Excessive oil through PCV

[corey_dyck]

I'm getting an excessive amount of oil through my PCV valve into a catch can at autocross. Not a drop on the street though! The little catch can (shown below) is pretty much filling every 55-ish second run, it used almost a quart in 8 runs on Sunday!

Car: 2001 S2000 in A-Stock. Gendron front bar, Hoosier A6 245/45R16 all around.
In car video, me: http://www.youtube.com/watch?v=ESYH71xAeiQ
My co-driver: http://www.youtube.com/watch?v=BOUGOZWvJio

Any thoughts on what might be wrong? Another S2000 with a similar tire setup has minimal smoke out of the tailpipes except on long braking zones into tight right turns.

Here are some details on the catch can, from a thread I posted on another forum:
Here's my budget catch can install. I took this guy's idea and modified it slightly: http://www.pbase.com/rsrock/oil_catch_can

I haven't had a drop in the can yet, I think you need higher G's than I can get with my street tires to make the oil pool in the front of the valve cover.
Here's mine. Left side of picture, just in front of the shock tower:
http://i28.tinypic.com/29yrpt2.jpg
The lines run behind the airbox and up between the valve cover and the intake manifold.
http://i25.tinypic.com/svgzus.jpg
http://i25.tinypic.com/4gj9f9.jpg
http://i32.tinypic.com/1r9lee.jpg

[Coop]

I think the valve cover was changed in the AP2. I know of some people who have done a mod on their AP1 valve cover.
The valve cover has a plate to keep the oil up in the valve cover, drilling some small holes in this plate to let some of the oil to drain back into the head.

I know of one person who did this, and it took care of his problems.

[repiv]

Some cars do this to the extreme. I don't think your situation is particularly abnormal even though it may be at the higher end of the range of oil movement out of the PCV system. Because of where the PCV outlet is, most of the oil ingestion happens on hard right turns. That's where the "slosh factor" is the worst.
From your pictures, it looks like you are also using a "closed" catch can system. That is to say, you are using manifold vacuum to suck the vapours out of the PCV outlet. This can greatly exaggerate the problem. However, if you didn't actually catch it, all of that oil would have gone into your combustion process and you would see that in the way of blue exhaust smoke.
It's not that there's anything wrong as such. It's just that the catch can system you have, is making things noticeable and measurable.
There are solutions. COOP's is one such option. You do the mod to your valve cover to minimize the oil pooling at the PCV outlet. The holes will drain the oil away quickly so that much, much less of it will go thru the valve and into your catch can.
Another option would be to go to an "open" catch can system. This is where you have a vented catch can with only the hose from the PCV valve going into it. You plug the hole left at the intake manifold. This way, there is no vacuum to suck the oil out and only true crankcase pressure will force the oil out. Generally speaking, this pressure has less effect on oil movement out the exit than would the vacuum created in the manifold, especially on heavy engine braking where the throttle is closed at high rpm.

[corey_dyck]

Thanks guys! I actually can't modify things beyond the stock parts in Stock class. There is a rule specifically allowing catch cans though, but I can't change the flow path of the PCV air without risking a protest.

I guess the next step is getting/making a bigger catch can so that it doesn't completely fill/overflow in one run.

Out of curiosity, what does the baffle plate on the underside of the valve cover do? Picture of it: http://www.pbase.com/rsrock/image/34843731 It looks like a convenient place for oil to pool that's being splashed around, but what's the point?

[repiv]

I'm not positive what Honda intended for this baffle to do, but if you've ever run an engine with the valve cover off, you will notice just how much oil splashing goes on under there. The baffle may have been put there to minimize the oil splashing towards the PCV and front breather holes and getting prematurely sucked out. After all, the PCV system is mainly for removing pressurized vapours and not really for liquid oil. Unfortunately, under high lateral G loading on a right turn, a lot of liquid oil is sloshed up and above the baffle where it sits there longer than it should. The intent and purpose of the baffle is a good idea but the design may not have been thought out thoroughly enough.

[corey_dyck]

Makes sense since it's nearly sealed on the PCV side and open on the other side.

[gomarlins3]

Hey Dave, would Krank Vents help this?

http://automotivespeed.com/product_info.php?products_id=304&osCsid=301ec655ef1e2892d22858686e99e9ff

http://automotivespeed.com/product_info.php?products_id=49


Just a thought.

[repiv]

Hey Dave, would Krank Vents help this?

http://automotivespeed.com/product_info.php?products_id=304&osCsid=301ec655ef1e2892d22858686e99e9ff

http://automotivespeed.com/product_info.php?products_id=49


Just a thought.

It might. Certainly, the valve in a Krankvent is much stronger than the one inside an OEM PCV valve and thus may take more vacuum to open it. However, I'm not sure that this would make a noticable difference since the only oil that it might prevent from going through is that which is forced through by crankcase pressure. I've heard comments from those with NA engines that KVs do help. Initially, one would think that they are best for FI applications, to prevent boost pressure from going the wrong way (into the PCV valve).