Eliminating the PCV system (long)

[Steel Hawk]

This may be a newbie question...

I've done some research, but still can't find the answer. Assuming the following is correct:

The PCV valve is a one way valve that takes excess blow by from the head and sends the air / oil vapors into the intake -> ic piping -> intercooler. In the intercooler the oil vapors cool down and it results from oily film to small amounts of oil. The oily air reduces the octane rating, thus reducing performance and causing a greater chance for detionation. (Although it's an extremely small reduction).

There's talk of catch cans, leaving it alone, etc.

Now heres my question. Assuming you just left the PCV valve on (by itself it doesn't do anything except let air out) and attached it to a hose running to the ground (and plugged the intake manifold), what would happen? I assume there wouldn't be any performance problems, and a few drops of oil would come out and stain your drive way, but would it be bad?

I mean would oil run out of the car all day and leave huge stains over the road? Just curious.

edit:
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also, would I loose performance due to vaccume pressure?
----------------------
Thanks.

 

[waterdeep]

I have been doing this on my dsm since I bought it. As for the oil spots I notice nothing on my drivway period. I think that when any oil comes out it must be hen driving, and if it accumulates and runs down while ti parked it hasn't yet leaked on me. I cleaned out my intake manifold very good before doing this as well as removing the EGR as well. I have since taken out my manifold and ic pipes since then and they remain nice and clean =)

 

[EROK81]

Exactly. I hollowed out my PCV valve and plugged the hole on the intake manifold. I also ran a hose off of the breather, zip tied the two together and run them down so they just hang there. No oil spots anywhere.



Of course that info is all not true due to it being illegal, and we don't do that kind of stuff because it is bad for the environment.

 

[waterdeep]

 

[racer]

Ok I did the same thing as u guys and after the first run I got oil liking out of my oil cap?I have never had oil leaking out trough my oil cap.But now right after I did this i got leak.What is going on.Is it true that if we do that the oil presure is going to rise up and can cause leaks from valve cover gasket hoses and oil cap?

 

[Mike 99GSX]

Dude
How many topics do you need to post this in. You ressurect a 12 month old post when you said the same exact thing in a post 1 up from this

 

[racer]

so more ppl can see it,simple as that.If u not gona help me plz

 

[RiceKiller_TSi]

Originally posted by Steel Hawk
This may be a newbie question...

I've done some research, but still can't find the answer. Assuming the following is correct:

The PCV valve is a one way valve that takes excess blow by from the head and sends the air / oil vapors into the intake -> ic piping -> intercooler. In the intercooler the oil vapors cool down and it results from oily film to small amounts of oil. The oily air reduces the octane rating, thus reducing performance and causing a greater chance for detionation. (Although it's an extremely small reduction).

There's talk of catch cans, leaving it alone, etc.

Now heres my question. Assuming you just left the PCV valve on (by itself it doesn't do anything except let air out) and attached it to a hose running to the ground (and plugged the intake manifold), what would happen? I assume there wouldn't be any performance problems, and a few drops of oil would come out and stain your drive way, but would it be bad?

I mean would oil run out of the car all day and leave huge stains over the road? Just curious.

edit:
----------------------
also, would I loose performance due to vaccume pressure?
----------------------
Thanks.

As for the stains, I dont take any chances making my nice clean driveway look like raisin toast so I made my own catchcan.
http://www.geocities.com/misterdeedub75/catchcan.html
I havent had any problems with a new oil leaks being generated by doing this. I've replaced every oil gasket on my car from necessity due to one fixed causing another problem. (example)
1. Replaced dipstick that used to pop out and spray oil under boost.
2. Caused oil cap to leak. Replaced cap and doubled up on gaskets.
3. Crank angle sensor springs leak. Replaced O-ring seal there.
4. Valve cover takes a leak. Replaced valve cover.
I agree that you should "definitely" remove EGR crap, clean the intercooler, and intake. Once this is done your intake will stay cleaner, and intake air slightly cooler. I felts gains once completing these things.

