Getting rid of the PCV line?

[Number21]

My truck has this hose from the valve cover to the carb, the PCV I think? I'm trying to clean up my engine and I want to get rid of that hose. Can I put a breather cap on that valve cover, or do I need to get new ones with different holes? I have a breather on the other side, I see a lot of engines with one on each side....

[INSIDIOUS '86]

Keep it. Helps evac gasses inside crankcase and prevents high pressure buildup
Posted via Mobile Device

[Zane M]

Keep it. It does far more good than harm.

And for the sake of conversation, if you were to replace it with a breather, you really wouldn't be cleaning up the engine compartment as you will end up with oily residue on your valve covers.

[Corts60]

I agree with both above. Keep it. Keeping a vacuum in the crankcase is a good thing.

[Number21]

Hmmm...I guess I could get a stainless line or something. I'm thinking about getting new valve covers though, would covers like this have the correct hole for the PCV line?

http://www.ebay.com/itm/350555609822

Looks like holes for two breathers to me.

[butch86]

you put a bung in the hole and install a pc valve in it and run your hose.

[wilkin250r]

You want to have your PCV connected to manifold vacuum, but you might have some options. I have seen some engines that use a short hose routed to a vacuum port BEHIND the carburetor rather than in front of it. I've even seen some that don't even come off the top of the valve cover at all, but instead come from the very back, right next to the firewall, so at first glance it looks like there is no PCV at all. It really makes for a nice, clean setup. Add some good wire looms to organize the spark plug wires and you got a nice looking engine compartment.

A quick google search for PCV valves will give you good information on WHY you need that guy connected to manifold vacuum.

[frog210]

Mine goes to my air filter?
is that wrong?

[INSIDIOUS '86]

Originally Posted by frog210

Mine goes to my air filter?
is that wrong?

I belive earlier cars did this too. But they were simply trying to keep crankcase gases venting to the atmosphere to keep the self righteous EPA happy
Posted via Mobile Device

[frog210]

But it looks like a previous owner did it
cus my elderbrock air breather looks pretty new
It looks like the po did it it looks like it was drilled
should i move it to the carb?

[Firebirdjones]

Number21,,,,,First,,,,I'd flip the valve covers from side to side. PCV should be in the front driver side valve cover,,,not the rear passenger side.

PCV's are more effective at removing crank case pressures from the driver side due to the counter clockwise rotation of the crank shaft.

That's one reason why your PCV is soaked with oil back there. As you accelerate, any oil in the cylinder heads runs to the back, and is then sucked up through the PCV, which is coating the inside of the intake manifold, backs of the intake valves and the tops of your pistons,,,,Eeeeewwww
You may find that flipping the covers and putting the PCV where it's supposed to be will cut down on your oil consumption too,,,just a heads up


Frog,,,,,On the PCV going to the air filter,,,,that's incorrect. That hose going to the air filter is supposed to be your fresh air for the crank case,,hence the reason it's in the air filter with a small filter inside the air cleaner housing attached to the hose. This setup goes directly into a baffled hole in the valve cover (no PCV valve). this setup should be on the passenger side.
The PCV should be on the driver side cover and needs to be connected directly to intake manifold vacuum to draw out the crank case pressure,,,,hence the term Positive Crankcase Ventalation,,,or PCV
As your PCV is sucking out crank case vapors from the driver side,,,,fresh air is replenished on the passenger side through that air cleaner connection you speak of.

[frog210]

I dont mean to highjack his thread
but this is how mine is
pics


as you can see on the drivers side theres a hose that goes to the carb

and i have a hose like he does in the pic on the passenger side but that goes to my air cleaner

and my air cleaner dosent have have s small air filter attached to the hose

[Firebirdjones]

Your PCV is hooked up correctly.

The hose on the passenger side that goes to your air cleaner (which isn't in the picture) Normally has a small fiber filter on the end with a factory air cleaner.

I'm betting you are running an aftermarket air cleaner (open element) in which case the hose from the valve cover actually connects INSIDE of the air filter element somewhere on the bottom of the base,,,therefore it doesn't need the little fiber filter on the end. On a factory air cleaner that hose would connect to the housing OUTSIDE of the filter element, hence the reason for the little fiber filter.

Hope that makes sense

[wilkin250r]

Frog, your setup is fine. The PCV is on the driver side, and it's correctly attached to a vacuum port on the carb. That vacuum is pulling air and vapors OUT of your crankcase, exactly as it's supposed to.

