanol. Understand methanol getting by the rings and adding to the voloume of oil. Been told to vacum the engine with a vacum pump or evac fittings in the headers. Been told to run two lines to the top of the tank then one line to a breather tank mounted behind the engine. No ring damage on leak down testing so that was not the problem.
Thanks for any suggestions or leads,
Dave Haller #93

[aswracing]

I bet if you vent the engine the problem will go away.

From my previous life racing sports cars, I had the best luck with a #12 line from the valve cover over to the top of the tank (a 4 gal Patterson), and then as you have it, from the top of the tank to a vented catch can.

I've heard of guys not venting the engine, and using a positive displacement pump that could actually pull a vacuum on the crankcase, together with low tension rings they supposedly get some more power out of it. But I never tried it.

[doug odom]

I vent both the tank and engine to the same catch can/breather. No problems. You can go to any dry sump web site or Moroso and see a drawing of the way you might want to do it.
Doug Odom in big ditch

[Rex Schimmer]

Dave,
Is your three stage pump, two scavengers and one pressure section or is it 3 scavenger sections? Probably either way you don't have enough scavenger pump to be able to get the engine case into a vacuum. You either need to add more scavenger sections or a vacuum pump. Most of the systems that are used to reduce engine case pressure by using the drysump pump will have 4 to 6 scavenger sections and they are of the geroler style pump which is much more efficient at pumping air/oil mixtures than the common gear pump. The presure section will usually be a gear pump. Look in this months "Hot Rod" page 98 there is a cutaway of the new Chevy NASCAR engine check the dry sump pump out, 5 scavenger sections. These are typically set up that one section is connected to each set of cylinders in the vee and the fifth section probably scavengers the heads. You can't see it in the cutaway but each of these sections are sealed from each other. There is big horsepower in doing this, much more than it takes to turn the pump. The F1 guys have been doing it for years and with all of the F1 engine tech that is going into NASCAR today it was only a matter of time.

Do not try to run high case vacuum with a regular wet sump engine. I know that the vacuum pump makers say that you can do it and maybe on a drag engine the only runs 10 seconds you can get away with it but on an engine for Bonneville that may be at WOT for several minutes you are looking to throw rods and spit out cranks. The only thing that makes the oil in the pan go into the oil pump inlet it the differential pressure between the pressure in the case and the vacuum that the oil pump can make. If you get the case vacuum high the oil pump will start to cavitate and bearings will begin to turn blue which proceeds other life changing events.

Rex

[jimmy six]

Sorry to differ with you Rex but I've been running a wet sump system for many years with a vacuum pump. I started back in 1994. Granted it had a learning curve but I never hurt an engine bearing or any thing. I started with a converted "smog" pump turning at 1/3 engine speed instead of the 1/2 half Stefs was using on the drag cars. I copyed what the "Econo" dragsters were doing at that time. Some actually ran a Holley jet in the suction line to keep from too much vacuum. At that ime Is a stock oil pump.

I have since gone to a side throw pan, 2 scrapers, an external oil pump, Moroso vacuum relief, and an Aerospace Products pump. The key is to slow them down. At this time at either Bonneville or El Mirage I have 7" of vacuum on the engine.

It can be safefly done......Good Luck JD

[Momec]

G'Day Guys
I'm new here but I do race in Australia on Lake Gairdner.
In my everyday job l work with dry sumps.
We run Daley 5 stage pumps and try to pull as much crankcase vacuum as possible (20 to 23 inches) This does allow very low tension rings.
As has been mentioned we also run a vented breather tank beside the oil tank in the boot but then run a small electric pump to return oil from the breather tank to the Petersen tank. This eliminated the puke problem and allows us to run high tank levels if required for endurance races.
Beware 23 inches is a lot of vacuum and there are some piston pin oiling issues you must deal with if you run this high.
See'ya Momec

[Dynoroom]

Hi Dave, The question you’ve asked is a good one but to answer it requires many more questions regarding the rest of the system and its components. Dry sump oiling systems have been in use for years so theres no reason you can’t run one to. But its important to know that pulling a high vacuum in the engine is not always a good thing depending on the way the engine is built and the application. 11”~12” is what is used by most endurance race teams. Some drag guy use more but the point is it requires other things be done to the engine like wrist pin & valve spring oilers, special lip seals etc. The real power improvement comes from the use of very low tension rings. The oil tank can be a problem too. Just too much to list here without direct interaction. But in the end it’s not hard to do.

My number is listed on my web site, give me a call and I’ll go over it with you if you like.

[Dave Haller]

Thanks very much for the great input. The pump is one pressure, two scavage. I'll give you a call and we'll talk,
Thanks again,
Dave Haller

[panic]

Do any of these systems have a simple relief valve keyed to case pressure?

Normal op: pump runs under load, pumps case down below ATM.

Trigger event: case vacuum reaches pre-set limit, Hobbes NC switch (sender can be anywhere if ported to case - valve cover, pan etc.).

Alt op: switch opens solenoid "T"d into the suction line from the case to the pump inlet, which admits (filtered) external air. The pump uses less power since it's not drawing against a vacuum, and the case pressure rises (due to blow-by, thermal load) until the switch closes when the trigger event is reversed. If air went right to the case the pump load would never drop.

Revert to normal: solenoid closes, shuts off bypass air, pump is now loaded to case vacuum. Fastest response: big connecting hoses, switch close to pan.

If you had a data logger with an unused channel you could plot solenoid cycling against RPM and MPH, but even an indicator light would tell you if the pump is too big, running too fast etc. (light is on too much).
Not only would this prevent losing bits due to lube failure and get back a tiny bit of power from the pump drive, but potentially tune in your pump speed (or capacity) without fraying your nerves. Even using quality parts I'll bet it could be done for $50.

[hotrod]

You might want to call Peterson Fluids and get their input on what you want to do.

http://www.petersonfluidsys.com/tech_faq.html

They used to have a vacuum limit device you could set the maximum crankcase vacuum with, but I have not found it on their site yet.
If you have any questions Mike or one of his tech people can help you out in designing a system.

Ahh here it is along with a pressure pop off valve in case the crankcase gets pressurized.

http://www.petersonfluidsys.com/engine_breath.html

Larry

[jimmy six]

You will notice I use a Moroso vacuum relief on the Areospace components pump in my pict and explanation. I understand the NASCAR engines also run with a high number of inches of vacuum. JD