PCV Deletes, Catch Cans, and You

[iRoush]

Okay so I'm stumped on Catch can setups and how they are meant to be run. I'm getting conflicting information about how my car is letting in unmetered air, or that the setup is actually correct.

Currently I'm running the Catch can only to the driver side. It's a vented moroso, and it blows out a decent amount of smoke but no oil is collecting in the can. I'm running an old school breather on the passenger side and both the plenum and jlt are plugged off. My question is, how the hell am I supposed to route this thing? Do I need another bung welded to the catch can or?

[ttocs]

I have always wondered when/why we need one?

[iRoush]

I have always wondered when/why we need one?

i use it to keep the blow by from getting into the intake. my last engine was gummed up from all of the oil

on the intake. This keeps the oil from recirculating through the engine keeping the engine clean. it's "working" right now by keeping oil from recirculating but I dont know if it's causing a vacuum leak by doing so. this combined with e85 makes my oil come out as clean as it did when I put it in

[Det_Riot]

I have literally always wondered this exact same thing! :stumped:

[Alscobra]

The pcv valve is there for emissions control. Just routes crankcase gasses back into the intake to be burned. All crankcases will build pressure. Some valve covers have baffles to keep oil from being blown out with the gasses. You can run the catch can anyway you want or no can at all. Just might get a little smoke.

[95opal]

Okay so I'm stumped on Catch can setups and how they are meant to be run. I'm getting conflicting information about how my car is letting in unmetered air, or that the setup is actually correct.

Currently I'm running the Catch can only to the driver side. It's a vented moroso, and it blows out a decent amount of smoke but no oil is collecting in the can. I'm running an old school breather on the passenger side and both the plenum and jlt are plugged off. My question is, how the hell am I supposed to route this thing? Do I need another bung welded to the catch can or?

Your current set up is fine aside from the the oil mist from the passenger breather blowing around the bay. Funtionally its fine since you pluged the pcv in the intake.

For a cleaner non oil misted bay your last drawing woul be the way to go but like I said your current set up is fine.

[Alscobra]

If you plug the PVC ports off, the crankcase will build pressure and it may create oil leaks if it doesn't vent.

[iRoush]

Your current set up is fine aside from the the oil mist from the passenger breather blowing around the bay. Funtionally its fine since you pluged the pcv in the intake.

For a cleaner non oil misted bay your last drawing woul be the way to go but like I said your current set up is fine.

looking at it i just don't see how it works. there's no suction/pressure at the canister picking up the oil, hence why the canister is empty. even if I attached the passenger side there's still no pressure in the system to pump it to the canister since I have a filter on the canister. Would I have to cap it off and run two seperate lines to to the canister? or would that keep too much pressure in the system and the filter is the release of that pressure?

[iRoush]

doesn't the system also require the vacuum from the intake as well to function?

[Alscobra]

doesn't the system also require the vacuum from the intake as well to function?

That's just to burn crankcase gasses. If you have a that filter thing on the opposite valve cover like many people have, you're creating a vacuum leak through your crankcase. = extra air through your intake that the MAF doesn't read. Can run your engine lean. The crankcase should be a sealed system for the pcv to operate correctly.

[iRoush]

That's just to burn crankcase gasses. If you have a that filter thing on the opposite valve cover like many people have, you're creating a vacuum leak through your crankcase. = extra air through your intake that the MAF doesn't read. Can run your engine lean. The crankcase should be a sealed system for the pcv to operate correctly.

so I need to run the system like the 3rd or 4th diagram? either T it off by the passenger side or T it into two fittings into the canister?

[Alscobra]

Yeah that should work. Just plug the pcv line off so no vacuum leak. Both valve covers are connected through the heads and crankcase oil ports. So you really only need to run it from one valve cover and seal the holes in the other. The vapor space is all connected either side.

[Det_Riot]

So basically in my method, the drivers side vent creates a vacuum leak. And ideally you should have both valve covers contributing to the catch can

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[revhead347]

Ok, there's a lot of information that is leading away from the most important discussion. The purpose of the PCV system is to keep combustion gasses from dirtying up your oil. If you have a forced induction system then removing the PCV system keeps boost from blowing your gaskets out. If you don't have forced induction, there is no incentive to remove the PCV system. If you are worried about stray oil being sucked up into the intake, then it's better to install an oil seperator between the PCV valve, and the intake. If you do decide to remove the PCV system, then change your oil more often.

