Air Oil Separator

[jwilkinson01]

I hope this doesn't belong in the Newbie section as that is how I still think of myself, but it seems like a little more advanced of a topic.

As I slowly collect parts for my rebuild and think of ways to build the most reliable motor possible, I have been thinking about running an AOS. With the increased compression and the idea that I might like to add a supercharger someday, that will increase the possibility of blow-by, it seems like it can't hurt, plus I have never been good at leaving well enough alone. I know there's a few people with catch cans, but I mean a true AOS with a return to the oil pan and a heater to keep moisture from the sump. I think SilverXJ might have one but my search-fu didn't turn up much.

The problem I have is figuring out how plumb everything. I contacted the manufacturer of the particular universal AOS I am looking at and what they are telling me doesn't make sense to me. I know they should be the trusted source, but they are used to working with much different engines, like whatever comes in a WRX STi with a PCV system, not the old 4.0 inline 6 with CCV. And I am definitely not an expert by any means, so there is a lot of room for error on my part.

The line to the oil pan and the water lines are easy enough. But for the remaining lines I need help.

So after quite a bit of digging I think I finally found out how the CCV system functions. It works in a loop, the suction comes from the intake manifold itself. So fresh air is drawn in through the air intake tube into the first orifice which is wide open, mixes with the crankcase vapors and is then drawn out the second orifice (rear of engine on my TJ), which is a metered orifice controlling the amount of airflow, then to the manifold where the vapors are supposed to burn off.

Crude, homemade drawing #1 (hopefully I add them right):

CCV.jpg

To my brain I want to place the AOS between the rear tube and intake manifold.

Crude, homemade drawing #2:

AOS1.jpg

But the tech support guy that emailed me after I used their contact form is saying to cap the intake manifold, run the line from the intake tube to the AOS and cap either of the tubes coming out of the valve cover or Y them to the AOS.

Crude, homemade drawing #3:

AOS2.jpg

I just don't understand how it would work without the suction from the intake manifold. Also this no longer seems to be a loop. I do know the line to the oil pan (which I have not included in any of the drawings) will allow for additional ventilation and maybe that's why it works the way they are telling me? I definitely don't want to do it wrong and either gain nothing or possibly break things.

If anyone can point me in the right direction here I greatly appreciate it.

Thanks
J

[Cheromaniac]

On a naturally aspirated engine, drawing #2 is the correct set up.

[unlimitedrubicon]

Here is an article that you may find helpful.

http://www.radiumauto.com/Webpage.aspx? ... PostID=102

[jwilkinson01]

On a naturally aspirated engine, drawing #2 is the correct set up.

Thanks Dino for the fast response. I feel a little smarter knowing you agree with me!

Here is an article that you may find helpful.

http://www.radiumauto.com/Webpage.aspx? ... PostID=102

And thank you as well Unlimited. That article is very helpful.

So it looks like I can put the AOS in line either between the Intake tube and the front opening on the valve cover or between the rear opening and the intake manifold. I still feel the between the manifold and rear valve cover tube will be best, so I will put it there but I will keep an eye on the intake tube to see if I need to swap the hoses. Then I will have to rethink it all when/if I go forced induction.

It's funny to me that the article you found is from Radium as that is exactly who's tech support I was talking to that told me to cap off the intake manifold port.

Thanks again everyone!
J