 

[DSM90AWD]

The more your rings are worn the more blowby / oil vapors produced in the crankcase = more oil vapors vented from the PCV / breather system.

If you just plug the PCV all you have left is the breather. If that too is restricted then where else will the vapors go?

I took the spring out of the nipple side of the PCV valve.. effectively blocking it open.. and rau to my new catchcan made of PVC ala Home Depot to match my intake pipe

 

[RipperXX]

Well I did something similer which I think works better.


I just cut the hose going from the PCV valve to the intake and sliped in a clear plastic fram fuel filter I saw at wally world for $2...

works perfect, catch can and filter all in one. And since it's clear, I can see when to change it.





(if you pay $40 for a breather/catchcan.... you got riped big time)

 

[DSM90AWD]

Originally posted by RipperXX
Well I did something similer which I think works better.


I just cut the hose going from the PCV valve to the intake and sliped in a clear plastic fram fuel filter I saw at wally world for $2...

works perfect, catch can and filter all in one. And since it's clear, I can see when to change it.

Nice job! Where exactly did you cut the PCV? Does it still thread in?

(if you pay $40 for a breather/catchcan.... you got riped big time

Damn strait
though I hear those GREEDY *bling* catch cans add something like 20HP

 

[johnh]

Originally posted by RipperXX


I just cut the hose going from the PCV valve to the intake

 

[racer]

May be he doesnt know what exactly is PCV valve or maybe he ment to say intake manifold,who knows .Anyways can someone help me plz I stil dont have answer?
Idid catch can and after test drive I got oil liking out of my oil cap?I have never had oil leaking out trough my oil cap.But now right after I did this i got leak.What is going on.Is it true that if we do that the oil presure is going to rise up and can cause leaks from valve cover gasket hoses and oil cap?Thanks in advance.

 

[Defiant]

Originally posted by racer
May be he doesnt know what exactly is PCV valve or maybe he ment to say intake manifold,who knows .Anyways can someone help me plz I stil dont have answer?
Idid catch can and after test drive I got oil liking out of my oil cap?

Replace the oil cap gasket.

 

[Defiant]

Originally posted by Steel Hawk
This may be a newbie question...

I've done some research, but still can't find the answer. Assuming the following is correct:

The PCV valve is a one way valve that takes excess blow by from the head and sends the air / oil vapors into the intake -> ic piping -> intercooler.

No. The PCV valve goes straight into the intake manifold. The one going into the IC etc can be fixed thus:

http://www.tgilmore.com/talon/catchcan.html

You're not getting enough fumes from the PCV to affect performance (unless the engine's about dead anyway), and it's only open under vacuum.

http://www.hastingsfilter.com/engineering/tsb_94-2r.html

 

[racer]

Ok Defiant i did read this http://www.hastingsfilter.com/engineering/tsb_94-2r.html and from what I understood is that,it is nessesery to have a PCV valve since it mesure the gases that are going into the manifold and if it is not there,it ll make the engine parts rusty and the oil heavy.So when we do 'catch can' and eliminate the PCV valve aren't we going to #### up the engine,since there will be no mesurment and noting to take those gases out?Also arent we gona lose that extra air that comes from the PCV valve if we eliminate it?Im afraid that my engine is not geting enough ventilaton with that catch can.

 

[DSM90AWD]

If you are not just "plugging" the PCV system up then the blowby gasses will still be vacated via the (+) pressure in the crankcase to the catch can (as long as it is vented to release pressure).

The PCV system when hooked up to your intake is an enviro-friendly way to collect these gasses.. that's all. In a turbo charged application it's more meaningful to do this mod as the oil residue can funk up the IC, intake, cause carbon deposits on the intake/pistons..etc. causing poor performance.

Another nice link is from Taboo

Regardless.. if you change your oil/filter at recommended intervals will not have problems with oil contamination.