The hose on your passenger side is basically a vent, and it should NOT be attached to vacuum. When the PCV on the driver's side is pulling air out, the vent on the passenger side allows fresh air in. And it's attached to your air cleaner because you want any air coming in to be filtered, you don't want to be sucking dirt and dust into your crankcase.

Your setup is just fine.

[hopelessredneck]

i use a breather cap with a filer on it i got from proform

[bmfpeterson]

This is what I did, I wanted to run a clean setup as well. I wont get into all of everyone's ideas on running it or not...... I just made a tube that connected both sides and put a filter on it

[Firebirdjones]

Originally Posted by bmfpeterson

This is what I did, I wanted to run a clean setup as well. I wont get into all of everyone's ideas on running it or not...... I just made a tube that connected both sides and put a filter on it

Yep that works too. You don't HAVE to use a PCV. PCV is just an emissions device so you aren't venting your crank case vapors to atmosphere,,,,nothing more.

A couple breathers does the trick so long as your area doesn't do a visual inspection and the tree huggers complain Actually PCV's weren't even phased in on GM cars until 1969. Before that it was nothing but dump tubes and breathers.

The only time you have a mess with open breathers is if you have a ring control problem in one or more of your cylinders.

In all honesty open breathers are a better way to go as far as performance is concerned. Venting crank case vapors back to the intake track through a PCV dilutes the air/fuel charge, in more extreme cases it can cause pinging and poor performance.

[Number21]

What I'd really like is one of these on both sides:
http://www.ebay.com/itm/CHROME-ROUND...e56845&vxp=mtr

Right now I have something like that on the driver side, but it also connects to the air filter and it's a PITA. Is that really so bad? I can deal with a little oil mist on the valve covers.

I could definately use that extra vacuum port where the PCV plugs in too.

[Firebirdjones]

Originally Posted by Number21

What I'd really like is one of these on both sides:
http://www.ebay.com/itm/CHROME-ROUND...e56845&vxp=mtr

Right now I have something like that on the driver side, but it also connects to the air filter and it's a PITA. Is that really so bad? I can deal with a little oil mist on the valve covers.

I could definately use that extra vacuum port where the PCV plugs in too.

Yes you can run breathers on both sides if you wish, it serves the same purpose, you are just venting to atmosphere instead of introducing it back into your intake track.

It's basically the same thing Bmfperterson is doing that he linked a picture to. He just connected both sides with a breather. Those are also made with dual breathers. You see alot of that setup on roundy round cars and sprint cars....

[butch86]

i use these myself they cost a lil more but you get better ventalation than the 4 dollar ones at your LPS.

http://www.speedwaymotors.com/Push-I...r-Kit,626.html

[84_chevy]

So if you do disconnect the PVC hose from the carb would you need to readjust your carb, change jets? Do you just plug the carb up where the hose use to go?

[deth_1970]

one thing about disconnecting the pvc is that having it hooked up creates a vacuum in the block, which helps the rings stay seated, it is an emissions thing, but also some performance to be gained, prior to the pvc what was used was a downdraft tube, that went down the back of the block to slightly below the oil pan, the tube was cut at an angle, where a where a vacuum was created by air passing by it as the vehicle gained speed,
look at some performance stuff, they have crankcase evac systems that connect to the exhaust,
I would say, clean up the install, a little braided hose, or something but personally i would leave it in,
just my 2 cents worth

[Number21]

Originally Posted by deth_1970

it is an emissions thing, but also some performance to be gained

So there's potentially a HP/gas mileage gain with the PCV?

[Corts60]

Originally Posted by Firebirdjones

PCV is just an emissions device so you aren't venting your crank case vapors to atmosphere,,,,nothing more.

No it is not. What deth_1970 said is correct. The PCV keeps a vacuum on the crankcase to keep vapors from building pressure. That is why it is called POSITIVE crankcase ventilation and not just crankcase ventilation. Those old tubes were not "dump tubes", they were downdraft which drew a vacuum on the crankcase and they were not emissions devices at all. That is what PCV replaced because it was a way of achieving the same goal as the downdraft by ventilating the crankcase and also being better for the environment.

[Number21]

Originally Posted by Corts60

The PCV keeps a vacuum on the crankcase to keep vapors from building pressure.

Ok, can somebody explain to me why that is needed and what good it does? I don't doubt what you're saying, even an old Briggs and Stratton engine has a PCV setup. That said, I've also seen lots of engines without them....