PCV System Theory of Opertation and the Alternatives. (Updated 4-02-07)

purplehaze · Aug 3, 2007

just bought all the hardware to save my motor, but have to admit, i hate doing my own things.im willing to try this but want to make sure. ryclef,this would be put between the lower intake hose leading to the bottom of the upper intake?and then i can just put i up against the firewall or something?would i see the results right away?

ryclef331 · Aug 3, 2007

purplehaze said:
just bought all the hardware to save my motor, but have to admit, i hate doing my own things. im willing to try this but want to make sure. ryclef,this would be put between the lower intake hose leading to the bottom of the upper intake? YES -Ryand then i can just put i up against the firewall or something? YES -Rywould i see the results right away? You Should! -Ry

purplehaze · Aug 3, 2007

thanks ryclef for the info,going to start on it later today,once the sun settles a bit. let you know on the outcome or any problems i incounter.thanks again.

purplehaze · Aug 5, 2007

Score!!!hooked it all up but on my part didnt see it had a flow direction and had it on backwards but my buddy told me to switch it and within the first 10 minutes of driving i was capturing the oil slowly!thanks alot for the info. :thumb:

ryclef331 · Aug 6, 2007

good deal man.

1BLOWN V8 · Sep 3, 2007

I have a few questions:

I have a 1995 Mustang GT with a ford 302 crate motor with 8K miles on it. I also have AFR165 Heads, TF Stage 1 Cam, RPM 2 intake and rest of the bolt ons. I am getting ready to add a Vortech SQ S-trim with the stock pulley 6-8 PSI. I figured I will be in the mid to high 300rwhp.

Do I need to look into doing something to my PVC system? Will I be fine with my setup since my boost will be only 6-8psi? I would apperciate any advice and also if I would need to make some changes some diagrams would be great.

Thanks

Lane478 · Dec 16, 2007

I had a thought on the subject. I'm wondering if you could hook the air pump to the intake, with a separator in between it and the valve cover, block off the egr, and leave it hooked to the exhaust? It would pull vacuum from the motor without introducing oil mist into the intake. Questions I have are, How much air does the air pump move, would the crankcase fumes harm the cats, and would the pump pull so much vacuum it would create it's own blow by in the cylinders, introducing fuel vapor and other crap into the block? Does the pump need to be left hooked to the mid pipe, or will it make too much noise if left pumping into free air?

94Pro-5.0 · Dec 17, 2007

i recently did this mod and recomend it to anyone. i used the kobalt seporator from lowes.

i have one question. i was at the track a week ago and noticed several 5.0 races cars where they have a braided hose going from the valve cover brether into the headers. they say it eliminates blow-by with no problems. whats your thoughts on this ry?

ryclef331 · Dec 17, 2007

94Pro-5.0 said:
i recently did this mod and recomend it to anyone. i used the kobalt seporator from lowes.

i have one question. i was at the track a week ago and noticed several 5.0 races cars where they have a braided hose going from the valve cover brether into the headers. they say it eliminates blow-by with no problems. whats your thoughts on this ry?

It works...but if you look again, they usually don't run mufflers or have a short exhaust with a straight thru design. Mufflers create backpressure which is exactly what it sounds like...pressure. SO if you have 5psi of backpressure in your exhaust at WOT, you will have 5 psi of crankcase pressure. Thats not much but I feel that in a street car, a BIG crank case vent (i.e. open breathers, catch can, etc.) works just fine. You also have to run "spark arrestors" / check valves on them. IF yo had an exhaust backfire with out them they blow back into the crank case with a possibe fire hazard.

As for the smog pump idea, it might work, but I know for a fact, the cats will NOT like oil mist coming into them AT ALL. You'd clog the cats with the quickness. It has been done but as to how effective it actually was, I can't comment accurately.

Wayne · Feb 28, 2008

i like this thread but I haven't heard anyone mention the oil separator screen under the pvc valve I found that it was stopped up on mine and it was causing the problem of oil getting sucked into my intake through the line that comes from just under the oil fill cap. I had a hard time getting the old screen out because of the gunk built up on the bottom of it. i used a dent puller and gently bumped it out I had to screw it back in three times before I got it out. it was stuck really bad I bought a new screen from the ford dealership part department.

