DRY Sump Venting

[Allan]

What is the correct way to vent a dry sump?
The vent line now comes from the top of the sump and loops straight down, but we keep loosing oil when filled to the bottom of the baffle plate. New motor, back pressure OK

[Superfab]

You need a vent tank mounted higher than the dry sump tank. Peterson fluid sysyems makes some nice ones.

[pdailey]

-16 line up and around the other side of your car. Straight down to the ground. That's all you need.

[ffjerm]

I like the idea of having a breather with a small catch can below it. Peterson sells them. The best method I've found is to mount the breather about 10-12 inches above the tank, though I've seen them higher and lower. pull the drain plug out of the bottom of the catch can and tap it for a barbed fitting. Run a 3/8" line off this fitting out the bottom of the car. I've found that with a long hose running up and around the car, the oil trying to return to the tank decreases it's ability to breathe. Also, the bigger the breather line, the less oil will be lost out the breather...-12 should be the minimum.

Remember to keep the breather away from the headers....in the unfortunate event of a top end failure, oil will exit the breather....fire follows.

good luck!

[Allan]

Thanks for the suggestions. Found the promblem. Both the vent line and the line that brings oil back into the tank were mounted on the top of sump. Moved main oil line down 3" below foam filter & no more blow by.

[fashionbiff]

I like the idea of having a breather with a small catch can below it. Peterson sells them. The best method I've found is to mount the breather about 10-12 inches above the tank, though I've seen them higher and lower. pull the drain plug out of the bottom of the catch can and tap it for a barbed fitting. Run a 3/8" line off this fitting out the bottom of the car. I've found that with a long hose running up and around the car, the oil trying to return to the tank decreases it's ability to breathe. Also, the bigger the breather line, the less oil will be lost out the breather...-12 should be the minimum.

Remember to keep the breather away from the headers....in the unfortunate event of a top end failure, oil will exit the breather....fire follows.

good luck!

Question, why drain the oil off the car from the catch can? Wouldn't you want to drain the oil back into the sump? I am asking because I obviously don't know but it seems oil is kinda important to keep around.
The only thing I can see is expansion in the sump limiting the amount of oil? And if so wouldn't you still run a breather with a catch can having two lines. The bottom draining back into the sump and one higher on the catch can to drain off for thermal expansion? I am assumming a completely full sump and oil just cycling up the breather line which is not going to work right?
I guess my two line tank would have to be a breather tank with line running down to a seperate catch can that is just above the oil sump bottom line drains into sump and top vents out. You need a one way valve to keep the sump from pushing the oil back in.
I am overthinking this I guess. :p

[ffjerm]

It's a very minimal amount of loss, probably don't even need to run the drain line. Only time we ever had a problem was during engine failure.

[Allan]

Fashionbiff, Back presure from the motor is vented thru the sump, at the top below the oil line. You need a vent line coming out of the sump to releave presure.

[robertharman]

I used to have the breather fo rthe motor mounted higher , ran the vent line from dry sump tank to engine breather,and a return line from bottom of breather to back to dry sump. Zero loss.

[FISHMOUTH FABWORKS]

my vent can is around 6" below the top of my tank. -12 for all the oil lines and -10 to the vent can. been running 8qrts in my BBC seems to work ok. how much do you guys run?