Grabbed_Crow_Mobe

I am doing a LS6 engine build and am adding a dry sump. I have been doing a lot of research on dry sump systems and one issue that I can’t seem to get consensus on is whether or not to use an external pressure pump or internal stock (or aftermarket high volume Mellings) pump.

The dry sump manufacturers unanimously agree that an external pump is far superior for reasons outlined below. I’ve spoken with a few engine builders, fabricators and drivers who prefer internal pumps.

Below is a compilation of what I’ve found so far. I’d love any insight you have or whether my findings aren’t accurate. My current plan is to get a three scavenge line system and use an upgraded Mellings internal pump. The cost difference isn’t a big issue (as it’s not typically that much different depending on the vendor) as I want to do it “right”. Problem is that I can’t determine what “right” means.

Edit: This is for a dedicated race car. No need to retain A/C, etc.

Edit: Internal/External pressure systems are about the same price from both ARE and Aviaid

External Pump:
Pros:
No cavitation at high RPMs.
More control of pressure.

Cons:
If you lose the belt that drives the pump, oil flow stops and engine most likely is lost.
Can be more difficult to fabricate the install (depending on amount of scavenge lines) .

Internal pump:
Pros:
Since this pump runs off of the crank, it’s always spinning. If you lose a belt, you still have pressure.
Internal pumps rarely fail.
Easier to install.

Cons:
“less control” of pressure.
High RPM cavitation.

I’ll update my findings above with comments so hopefully someone else can use this thread in the future.

Painrace

Well, I have a few years of using dry sumps systems. I would go with and external pump if I was not going to have air conditioning. If this is a race car, definitely external pump. What you are missing is the scavage with the internal pump is marginal at best even with a Katech internal pump. Katech even recommends and installs an ARE external additional scavage pump.

You are correct you can adjust the external pump pressure which is a great advantage. In in 56 years of racing I have never had and external dry sump pump belt come off. I have broken them when the engine failed but never come off. Most external belts are adjusted too tight. They should be adjusted so the belt can be twisted 1/2 turn.

I recommend you call Gary Armstrong at ARE, 916-652-5282, and talk with him. Tell him Jim Painter told you to call him. Follow his recommendations on line sizes and installation exactly. Line size is very important. Get one of his new tanks and I would also install a Spintric.

Good luck.

Jim

Grabbed_Crow_Mobe

Thanks for the reply and insight Jim. And yes, this is a dedicated race car (original post modified to include this info).

I was under the impression that the scavenge pump (circled in red) is separate from the pressure pump (circled in blue) and is always external. From ARE's website:



I've talked to Gary at ARE and he was a great help.

Hi Volts Z06

I think the key is what RPM you are turning the engine. If you are going to be under 7,200 RPM the internal pump is fine and cavitation shouldn't be an issue. However, since you are doing a build with the motor out of the car, other than the additional costs, there really is little downside of an external pump.

flash911

^ I would agree with this. Also, an external pump creates a little extra vacuum which is free HP. If I was starting over or doing a system from scratch (I am for a new project), I'd get a Daley pan and pump with a Spinton or other air / oil separator system.

http://www.daileyengineering.com/ls_engines.htm

ARE, Aviad, etc all have internal pump oil control solutions which include pan baffles, aftermarket tanks and blueprinted pumps which seem to work very well.

Bink

Just a thought - Dailey Engineering http://daileyengineering.com/ls_prod...side_mount.htm

Screamin Z

The scavenge and pressure side of the pump are all in the same housing.

topmover

I have used two different external brands, stock LS7 internal, and ARE/Katech internal system which is what I currently have.

I had a ton of issues with my first external set up including a broken pump shaft which resulted in a total loss of oil pressure. Once I switched to an Armstrong pump it worked awesome although I always worried about the belt coming off...........I'm told you can wire a shut off switch if you wish.

I like my current set up as I don't worry about the belt however I've kept the motor somewhat tame.............. the Armstrong seemed to keep the pressure much higher later in a race.

For me if my car were a purpose built tube car with plenty of clearance I'd probably go with the Armstrong external regardless of the engine.

On a production built race car I would likely only consider the external if I were going with a high rpm or high hp build(over 500-550 rwhp)

Just my opinion as I'm no expert but do have some varying experiances.

JVetthead

Not too fond of internal pumps

Paul Schmidt

JVetteHead clued me in on the Dailey a couple of years ago. I had to have it. Great system and great support from Bill Dailey the owner Dailey dry sumps.

Here's JVetteheads awesome set up.



This is my setup on an LS3





I don't have motor mounts as fancy as his. I got these from Speed South to handle the clearance of the massive pump.


Finally getting finished up.

The Dailey is the best!

Painrace

It is one pump with 4 stages. One is oil pressure and three are oil scavage.

Follow Gary's information exactly. Vent each valve cover back to the top of the dry sump tank. Small diameter lines will do it.

Jim

Grabbed_Crow_Mobe

Thanks for the replies everyone. I haven't talked to Dailey yet, I'll do that soon.

Updated original post to verify that going with an internal pump isn't less expensive than getting an external pump.

JVetthead

The thing with the Daily pan is there are no external scavenge lines there are internal passages as the pump is attached to the pan.
So that means 6 less hose ends for potential leaks or failure

Grabbed_Crow_Mobe

Talked to Dailey today. Very trick setup indeed. Unfortunately, the most expensive option that I have found.

JVetthead

They usually have used units for sale.

yooper

Anyone figure out a way to adjust pressure on this pump after installed in a C5? The adjustor is at the bottom left of the pressure inlet in the picture.

Had I known, I would have drilled a hole thru the bottom of the engine support bracket to allow access from the bottom for adjustment.
The jam nut can be reached from the side.

Normally the pressure would be set while running on an engine dyno.

jimtway

I just reach in with a couple of wrenches from underneath the car. Its sucks, but its doable. FYI, I backed my regulator all the way to the minimum (lowest PSI) setting. We run 10-30w oil and are at 80 psi cold idle.

jimtway

Kevin, I would add to the con list or note for the 4 stage that you need to fabricate your own passenger side engine bracket. You also need to find a smaller diameter motor mount or go solid mount. The aft pressure in port sits right over the OEM mount location.

yooper

Thanks for the info on the adjustment. Do you have coilovers or a leaf spring?

Here is a picture before installing in car.

jimtway

Coilovers.