Kurt

[Alscobra]

So basically in my method, the drivers side vent creates a vacuum leak. And ideally you should have both valve covers contributing to the catch can

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It doesn't make a difference one side or both. Remember the oil reaches the top of the heads then runs back down through oil passages to the crankcase by just gravity. The crankcase equals out both sides. It's all connected so only one side will be sufficient and just cap the other valve cover.

[Alscobra]

Ok, there's a lot of information that is leading away from the most important discussion. The purpose of the PCV system is to keep combustion gasses from dirtying up your oil. If you have a forced induction system then removing the PCV system keeps boost from blowing your gaskets out. If you don't have forced induction, there is no incentive to remove the PCV system. If you are worried about stray oil being sucked up into the intake, then it's better to install an oil seperator between the PCV valve, and the intake. If you do decide to remove the PCV system, then change your oil more often.

Kurt

It's not to prevent dirtying oil. It's to burn those gasses instead of polluting the air we breathe. The first form of emissions control. If it was about dirty oil, they would just vent the gasses. Boosted motors actually create intake pressure so the vacuum is gone. The pcv is also a check valve that won't allow pressure back in to the valve cover.

Edited July 26, 2012 by Alscobra

[iRoush]

Yeah that should work. Just plug the pcv line off so no vacuum leak. Both valve covers are connected through the heads and crankcase oil ports. So you really only need to run it from one valve cover and seal the holes in the other. The vapor space is all connected either side.

PCV lines are plugged on the intake and plenum. Next question, what size fitting will work on the passenger side valve cover? it's gotta go into that PCV grommet and I'm thinking my safest bet is getting a barbed t fitting, just don't know the size I'll need.

[revhead347]

Google is your friend.

http://autos.yahoo.com/maintain/repairqa/engine/ques079_1.html

Kurt

[Alscobra]

PCV lines are plugged on the intake and plenum. Next question, what size fitting will work on the passenger side valve cover? it's gotta go into that PCV grommet and I'm thinking my safest bet is getting a barbed t fitting, just don't know the size I'll need.

Most pcv valves are all the same size. Here's a secret. The pcv valve for about an 01 Chevy truck isn't actually a valve. It's a housing with a small hole in it (just an orifice hole). I would buy one of those but drill the hole a bit larger.Maybe 3/16 or 1/4 That should be the easiest way.

[Alscobra]

Google is your friend.

http://autos.yahoo.com/maintain/repairqa/engine/ques079_1.html

Kurt

http://en.m.wikipedia.org/wiki/Crankcase_ventilation_system#section_5

Read up. Venting the gasses to the atmosphere will do just as good to prevent contamination.

[Det_Riot]

Ok, there's a lot of information that is leading away from the most important discussion. The purpose of the PCV system is to keep combustion gasses from dirtying up your oil. If you have a forced induction system then removing the PCV system keeps boost from blowing your gaskets out. If you don't have forced induction, there is no incentive to remove the PCV system. If you are worried about stray oil being sucked up into the intake, then it's better to install an oil seperator between the PCV valve, and the intake. If you do decide to remove the PCV system, then change your oil more often.

Kurt

If this is true, won't you run into the issue of excessive crankcase pressure? When I only had the pcv valve routed to the intake and solid valve covers, I would spit oil out of my dipstick tube at the track.

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[Alscobra]

If this is true, won't you run into the issue of excessive crankcase pressure? When I only had the pcv valve routed to the intake and solid valve covers, I would spit oil out of my dipstick tube at the track.

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You either had a bad pcv valve which is a backflow preventer(check valve) or some compression blow through into the crankcase.

[revhead347]

The point is, a certain amount will vent on it's own from pressure, but positive flow brings in clean air. Without positive flow to bring in fresh air, the combustion gasses just sit in the crankcase and do their thing. That's why the system is designed the way it is. If venting gasses did the same thing, the manufacturer would simply vent the crankcase to the intake without putting in a breather element on the other side.

