Evac pump pulls excessive amount of oil
 

I pulled a quart of oil through the evac pump during a recent autocross in just two runs. See picture for my set up.

I have a 3/4" spacer under the factory covers for total of 3 1/2". The bottom of the Moroso breather is 3" from the rails.

I can switch to a 3 3/4" cover and move the pick up point higher. Do you guys think this will solve the problem?

I didn't realize how much oil pools in the heads under high RPM.

455 w/ 4.25 stroke / .060 overbore
Kauffman heads

Attachment 518242

Sorry I don't have an answer, but that engine and engine bay look absolutely beautiful. Super, super clean.

How much vacuum do you have it pulling at peak rpm?

Usually 10-12 inches is all you need.

Do you have an adjustable valve on the pump? I can't tell in the picture.

Thanks. It didn't look to good after blowing oil out of the catch can breather all over the firewall and headers!

According to GZ, it pulls 19"-22" at 3500 rpm. I don't think it's adjustable, but would it make a difference if oil is pooling at or just below the breather?

That sounds like a lot.

You can purchase a separate restrictor to adjust the vacuum.

https://www.gzmotorsports.com/relief-valves.html

I don't know that it is the oil "pooling" in the cover as much as there is a bunch of oil splashing around and therefore mist.

I can't offer any suggestions beyond that, as I am struggling with the same thing (only a quarter mile at a time). I continue to play around with added baffling, gortex filter media and dropping the total vacuum at high RPM.

K

Make a thin sheet metal perforated Baffle that is 1/2" tall and epoxy it under the breather.
This is what I have done at times, also you might make a restrictor that goes in the pumps suction line.

That is a lot of vacuum..mine only pulls about 12 at full throttle. You will need some sort of regulator, they do sell them to go in the other valve cover and will open up at a set level. My valve covers are just the cheap Mr Gasket style with their baffle as well as their valve cover vents. I also use restricted pushrods to limit the flood of oil up top. I drive 200 miles roundtrip to the track do 8 hard passes come home and maybe have an ounce of oil in the can.

Ah....yeah that's a lot. Pulling that much will fill the catch can in no time flat.

You're going to need a regulator to turn that down. They mount on the pump where your hose connection goes to the valve cover. What ever your peak rpm is you want maybe 10-12 inches max at that rpm, and the rest will take care of itself. Once adjusted, usually light throttle cruise will see 3-4 inches of vacuum.
Once set like this it'll go 200-300 miles before you'll have to drain the small catch can that holds about 8-10 ounces in our case.

On a side note, pulling as much vacuum as you're pulling is said to pull oil away from critical areas like wrist pins and can cause failure. However you want it pulling some oil, that's how the pump lubricates itself. If you aren't pulling at least a few ounces after a couple hundred miles, then according to instructions you have to add oil to the pump on a regular basis, which is a pain in the butt by the way, lol.

I'll reduce the vacuum before I relocate the pick up point or consider restricted push rods. It's certainly the easiest, most cost effective solution.

I convinced myself there was a big pool of oil in there. I never imagined 60 seconds or so of high RPM could pull that much oil mist. Glad I asked, and thanks for the suggestions.

Are you running a dipstick?

Yes. I'm running a dipstick.

That's part of your problem. The motor needs to be sealed

Pull dip stick tube and put a vacuum cap on it. You need the regulator to lower the vacuum. You have to much.

Just curious what oil pump are you using?

60 lb oil pump w/ a shim.

I'll cap the dipstick tube and test for air leaks.

The one here has a dipstick and it works perfectly fine.

I would guess if you have a dipstick that the seal for the stick is non existent then it could be an issue.

Check where the tube gets pressed into the block. Mine was leaking there and by the valley pan.You do not need a lot of air pressure when checking. 10psi max.

Wouldn't a dipstick be a leak point and cause lower vacuum, not too much?

The leak point at the dipstick actually will make the pump pull harder to compensate for the vacuum leak which can result in excessive oil being put into the catch can.

I am reading to learn I don't really think I need this . The one question I have is , sorry if this is a stupid one, why can't you just return it to the oil pan like they do with turbos?