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I’m getting blow by and would like to remove the “gotta drain the can” step. 200 miles of clutch break in “no spirit” driving produced approx 1/4 cup of “caught” oil.
I was recently on a car rally and a guy with a ridiculously high horsepower GTR showed me his auto drain catch can set up that drained into the dipstick. They had TIG welded a small fitting on it so that the line could have a simple quarter inch drain from the can.
I’d like to do this on my setup. What’s the downside? When I drain I’ve never received any water/fuel mixture so I’m not overly worried about contamination. In fact I just dump it down the oil fill. Do I have to worry about the vacuum of the catch can sucking oil up the dipstick on cornering? Do I need to put in a shut off valve to open to the dipstick?
If I'm understanding what your asking, you would need a valve in between the catch can drain and dipstick tube plus the catch can would have to be higher than the dipstick tube to gravity drain.
Simple physics, put the can higher than the place you want to drain it into...because gravity.
I wouldn't drain a catch can into the motor. It's not just oil.
Weld a drain plug to the bottom of the can with a nipple on it, place a rubber hose over the nipple and route the hose down through openings at the bottom of the car. Put a drain pan under the car and open the valve to drain the catch can.
It kind of depends on how you drive. In normal driving I'd say it collects 1/4 cup over 1k miles, but if you do alot of spirited driving or sustained high rpm driving such as track usage you could get 1/4 cup in 100 miles or less. It's a fairly large reservoir that'll hold almost 1 cup of oil. I installed mine after installing new intake gaskets and cleaning my intake manifold and TB. It's amazing how much oil gets sucked back into the intake through the PCV system.
Yes OEMs have run separator systems. I have read on LS motors since they hit the market and some have tried to adapt one that drains back to the pan. However, even if they were engineered well I would prefer to drain the catch can as you keep an eye on how much it is collecting. If it started collecting more than is normal, you have an idea if something is going wrong and as posted above they shouldn't collect that much.
This actually is a pretty helpful thread. I would not drain back into the motor but my catch can is a bit of annoyance when I need to empty it, BUT if I had one of those drain lines that hangs off my Vortech V3Si that would be freakin awesome. Now I have to see if it will screw into the bottom of my catch can and how to procure one. I know any drain line would work, but I like the one Vortech uses...
Yeaaaa, I'll stick with my $100 Elite Engineering can which does not need a filter element to be replaced.
Catch can simply cools vapors and condenses them into a liquid. Only way to know if one can is "better" than the other is to run multiple cans in series to know if the first one is collecting/condensing all available vapors....oh and test conditions/rpm/motor health are all factors.
Some work better than others due to design and amount of steel wool type media available inside the can, which becomes a packaging/aesthetics challenge.
Never a BAD idea to add a catch can to ANY motor. My C5 has a EE can, my wife's 08 Lexus IS 250 has a EE can (notorious motors for carbon buildup on backside of the valves) and our 03 Silverado will get a EE can.
I appreciate the feedback. I'm going to keep it as it is since there is a butterfly drain valve at the bottom of the can and it's relatively easy to access. Hadn't really thought of contamination associated with misc vapors and hydrocarbons etc.
Catch Can drainback.