Kurt

[Alscobra]

The point is, a certain amount will vent on it's own from pressure, but positive flow brings in clean air. Without positive flow to bring in fresh air, the combustion gasses just sit in the crankcase and do their thing. That's why the system is designed the way it is. If venting gasses did the same thing, the manufacturer would simply vent the crankcase to the intake without putting in a breather element on the other side.

Kurt

It's just to sweep the gasses. Some manufacturers don't vent the opposite side. The reason they return them to the intake is because the gasses are hydrocarbons. Pollutants.

[iRoush]

Figured out the size is 3/4" for the pcv grommet.

You guys think this will work to plug it? Because I can't find a 5/8" x 3/4" x 5/8" Tee Fitting anywhere.

[SniveTroll]

you dont listen to me. i told you the cleanest way to do it. its not easiest but definitely the cleanest and efficient.

[SniveTroll]

on the 4.6 SOHC.

from local parts store^^^.

6ft. 1/2 hose maybe

1 1/2" 90* elbow

1 new rubber grommet.

1 1/2" plastic Tee.

tig a catch can equivalent. or alter a moroso catch can.

Edited July 27, 2012 by SniveTroll

[SniveTroll]

Vacuum from the CAI pulls the air out of the crankcase. thus why you end up with oil in the intake track. i do agree that it should be a closed loop system. Ford engineered it that way. for several reasons.

*piston ring pressure.(think about old school bicycle pump that the rod comes out the tubes too often. it doesnt produce air enough)

*emission controls. (Hi California and tree hugging hippies)

*closed loop for Oil decontamination(think of tupperware and how food stays fresh)

*PCV valve is just a one way check valve. it prevents backflow.

opening the PCV system wont necessarily give a lean condition if unplugged. it simply builds up stagnant oily gases. it doesnt suck in air. it does push air. remember theres a rotating assembly moving hundreds/thousands of RPMS. thats the after affects of the engine already pumping the air. the engine lean condition is from not closing the vacuum ports on the intake. if you have excessive worn rings and a BLOW by situation then the PCV begins to blow air and causing lean/rich conditions.

personal note: ive done some boneheaded junk with the STOCK 4.6 engine in my rig when i first bought it. in my trade i play with forced air and have fun breaking stuff.

[iRoush]

you dont listen to me. i told you the cleanest way to do it. its not easiest but definitely the cleanest and efficient.

I listen, I'm just not going with your idea. Although its a good one, it's not worth the extra effort in this case. I'm

just going to plug the passenger cover and call it good for $2 vs all the lines and labor for your way.

[SniveTroll]

The valve covers are the ceiling of the crankcase. Letting 1 side breathe efficiently vise both MAY have build up on one side. Your said way would work but inefficiently evacuating the gases. Remember the chains pull fluid to the heads. More in depth thinking there.

Sent by smoke signals

[95opal]

Some good and some really bad info here. If youve plugged the PVC and also the port on your CAI, then simply connect the one cover you have venting from the old school breather to the catch can and your done. Or leave it venting through the old school breather. Dont cap that breather off...both covers need to vent. People are over complicating a very simple set up.

[ttocs]

never been more confused on this....

[SniveTroll]

I do tend to nerd things up.

Sent by smoke signals

[Forcefedhatch]

Mine have twin baffled old schools, never had a problem..

Sent from my iPhone

[revhead347]

PCV setups precede EPA emission and California emissions. They vent into the intake so the car doesn't look retarded with smoke coming out of the hood.

Kurt

[Forcefedhatch]

My pcv setup..

Two on each side lol.. No smoke.. Unless under lotsa boost lol..

Sent from my iPhone

[SniveTroll]

N/a i used the breather on the passenger side and normal PCV on the drivers'. i didnt like it one bit. i always smelled oil.

[Paul]

On the Unicorn, I ran a catch can inline between the vacuum source (brake booster) and the PCV on the back of the intake. It was filtered and baffled.

I also ran two -12AN breather lines from the valve covers to a breather canister that was vented to the atmosphere.

The Unicorn always seemed to have high crankcase pressure, (not sure why, perhaps very high piston speed?) and this seemed to do the trick, while keeping any oil vapor off the motor and away from the inlet tract.

Paul.