Originally posted by racer
Ok Defiant i did read this http://www.hastingsfilter.com/engineering/tsb_94-2r.html and from what I understood is that,it is nessesery to have a PCV valve since it mesure the gases that are going into the manifold and if it is not there,it ll make the engine parts rusty and the oil heavy.So when we do 'catch can' and eliminate the PCV valve aren't we going to #### up the engine,since there will be no mesurment and noting to take those gases out?Also arent we gona lose that extra air that comes from the PCV valve if we eliminate it?Im afraid that my engine is not geting enough ventilaton with that catch can.

 

[racer]

Ok then what about that extra air that the sistem used to suck from the PCV valve? isnt removing the PCV valve going to cost a bit less air wich means less power?

 

[DSM90AWD]

Your sucking in oil vapors and blowby via the PCV not air.

IMO since you have an N/T.. I would'nt bother bypassing the PCV as there's little for you to gain. Unless your PCV system is not working.

Originally posted by racer
Ok then what about that extra air that the sistem used to suck from the PCV valve? isnt removing the PCV valve going to cost a bit less air wich means less power?

 

[RiceKiller_TSi]

I was just curious as to "how" one would go about "hollowing out" a PCV valve to be rid of that valve inside.... I cant find a link to that anywhere. If I could do this I could eliminate the possibility of that thing sticking.

 

[Mike 99GSX]

Originally posted by RiceKiller_TSi
I was just curious as to "how" one would go about "hollowing out" a PCV valve to be rid of that valve inside.... I cant find a link to that anywhere. If I could do this I could eliminate the possibility of that thing sticking.

An easier thing to do is to replace it with a 1/8 NPT to barb adapter fitting. The PCV threads aren't NPT but you can chase the hole with a tap and then you're good to go. Just be careful with shavings if you don't take the valve cover off

 

[elementalwindx]

Originally posted by Mike 99GSX
An easier thing to do is to replace it with a 1/8 NPT to barb adapter fitting. The PCV threads aren't NPT but you can chase the hole with a tap and then you're good to go. Just be careful with shavings if you don't take the valve cover off

is there anything to fit in place of the PCV valve that will fit the same size. in case it doesnt work (or i have to get inspected) and I want to put the PCV valve back in its origional place?

 

[Mike 99GSX]

The threads are 1/8" BSP standard I think. They are very close to 1/8 NPT in size and pitch but not the same. You could probably find a replacement PCV valve at an autoparts store that is 1/8 NPT instead.

 

[RiceKiller_TSi]

Originally posted by Mike 99GSX
An easier thing to do is to replace it with a 1/8 NPT to barb adapter fitting. The PCV threads aren't NPT but you can chase the hole with a tap and then you're good to go. Just be careful with shavings if you don't take the valve cover off

I'm not familiar with the term "NPT"... I DO know how to chase holes but I dont think you mean what I think. Do you know of a VFAQ on this anywhere? Also like ol boy said is this reversible? Or permanent change of the valve cover PCV valve threads?

 

[Mike 99GSX]

Originally posted by RiceKiller_TSi
I'm not familiar with the term "NPT"... I DO know how to chase holes but I dont think you mean what I think. Do you know of a VFAQ on this anywhere? Also like ol boy said is this reversible? Or permanent change of the valve cover PCV valve threads?

NPT stands for national pipe thread. 1/8 NPT is slightly larger than the threads that are in there right now. What I am suggesting is: go to a harware store and buy a 1/8" NPT tap because aftermarket straight fittings are going to be in this size and pitch because it is a standard. ( You will never find a straight fitting that is the same thread as what the Mitsu PCV valve is). Make your new hole and get a straight fitting. Then go to a Napa or Autozone and get a PCV valve that is 1/8" NPT to match your new hole instead of the Mitsu one. That way you can swap it back in if you have to. I hope this clears it up.