Stupid PCV question

[FORMONTOYA]

I've gone through 2 OEM PCV (read boost leak) valves in 1500 miles since the car came off jack stands December 05. I'm tired of buying and replacing them even though they are not that expensive. I was going to pull the nipple out of the intake and put a 1/8 BSPT plug in that location and use the nipple from the intake and replace the PCV valve, however, the nipple is a press-in fit so that's out of the question. I just capped off the nipple and used the PCV valve as my nipple to "T" into the vent line going to the intake before a G-2 gas filter (catch can).

My question is why do I have to hog out the PCV valve internals? There shouldn't be a differential pressure type of thing going on, therefore the PCV valve should remain open, shouldn't it?

Below is a half-a$$ drawing of what I propose and if someone can give me a legitimate reason why it should be hogged out, I'll just order a nipple for it.

 

[SimpleSecurity]

Awsome Thread, this saved me probably $100+ dollars. Ordered my check valve.

Only thing thats still kinda hanging for me is I bought my Intake pipe w/o a nipple for the VC breather tube. From reading through the thread from page 1 its not incredibly important to have that tube hooked up as gunk still gets blown out that tube without some kind of vacuum source. As of right now its just hanging down and gunking on the road.

Having a GM MAF im not worried about the air being metered as I cant put it back in so leaving it hanging i figured was a no big deal.

I am right to assume stuff still gets blown out the VC breather tube?

 

[TommyDSM]

Wondering if anyone used the check valves that were in the lines between the brake booster and the IM? If they held up well? I had acouple laying around and stuff them into a 3/8 line for my setup....

Also I bought a Autozone PCV and I can blow in it both ways... wondering if it should of sealed one way or if it had a spring and needed more pressure to close it...

 

[SlickPyro]

Only thing thats still kinda hanging for me is I bought my Intake pipe w/o a nipple for the VC breather tube. From reading through the thread from page 1 its not incredibly important to have that tube hooked up as gunk still gets blown out that tube without some kind of vacuum source. As of right now its just hanging down and gunking on the road.

Having a GM MAF im not worried about the air being metered as I cant put it back in so leaving it hanging i figured was a no big deal.

I am right to assume stuff still gets blown out the VC breather tube?

I was wondering the same thing as I am about to order a 2g maf intake pipe from dejonpowerhouse. Would it be fine to put the K&N Valve Cover Vent filter that they sell on their site on the passenger side of the valve cover. I plan on putting a check valve from usplastics inbetween the pcv valve (on the back of the VC) and the IM, but I do not know what would be most efficient on that vent on the passenger side of the VC. Thanks.

 

[Gstclipse69]

I have the dejon 2g maf intake pipe and the best way to hook this up properly is to drill and tap a thread for a fitting on the intake pipe. Its not hard at all. All you need is a fitting, drill bit and corresponding tap. The best way is to run the vc breather hose back into the intake but with a catch can. This way the catch can will catch any debris from the vc to intake and the breather will pull vacuum from the intake pipe.

 

[kawboy]

Just wondering the amount of oil you guys have been catching with the catch cans.

Also, wondering who's running a baffled or unbaffled can

 

[DSMunknown]

Depends on how long I go without cleaning it out. After about a month there's probably about a half to 3/4ths of an inch of build up on the bottom. But that's with the Husky. It depends on what can you're using. I am using unbaffled cans. When discussing catch cans, baffling won't do squat IMO.

 

[No_Skillz]

I'm running the husky compressor filter with filter element. I have maybe a tablespoon full of oil on the bottom. It's never been off the car nor emptied since I installed it almost 2 years ago.

Everyone's car is different. I have seen cases similar to mine and cases where the can needs to be emptied every week or so. It's not a reliable way to look for problems, nor is it necessarily symptomatic of a problem if you have alot of blowby.

 

[kawboy]

So I'd have no problems running a baffle-less catchcan?

I was told I need some kind of air/oil seperator as most of the oil passing through is Vapor.

 

[DSMunknown]

So I'd have no problems running a baffle-less catchcan?

I was told I need some kind of air/oil seperator as most of the oil passing through is Vapor.

Which is exactly why baffles don't make any sense in catch cans, especially between the IM and VC. You just need to find a really good filter. And an arrangement that will not leak. FYI, the first pix in the second link are my new cans. My old Husky cans leaked at the bottom.


http://www.dsmtuners.com/forums/hangout/301705-started-making-some-catch-cans.html
http://www.dsmtuners.com/forums/hangout/302732-why-i-love-aluminum-other-soft-metals.html

 

[PieEyedPiper]

Bringin' it back once more.

I've long since invested in a G2 filter and the USP corp. check valves. Really, I didn't have much a problem to begin with, but I'm the type who will try and fix it even when it's not broken.

Anyways, I've put roughly 4-6k miles on my most recent filter and valve and just checked my 5th (I've been replacing them periodically) G2 filter for the second time. The first time I could still blow through it without much resistance and that was at ~2k miles. Today I checked it again only to find that I could not blow through it at all. I've since stabbed it with a flat head to allow the passage of air/vapors again, but I'm curious, does anyone know the average life of these kind of parts? I'm just thinking that I was lucky enough to "just decide" to check it, but maybe it should be swapped with every oil change, or even more often in some cases.

I would imagine that it could potentially be dangerous for your engine if you were to leave those filters on too long. Who knows how long mine was like that. Also concerning is that I have noticeable puffs of air trickling out of the VC breather port at idle, so hopefully I've caused no grief since those "exhales" were certainly blocked.

