Valve cover breather?

[KCz Eclipse]

Okay, so I've been looking at some pictures of 4g63 engines. While looking at the pictures I noticed many of the people had removed the tube on the left side of the valve cover and replaced it with a thing that looked like a mini filter. So with a little research found out it is called a valve cover breather. However, I wasn't able to find the purpose of the breather. So for my question; what is the real purpose of the breather? Could oil leak out of the breather at all? Is there a plus to using a breather versus the normal tube? I just think they look cool, and if they don't have any real cons, would like to get one. Any info on these things would be helpful.


Thanks

[rcarbajal4]

They are also catch cans. The hose returns some of the oil caused by crankcase pressure back into the intake pipe. So the purpose is to clean up the engine bay, intake, and help the engine run better in general. And yes they look nice

[Gstclipse69]

People use the valve cover breathers because that line can let oil back into the intake, coating the intercooler pipes with oil over time. It does serve a good purpose in not letting the oil back into the intake, however a better solution would be to add a catch can in the line going from the valve cover to the intake. Reason being, the intake acts as a vacuum, helping to pull air/oil out of the valve cover to lessen crank case pressure. Check out catch cans, and decide how you want to set it up. That will open a whole nother discussion.

[KCz Eclipse]

Well, with that said. What would you guys recommend/ what are you guys using?

[rcarbajal4]

Originally Posted by KCz Eclipse

Well, with that said. What would you guys recommend/ what are you guys using?

I personally don't have anything. But I am planning on getting a catch can. They sell them on ebay, from vendors, and a member on here, "calan", makes a good unit, as many here speak highly of it. I am planning on picking this one up:

http://www.ebay.com/itm/ADD-ANY-CAR-...-/200762354027

[KCz Eclipse]

Looks cool, but how would something that get setup? Looks like there are two places to put pipes, where does the second one come from?

[954g63gst]

you run a hose from the valve cover to the catch can then the second hose goes back to the intake where it was when stock

i go to auto zone for the cool red breather filters ive got one on my egr blockoff and valve cover

[mantega4g63]

The 4G63T PCV System

This will answer all of your questions on the pcv system (What you are seeing is breather filters on the pcv breather side which should be routed back to the intake (preferably with a catch can in between), so excess blowby from the combustion cycle can be reburned which is just better on the overall performance of the car)

[gofer]

Read (thoroughly) and if you don't understand it, read it again.The 4G63T PCV System

Craig (Calan) does make a nice catch can, however, if you're just trying to catch the oil before it makes it's way back to the intake track on a stock setup I recommend doing these (2) things.

- Install this on the line running from the valve cover to the intake Install a catch can for your DSM (2G)
- Following Craig's write-up that I linked to, install one of these between your PCV on the top of the valve cover to the intake manifold port. 3/8” Kynar Standard Check Valves

Running a nice catch can setup, especially in a stock engine bay with cruise control, A/C, emissions, etc., it can be tough to find a good place for it and it isn't really necessary which is why I'd recommend the above.

EDIT
Damn. Typed too much and mantega4g63 beat me to that PCV link.

[boost97gst]

If you put one of those neat little filters on your valve cover its going to get unmetered air. The vac at idle and cruise will pull air straight throught that filter and right through the pcv. Its not a good idea.
Run a catch can if anything or if you want that filter deal i would make sure theres a check valve in it, otherwise it wont run right

[bryanwheat]

Originally Posted by 954g63gst

you run a hose from the valve cover to the catch can then the second hose goes back to the intake where it was when stock

i go to auto zone for the cool red breather filters ive got one on my egr blockoff and valve cover

A filter on the egr block off, how does this work?

[KCz Eclipse]

Does anybody know of a decent catch can i can get and put on the same time i hard pipe my intake? Nothing to expensive though.

Thanks

[vl4bad]

i have a greedy catch can, it works pretty good, its easy to empty, and looks nice and simple...

[2skippy]

JM Fab makes small decently priced one. Check extremepsi.com

[mantega4g63]

Get an inline fuel filter from any parts store like advance auto. Go with one with a clear housing so you can monitor how much oil it collects. Install it between the intake and pcv breather port on the side of the valve cover. The filters run about $4 and work great, vacuum from the turbo pulls blowby through the little filter

[tinydancergst]

There's not much of a downside to the breather filters. My brother has one on his gst and I had one on my gst as well. They look very cool and clean up the engine bay nicely.

[Calan]

Originally Posted by mantega4g63

The filters run about $4 and work great, vacuum from the turbo pulls blowby through the little filter

...until they clog up and/or collapse; at which point you have no CC pressure relief at all.

