How exactly does the CCV system work?

[blackdogvan]

So how do crank case gasses move through the stock system? The theory I have is the larger plastic hose from the block to the valve cover is large to reduce gas velocity allowing oil to fall back into the engine block through the side flange beside the vac pump.  I'd like to hear theories & science as to the CCV.  What I want is a perfect CCV system that puts zero oily mist back into the intake but need to understand exactly how the gas & oily mist moves in the stock system in order to make it work perfect on a 50 degree install.

[8v-of-fury]

Increase the size of the pipe, and make it do a completely verticle stretch before passing through some sort of mesh to catch the oil vapor?

[blackdogvan]

Yes increasing the pipe size & a mesh to give the oil mist something to settle on are high on the list.

[blackdogvan]

Yes I did & there are options out there, I'm trying to get more info on the actual flow path of the stock system to make a better mousetrap as VW intended. I don't think it's as simple as CCV gas goes up from the block to the puck where oil is caught & returned via the valve cover.

[RabbitJockey]

the air mostly does just that, it also flows up through the oil drain holes to the head

[rabbitman]

Yup, any air that is forced past the rings has to get out somehow and the only option is up through the oil drains into the vc area.

Running a breather from the cover where the vac pump vents up to tee in with the regular breather would probably help too. Didn't some come like that?
I saw a spearco pickup that had that but didn't know if it was stock or part of the turbo kit.

[RabbitJockey]

yes vw made a breather like that for on the 1.5 and 1.6, i made one on my old rabbit that i had blow by and run away issues with, completely solved both problems.  also any of the newer engines aaz-tdi all came a breather from the front of the block up to the hockey puck thing

[R.O.R-2.0]

Yup, any air that is forced past the rings has to get out somehow and the only option is up through the oil drains into the vc area.

Running a breather from the cover where the vac pump vents up to tee in with the regular breather would probably help too. Didn't some come like that?
I saw a spearco pickup that had that but didn't know if it was stock or part of the turbo kit.

it was a factory upgrade..

[blackdogvan]

It was a factory recall on the NA's as the breather was spraying oil onto the filters & afer long enough they would run away.

[RadoTD]

What I want is a perfect CCV system that puts zero oily mist back into the intake

What you need is a catch can! Good DIY here. http://forums.vwvortex.com/showthread.php?3248273
Same concept as the Doc's auxiliary separator but a more common way of doing it. If you buy a good baffled catch can, you're all set, but if you get a cheaper ebay one, I'd fill it with steel wool to help catch the oil vapor. If you really wanted to, you could drop the oil back into your oil pan, but personally I'd just empty the catch can every oil change.

[fatmobile]

I turboed a 1.5,.. with the smaller return hole in the block.
 The block pressure was causing oil out the turbo,
 and it soaked my airfilter with oil  because with the gasser Rabbit airbox the CCV  goes to a port on the far end of the filter,.. so gasses travel the full length of the filter,.. just soaked it.

  I used the puck with 1 exit,.. TD style.
 Used 3/4" silicone hose (it fits the TD puck) to go to a "T" coming off the blockoff plate by the vacuum pump,
 going to an oil seperator from there, still 3/4".
  So block pressure doesn't even have to go through the head, but if it does; it's vented to the front of the block where it's on it's way to the oil seperator, then the airbox.
 The filter looked clean last time I checked,.. but I haven't checked for oil entering the intake.
 

[blackdogvan]

I'd perfer to completly understand the stock system & make it better than add a catch can. IF its as good as it can be then its catch can time.
R

[8v-of-fury]

Most of the time, VW did it right the first time.. Some minor stuff that you think to yourself "what were they smoking".. But I mean engines have lasted a million km's with the stock engine and its components.. To upgrade it now would only benefit your peace of mind.

If its blowing enough oil in to the intake to scare you, then its tim for a rebuild. OR a catch can band-aid fix

[blackdogvan]

Project breather optimize is a sucess, negligable oil going into the intake & no catch can required. Stock CCV puck is now level & directly above the sump CCV flange, head's attached to the old side inlet spot & exit is normal. I did get a brilliant addition in the form of a Mercedes CCV spiral oil catcher thingy that sits below the puck in the block line. I'll post a pic if anyone's interested, any other happy 50 degree installers have a good CCV solution?