94Pro-5.0 · Feb 29, 2008

i cleaned my screen when i removed my lower intake, and i also replaced the rubber grommet. I have a Home Depot (Husky) Separator on my car right now, i think it looks better than the kobalt from lowes (used to have the kobalt but broke it)

i'll post some pics

ScottyDsntKnow · Apr 16, 2008

Hmmm looks like I'm off to Lowes tomorrow to attempt to find an oil separator. I haven't started my new motor yet and I'd like to keep my worked Cobra intake free of oil sooooo yeah... $15 mod ftw!

ScottyDsntKnow · Apr 20, 2008

Ok, I have an air/oil separator and the hoses and 2 clamps but where should I mount this mofo? THe flat part of my firewall above the brake booster is currently the home of my HI-6 box so I'm not quite sure where to put this beast...

Maybe extend the line all the way out to somewhere on the side like the passenger strut tower and back to the PCV?? Oh and I just found out that there is no screen in the ported exploder intake I put on there. Is that gonna be a problem or not?

thorco3 · Jun 24, 2008

alright guys, got a question for anybody who can help. I've got a 95 and just installed an s-trim. I need some type of vetilation for all the crankcase pressure. Will a catch can actually profide enough so that I will stop blowing out the pcv valve and/or dipstick tube? Or do I need to use breathers as well? I would rather stay away from breathers because I show my car and don't want all the oil mist in the engine bay.

Basically will a catchcan be enough of a vent? guess I should just install one and find out. Actually I don't understand how a catch can will vent crank case pressure as opposed to a breather stuck in your valve cover...

Paul · Jun 24, 2008

Thorco, you could start with perhaps running your PCV through a check valve to a catch can.

I use this one:

http://www.accmachtech.com/catchcans.asp

You can also have bungs welded to your valve covers that run into a vapor canister. I run that as well. You don't have to worry about oil getting all over your valve covers that way.

Paul.

thorco3 · Jun 24, 2008

Paul said:
Thorco, you could start with perhaps running your PCV through a check valve to a catch can.

I use this one:

http://www.accmachtech.com/catchcans.asp

You can also have bungs welded to your valve covers that run into a vapor canister. I run that as well. You don't have to worry about oil getting all over your valve covers that way.

Paul.

the check valve would need to go between the pcv and catch can correct? where did you order that catch can from? I know I've seen pics of your motors before but if you've got a picture handy would you mind posting it up or pm'ing me.

I'm thinking of putting a push in breather in the top of my oil fill tube and hooking up a catch can for the time being.

or should I just delete the pcv all together and run breathers to vent the pressure...?

Paul · Jun 24, 2008

Yes, you're correct on check valve placement.

I ordered mine directly from them a few years ago - the website now has contact numbers for some other distributors.

I'd advise against the push-in breather unless you do the tuna-can mod to capture the oil vapor. It will make a mess.

PCV Catch Can:

Vapor Can - one -12AN line coming from each valve cover is attached:

Paul.

thorco3 · Jun 24, 2008

something else I just thought of... how does the smog pump affect all of this. I deleted the smog stuff and capped off the back of the heads long before the vortech install. could that be creating even more crankcase press.?

and what is the tuna can mod... guess that is something like putting a small bowl/tuna can under/around the breather to catch any oil residue...?

why would you need a check valve between the pcv and catch can?

str8stang036 · Jul 10, 2008

Reading this makes me more confused about my current setup. I have a PCV, but its plugged up. I am using the same port in the intake for the brake booster and other vacuums. I am using to open breathers, one on each cover. I have a twin turbo setup with a blow-thru maf. Do I have a vacuum leak? Some say yes, some say no.

ryclef331 · Jul 22, 2008

str8stang036 said:
Reading this makes me more confused about my current setup. I have a PCV, but its plugged up. I am using the same port in the intake for the brake booster and other vacuums. I am using to open breathers, one on each cover. I have a twin turbo setup with a blow-thru maf. Do I have a vacuum leak? Some say yes, some say no.

Does anything off the valve covers go to the intake? AND (What is the overlooked part) do you still have a PCV Valve in the back of the lower intake and if yes, is that hooked to the upper intake? If you answered no to both of these, then no you don't