HOW TO: *Properly* disconnect your PCV ...

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orion
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HOW TO: *Properly* disconnect your PCV ...

Post by orion »

So, I see KA-T people having boost leaks from the PCV valve rubber lines all the time.

Hell, I see KA-T guys with the PCV connected. Why?

Vent it to the atmosphere.

And the proper way is NOT to just remove the 4-into-one deal, and cap each bung with a vacuum cap. They will leak. They crack, then leak. They pop off.

And removing the line from the valve to the inlet of the 4-into-1 deal, then capping that one inlet...is also a half-ass way to do it. It will leak, sooner or later.

I have tried pretty much everything to cap these...and what I've been running for the last few years is the bungs, folded over, and clamped close. They are air tight...but they come out pretty easy if you tug. So it's always worried me.

SO, to that end...here's the proper way to remove the bungs, and close the holes for good...without a welder. Just tap them for 3/8-16, and cap the holes with threaded plugs (with allen key heads).

I leave the PCV line coming directly off the valve connected...and just turn it 90-degrees...so it vents down onto the motor mount bracket if anything comes out of it..

...................................

1) Remove the upper half of your intake manifold.

2) Locate the PCV 'manifold' that you need to remove:

Image

3) Remove the vac lines and the metal hard lines.

4) Then remove the bungs with a pair of vise grips...wiggle a little back and forth, and they will come right our.

*****

This leaves you with 4 holes that are 5/16" I.D. A 3/8-16 tap requires a 5/16" ID hole to tap...so this work out perfect.
1/8" NPT works as well...so does 9x1.25 metric. But it's harder to find taps...and 9x1.25 plugs are impossible to find. 1/8" NPT plugs can be bought at Home Depot or Lowes...they are brass, for plumbing.

*****

5) To cap them, buy these:

Image

6) Then tap them:

Image

...

7) Then, put a little RTV (I like 'Ultra Black'...) on each plug, and thread them in:

Image

...

You're DONE.

Hope that helps someone...and I know for some of you old-schoolers, this is nothing new...but maybe not?

- Brian
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Post by Kim_jong_il »

That's what I ended up doing on mine after having it ultra-sonically cleaned and bead blasted. Used 1/8 NPT plugs and teflon tape. By far easiest way to go and cleans up the under manifold area. The only thing left down there is the harness and idle control valve.
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Post by pr240sx »

A NOS nozzle there will rock!!

But will suck when changing jets!!

Now, blocking these ports, should idle vaccum somewhat rise?
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Post by 8-bit »

I basically took off all the rubber and there was a nearly 1 inch nipple on each hole. I put a lot of JB weld in em. I really pray (to the dirt) that they will hold up. So far 12psi for several months, and 30psi on occasion when I have pressure checked my system.

EDIT: make sure you do the RTV if you're gonna do this guys! Air loves to leak around those threads!
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Post by Lance »

Nice write-up Orion, I'll probably be doing this when I take off my IM in the near future.

I see you just flattened and folded over that coolant line. How is that working for you? I ask because this is where my problems are coming from. I have JB weld + high temp RTV + Caps and they keep leaking.
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Post by DrEaMeR_VaNg »

Well, I have my intake manifold off my car because I'm doing a build and I was looking thru the "How to remove emission" page a while back. When I was looking thru it, it seem like a hard job to do and I think ispypsi said it will throw codes so I thought I wouldn't bother to do anything to my intake manifold. What do you guys think? Should I or should I not?

Anywho, are there any advantages of doing this? Does it differ from a 97' intake manifold vs a 93'? Will it throw any codes?

Let me know. THANKS! :D
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Post by N240sxvayne »

...sorry to get off subject but is there a quick and easy way of replacing the pcv (engine in car) without removing the intake manifold...???
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Post by orion »

^^^ Quick and easy...NO.

But it can be done.

It's just TIGHT back there. Remove the oil filter and that will help a ton.

...

Glad some of you find this useful.

- Brian
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Post by N240sxvayne »

is it better to get it from the top or the bottom of the car? the pcv
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Post by LigouriRd. »

It is funny that you posted this; I just had one of my vacuum plugs pop off this weekend while on a time attack run. You are correct about the rubber plugs, with the exception of the one that popped off, all the others are cracked. Unfortunately I cannot pull out and tap the intake manifold with it on the car.

As a temporary or hopefully semi-permanent solution I have ordered some Silicone caps and I plan to tie wrap them in place for extra security. Silicone shouldn't dry out and crack and hopefully the wall thickness is such that they won't balloon up on me.
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Post by smracing »

That is what I do for all the ka's I build. I recommend using 1/8 npt instead of straight thread plugs. The holes don't work well for nitrous because a nozzle is 1/16npt, and the hole is bigger than that. You can weld in bungs though. Here is my manifold tapped for 2 stages of nitrous

Image
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Post by nissanfanatic »

While I had my car apart, I did do something about it. Although, as you can imagine, I used my favorite, JB weld..
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Post by pr240sx »

Sweet dry sump!!!