I'll be removing my USP valve for testing later in the week. Who really knows how well those hold up to heat and oil over time...

Edit: The G2 filter looked fine, obviously used, but fine. Only a few drops in the casing. Thats all thats ever in there, however, the filter material was fully saturated with oil which is obviously the cause for the part to get all blocked up.

Edit II: I tested the USP check valve today and it was in flawless shape. Flows like brand new and it shuts up like new with roughly 7k of use.

 

[nicknorth11]

I wanted/needed to improve my ventilation from my valve-cover and sent it to jmfab to have (2) 1/2" barb fittings installed on the side that will be ran to a vented catch-can. I still want to have some sort of suction from the intake, so I figured if I got a reducing tee (1/2" down to a 1/4") sending a 1/4" hose to the intake it would work. I figure I'll have to connect the tee as close to the v.c. as possible to increase suction from the v.c. instead of the c.c. I also incorporated the check-valve and pcv into my system. Please refer to the picture below to see what I'm talking about.
(I'm also using a gm maf as blow-through).

Do you think this will work?

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[Calan]

You'll have unmetered air entering your IM when off-boost, and you're going to get oil in your intake because your "suction" is bypassing the catch can.

 

[nicknorth11]

I'm not worried about the oil in the intake. It will be negligable, as the path of least resistance will be the 1/2" line to the catch can. Also, there will be a 90 degree turn to enter the intake's line. I wonder how much the unmetered air will affect things. I don't think much, but I could be wrong.

 

[Calan]

It will be negligable, as the path of least resistance will be the 1/2" line to the catch can.

No... the path of least resistance will be to the slightly lower pressure in the intake snorkel, rather than to the equalized pressure in the catch can.

I wonder how much the unmetered air will affect things

It depends on what you tune with. With DSMLink, I had to pull a crapload of airflow at 50hz, and I never did get LTFT's completely right. It won't affect you at boost, but could cause problems with idle and fuel economy depending on how severe the leak is on your setup.

 

[nicknorth11]

No... the path of least resistance will be to the slightly lower pressure in the intake snorkel, rather than to the equalized pressure in the catch can.

I'll agree to disagree on this one.

It depends on what you tune with. With DSMLink, I had to pull a crapload of airflow at 50hz, and I never did get LTFT's completely right. It won't affect you at boost, but could cause problems with idle and fuel economy depending on how severe the leak is on your setup.

Gotcha. Thanks

 

[Calan]

Why do you disagree? If I'm wrong, please explain.

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[nicknorth11]

Why do you disagree? If I'm wrong, please explain.

I get what you're saying, but I think your diagram is flawed. You have no air leaving the filter, which it obviously will. There will be some pressure in that line, but very little, as the K&N filter is huge and will displace a lot of air. The path of least resistance out of the can isn't going to be the hose that has air coming into it, but the filter.

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[Calan]

Air leaving the VC will try to flow to the lowest pressure point.

The catch can is seeing atmospheric pressure (because of the open filter). At the intake snorkel, pressure will be about .5 to 1 psi below atmospheric pressure (it's been tested... Romeen, Anthony, myself, and several others have been through this many times over the last couple of years). If for some reason your intake snorkel pulls less than this (and is therefore itself close to atmospheric pressure), then yes... you'll flow more air out of the can... which will make having the intake snorkel line useless in the first place.

As mentioned many times, I would either seal the can and use a snorkel off of it to the intake, or vent the can and lose the snorkel altogether.

Either way, it still isn't a great solution for us guys with blow-through GM MAFs....in fact, I have yet to come up with one. There are basically two options:

1. Use both VC ports into a CC to relieve boost blow-by and sacrifice ventilation, or
2. Run the PCV/CC/check valve setup as described in this thread, and deal with the unmetered air

 

[nicknorth11]

Gotcha. I'm still not concerned with the oil too much, but at least now I understand. Thanks.

 

[Calan]

Good luck with it, and good to see someone else is still thinking and trying to come up with a workable solution.

And if you find a better one for us blow-through MAF guys, please let me know

 

[nicknorth11]

I'll be tinkering, but I doubt I'll come up with something smarter people couldn't.

 

[chico904]

After reading every post on this thread, I still have a question. I have seen that while some say to keep some type of element in the catch can, some say to take that elemnt or filter out. I personally want to take it out after seeing the post of it being clogged under 1000 miles so I have no chance of that happening. That being said, I will use the Fram G2 without the filter from the VC to the intake. What should I use between the PCV and the check valve? I saw that poeple say that the Husky seems to leak.

 

[Calan]

The newer Husky bowls definitely have issues. They are polycarbonate and are the natural sworn enemies of almost every fluid and vapor in an engine bay . The problem is that they start to develop cracks, which then causes the drain fittings to leak.

My last catch can incarnation before tearing it all apart for the rebuild was to use two Husky "heads" mounted in a custom fabricated aluminum catch can. It seemed to work ok, except I still had oil in my intake and it was hard to seal the filter heads to my CC due to the top of my CC not being perfectly flat, and the Husky heads not being designed for a flat seal in the first place. (I made some gaskets and sprayed them with copper spray; with a flatter top on the CC, I think they would seal fine)

 

[chico904]

What would you suggest to use instead?

 

[Calan]

No idea man... once things go back together, I'll probably try a different method of mounting the Husky heads on a better CC, just because I like fabricating stuff and I'm cheap

I've heard of people getting good results with an off-the-shelf CC stuffed with steel wool (scotch pads) to help separate the oil.