Originally Posted by tinydancergst

There's not much of a downside to the breather filters.

Except for the film of oil that gets everywhere once they become saturated, the lack of negative pressure to help vent the CC, and the unmetered air entering the IM...

Yeah, they rock.

[mantega4g63]

Originally Posted by Calan

...until they clog up and/or collapse; at which point you have no CC pressure relief at all.



Except for the film of oil that gets everywhere once they become saturated, the lack of negative pressure to help vent the CC, and the unmetered air entering the IM...

Yeah, they rock.

They can clog just like any other catch can could, by neglect. Simply replace it with another $4 filter, or pay 100 for a good one. Theyre much easier to check too, of course id love a nice catch can but i have other priorities

[bryanwheat]

Originally Posted by mantega4g63

They can clog just like any other catch can could, by neglect. Simply replace it with another $4 filter, or pay 100 for a good one. Theyre much easier to check too, of course id love a nice catch can but i have other priorities

A filter isn't a catch can, it is a filter. A filter clogs because the filter material becomes saturated with oil and stops the crankcase vent system from doing it's job. A catch can is a can that catches the oil vapor to keep it out of your intake tract. As stated before it will also cause you to pull un metered air into the engine thru the crankcase and can cause your engine to run lean under vacuum.

[mantega4g63]

Originally Posted by bryanwheat

A filter isn't a catch can, it is a filter. A filter clogs because the filter material becomes saturated with oil and stops the crankcase vent system from doing it's job. A catch can is a can that catches the oil vapor to keep it out of your intake tract. As stated before it will also cause you to pull un metered air into the engine thru the crankcase and can cause your engine to run lean under vacuum.

Install a catch can for your DSM (2G)

This is what I'm referring to, not a breather filter, but a filter that allows circulation to the intake track

Originally Posted by steve

We know that you were talking about.

The problem is the filter media gets oil in it long before you see any oil collecting and once the media has oil in it, the air stops flowing and no more crankcase ventilation.

thanks for letting me know, now I know to get a ready catch can

[steve]

We know that you were talking about.

The problem is the filter media gets oil in it long before you see any oil collecting and once the media has oil in it, the air stops flowing and no more crankcase ventilation.

[Chrispy0530]

So, in a nut shell the Fuel Filter method is useless? This is how my setup currently stands, and if there is no relief, well I might need to look into another setup.

[PieEyedPiper]

Originally Posted by Calan

...until they clog up and/or collapse; at which point you have no CC pressure relief at all.



Except for the film of oil that gets everywhere once they become saturated, the lack of negative pressure to help vent the CC, and the unmetered air entering the IM...

Yeah, they rock.

Originally Posted by mantega4g63

They can clog just like any other catch can could, by neglect. Simply replace it with another $4 filter, or pay 100 for a good one. Theyre much easier to check too, of course id love a nice catch can but i have other priorities

Originally Posted by bryanwheat

A filter isn't a catch can, it is a filter. A filter clogs because the filter material becomes saturated with oil and stops the crankcase vent system from doing it's job. A catch can is a can that catches the oil vapor to keep it out of your intake tract. As stated before it will also cause you to pull un metered air into the engine thru the crankcase and can cause your engine to run lean under vacuum.

These posts sum it up very nicely. At first, I thought the inline fuel filter idea was fabulous. I'd tested them to last as long as an oil change with minimal pressure drop.
I was wrong. The pressure drop across these filters can often become significant after short use. The mouth test is fairly useless, too. Fast forward to today and you'll find that I have no such filter in place, but a catch an instead. Funny how as soon as I removed my inline filter (brand new or not) I stopped seeping oil from the oil cap all together.

[boost97gst]

Yup, even the grizzled old wisemen all agree, filter on your VC=bad. I suppose you could cap the pcv nipple on the mani, plug the pcv VC side and run large pipe from the side nipple to a good catch can then straight to the intake pipe preturbo. I think thats been done. I have yet to hook up my catchcan and still, zero oil in my intake pipe. Now the IM might be a different story... Im only running 12psi for now though so i guess ill see when i start pushing near 45lbs/min out of this pte.

[lowell]

Some good pics/ideas here:

Vented Valve Cover Post up some pics! - Honda-Tech

[mikesx4911]

That was one of my first mods that I did lol.

[Calan]

Originally Posted by lowell

Some good pics/ideas here:

Vented Valve Cover Post up some pics! - Honda-Tech

Even better ones on this site if you search... DSMs even!