Care to elaborate on your oiling system?
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Post by klattr1 »

I did the same on my stock intake manifold a while back (tapped out the ports to 1/8" NPT and put plugs in).

good info Orion!
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Post by Ihiryu »

Damn, I wish I had thought about this a few months back when i did my emissions removal. Oh well I guess when i go do my timing chain service then I'll go back and do this. Nice write up Orion
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Post by 1wheelwonder »

I welded my holes up.
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Post by seanc »

what did you guys all do about the other side of the line that actually hooks up to the pcv valve? where did you route the pcv valve line?
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Post by xtearsfallforeverx »

that end should go into a catch can along with the line from the vc and then back into the intake before the turbo, i would think.
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Post by lov2xlr8 »

im thinking of taking my manifold apart this weekend since my car is not running to do the emmissions and butterfly removal and it'll be a good time to do this, would it matter if im not turbo yet? i wouldnt like to take that thing apart again in a couple of months....
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Post by orion »

^^^ Turbo or not..you can 'dump' the PCV.

Just take the line coming off the valve, and turn it 90-degrees...so the outlet points down to the motor mount.

Remove the rest.

- Brian
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Post by ZiG »

Wait, so after this you won't have the crankcase under vacuum at idle? I dont know if I like that idea much...

Did you at least run the valvecover breather line to the pre turbo intake?
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Post by Ichi-Go »

If I drop my mani off at your house with a 12 pack of miller lite will it be done by labor day? Just kidding.

THREADJACK alert.

Dry sump KA. That is all.
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Post by 8-bit »

xtearsfallforeverx wrote:that end should go into a catch can along with the line from the vc and then back into the intake before the turbo, i would think.
Dude.. about the VC line. I had mine set up like you described a while ago, but I changed to a breather filter on the VC. On every single diagram I have seen, it shows fresh air GOING IN the VC and then oily air coming out of the PCV. That means the PCV needs vacuum as we all should have it hooked up, but the VC should not have a vacuum. On our N/A intake tubing the VC has a hose that goes to it, but there is some metal thing in line that I recall to be a check valve. I am not 100% sure though because the last time I saw one was about 9 months ago.
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Post by xtearsfallforeverx »

well im pretty sure that the hose on the valve cover receives vaccum as well, but I may be wrong. if thats not the case, then just put a breather on it like you said and just run the pvc to a catch can, then route back before the turbo, after the mafs.
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Post by lov2xlr8 »

This leaves you with 4 holes that are 5/16" I.D. A 3/8-16 tap requires a 5/16" ID hole to tap...so this work out perfect.
1/8" NPT works as well...so does 9x1.25 metric. But it's harder to find taps...and 9x1.25 plugs are impossible to find. 1/8" NPT plugs can be bought at Home Depot or Lowes...they are brass, for plumbing.
im picking up the stuff i need to do this and theres something i don't understand....
to use a 1/8npt plug do i have to find a 1/8NPT tap, or you are saying the 1/8NPT plug works on a 3/8-16 thread?....
cause i found the 3/8-16 tap but i can't find the f-ing plugs.... i'll try another place later today...
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Post by orion »

3/8-16 tap, you need 3/8-16 plugs.

1/8 NPT tap, you need 1/8 NPT plugs.

3/8-24 tap, you need 3/8-24 plugs...

9x1.25 metric tap, you need 9x1.25 plugs (impossible to find).

...

Basically, once you remove the bungs...you have a perfect 5/16" ID hole to tap...the taps listed above are all within 1/64" of a perfect fit for a 5/16" pilot hole.

- Brian
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Post by ghostchild316 »

I did this about 3 yrs ago.I filled the holes with JB-Weld.Holds fine and still doesn't leak to this very day.
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Post by Kim_jong_il »

For the person asking about the small coolant hose line that tee's out to the manifold. Instead of crushing it and folding over just cut that whole protusion off and grind it down so there are no burs. You can just slip the OE water hose further back to cover up the small exposed hole and tighten the clamp fairly stout and you're set.
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Post by xtearsfallforeverx »

you could be even more ghetto and jb weld a piece of tin around the outlet. ha.
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Post by viperbite »

not to bash yall for doing this.
but theres a reason its there...
it helps equalize the pressure between all 4 runners

the longer the runners the less likely the pressure will be exactly the same
so that valve helps there.

i wouldnt remove it if i did a setup personally...

it "cleans it up" thats it...
if stacking dominoes as a head gasket helped out for performance id do it lol but it doesnt
and taking a pcv valve off doesnt help performance it just cleans itup.... not worth it ot me

good writeup though
and glad you atleast did it correclty
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