Hey guys


I wanted to get some opinions from our local experts on venting the stock valve cover.

I have always had serious issues with oil flowing out of the breather on the front of the valve cover and blow by from the PCV. A lot of this has to do with the fact that there are more long, sweeping, right hand, high G turns at my local race tracks. My theory is that the the oil is standing up on the walls of the valve cover and eventually being forces out the breather and the PCV via blow by. In a 20 minute session it's not uncommon to loose about a half of a quart of oil! In one day I'm wasting a good amount of oil (2-3 quarts sometimes) form this blow by and thats an extra $20-30 bucks a day that I wouldn't have to spend if I was able to resolve the problem.


What I'd like to do is cap off the existing breather and PCV and weld a single -12AN bung to the opposite side of the valve cover (most tracks run CW so there are more sweeping rights than lefts).


My question is..... Will a single -12AN line to a dedicated breather provide enough venting for the entire system?

Do you guys have any suggestions as to where on the valve cover I should have the 12An bung welded? I think it might work best and help prevent oil flow if it was on the angled part instead of the side (since the motor is already leaning that direction by about 12 degrees) and possibly towards the back since there are way more Gs in braking than acceleration (I always seam to get the most flow going into a braking zone right after a right hand sweeper).


I will be running a much bigger breather / catch can where the battery was. The goal is to altogether eliminate the oil flow and provide adequate venting for the motor. BTW this is an NA F20C.


Once I get it all done I'll post pictures of the set up and keep you guys up to date on if function.


Thanks,
Rob

 

i keep meaning to build my own catch can, the ebay ones are fine, but i just like building my own stuff.

as far as the fittings go i'm in the same boat as you, i was gonna tap 2 -10 in the front and put the catch can on the front beam, however under hard braking, esp with me doing a lot of autocross i would be dumping oil into the thing.

bump for interest

 

If you vent both of those ports on the valve cover to the breather and cap the intake manifold port and the intake tube port that should be enough. With this setup your catch can should have at least three ports if not four. Two ports for the two hoses from the valve cover and another two for some little breather filters to catch the oil mist so your engine bay stays cleaner.
You should end up wasting less oil with that setup. I would only do this on a track car though because you won't pass smog like this. BTW with this setup you don't end up loosing any power by making your engine burn oil.


My setup right now is I just have the pcv port blocked and I'm venting out the front port in to a catch can with some metal mesh to trap as much vapor as possible and then that goes back to the intake tube between the throttle body and air filter.
I still need to put a gauge to see what my crankcase pressure is but I think it should be fine, if it wasn't then I'd most likely pop the dipstick up which I haven't yet.

 

That is the correct and best way to do it. Just make sure the Catch Can you choose is a good one and has internal baffles. Some don't and rely on the change in temp inside the can. Those are a poor design and nowhere near as efficient as the internally baffled ones. Mocal produce a nice tank that has a breathable cap which reduces/stops the hot oil smell. You could also modify the tank so as to avoid frequent inspection of the oil level and draining of the catch tank, you could install an automatic drain back into the sump.
Oh and you will really want to use a minimum of a 2ltr tank

 

Have you guys looked into an air/oil separator....not sure it works with our cars well but it's pretty popular in the subaru world as a better alternative to a catch can.

catch cans/pcv/etc are still one of the things I don't fully understand.

 

I've tried every possible configuration using the breather and PVC but still experience a massive amount of oil flow. It's is not simply vapor. The oil is standing on the side of the valve cover during high G turns, working its way into the baffling, and then flowing out the breather and PVC.

What you guys have suggested is exactly what I've done and that is the problem that I want to avoid. I think it has everything to do with the location of the breather on the valve cover and the fact that the majority of turn on CW tracks right handers.

This is squirrels2k's car and I'm looking at doing something very similar.

 

The other option is to drill a couple of drain holes in the baffle so that once the oil does buildup in there it has a place to drain back down before getting sucked up.
There's a pocket towards the back of the baffle for the pcv section, you can drill a couple of holes there to allow oil to drain out of the baffle.


A boosted car will need a setup like that and sometimes more than that but I doubt an NA car needs anything like that unless you have ring problems.

 

Honda has changed the position and the design of the PCV with the Facelift. The Valve Cover has been redesigned because the oil in the valve area is collected in right turns in an labyrinth area in the valve cover. The old PCV sucks the oil out of this area like a vacuum cleaner. This is why a lot of S2000 are heavy smoking in right turns when in VTEC.

The new design of the valvecover and relocation of the PCV has solved a lot of this problem, but not all of it - of course. Keep in mind that during VTEC a lot of oil spray is injected inside the Valve cover.

 

^ Yeah I plan to weld close the old PCV opening and possibly the front breather as well.

 

This is cool, but it doesn't appear to have a drain line heading back to the oil pan. Shouldn't there be one?