PVC/Breathers/Oil Fill ?? Confused!!

[6600DURAMAX]

Have a 468BBC, just put my new "fabricated aluminum" valve covers on. Neither have holes yet and I know they need them but I want the cleanest look possible.

What are my options?? Do I have to run a pvc or can I just run breathers in each side??

I have read some old post but am still confused.

Help guys want to get these drilled before I finish polishing them


thanks guys

[leddzepp]

If for no other reason, you need PCV to keep your engine compartment from getting dirty with oily residue. Use a breather cap on one side (which will actually be taking in clean air) and on the other run a vacuum line to the carburetor. There are other reasons to run PCV, and i am sure people will chime in with that info as well.

[Senator350]

ummmm... I would immediately abort any plans to drill holes in your VC's (valve covers) if they are already installed. You'll get metal filings EVERYWHERE!

I don't think you NEED a PCV (pollution control valve) as I have run a couple small blocks with just breathers on each side.

[6600DURAMAX]

Valve covers are currently off the truck as I am in the process of polishing them. Here is a pic of the original set up with the old valve covers.

[Senator350]

Sorry for the double post, edit feature just went "bonk"

Forgot to mention...
you want a vent on each side, whether breather/PCV or breather/breather.


If you don't have baffles, maybe Ledzepp is right... you'll probably have the neighborhoods dirtiest engine.

You need properly baffled, properly vented VC's.

PCV Pollution Control Valve is to burn off the gasses in your crankcase. You don't need it, unless you're getting smogged or something.

BTW, I like your FPR mounting location. I'm stealing that.

[CSGAS]

You will want a PCV--it stands for positive crankcase ventilation actually, and that venting of pressure improves performance as well. It's been on Hemi's since the 50's, and I'm sure there are other engines I'm less familiar with that tried one earlier than that.

It doesn't have to go in your valve covers though. Those early Hemi's had seperate valley covers from the intakes, and the PCV functions (vents some years, valves others) were placed there. If the intake you are using gives you a spot with direct access to the valley (not just a port to the runners) then you may consider hiding a valves there.

If you have a front filler tube, I've seen some PCV valves plumbed tot he side of that tube and a breather set on top of it so the valve covers could stay smooth.

To determine what you need, think of breathers as the way air gets into the Crankcase to "fill" or replace low pressure, and PCV as the way to release excess pressure without making a mess.

[El Jay]

You need a PCV (Positive Crankcase Ventilation) valve on 1 side and a filtered breather on the other.
That way, you be pulling clean, filtered air in to & through the engine and then sucking into the intake.

If you don't run a PCV system you can very easily build up enough crankcase pressure to force oil out of places you would have never believed.

I guess I'm just pretty much saying the same thing leddzepp said.

Oh, yeah; I use my filtered breather as an oil fill also.

[CSGAS]

I see you posted a picture while I was typing that post...I don't see a reasonable alternative spot for the breather or PCV on that intake.

You do have an option instead of the top surface of the valve covers...you have to check your rocker interference anyway no matter what position you use; if you check carefully there may be a spot on each of the valve cover sides closest to the intake to put hole that are less "in yer face"...that's been done before too.

[JoeMamma]

I use a PCV valve on one valve cover, and a breather/filter on the other cover. I used to hate the oiley smell in the cab. Plus....no oil residue on the firewall.

If you plan on drilling out one of the valve covers for a PCV valve, be sure to make up a small splash shield directly under the opening of your drilled hole. If a splash shield is not used, raw oil will be sucked into the PCV valve. I found this out the hard way a few years back.

Another plus is making Al Gore a happy camper !!

Joe M.

[Longhorn Man]

Your crank case is filled with misted oil particles, fuel vapors, and residude from the conbustion that gets by your rings. All this is normal. When all this mixes together, along with water vapor from the humidity in the air, it becomes acidic, and contaminates your oil.
The PCV sucks all that crap out of the air that is trapped in the crankcase, and feeds it into the incoming air/fuel that is headed to the comustion chaimber for burning.
For simplicity, we'll compair the crankcase with your kitchen after you burned your dinner real good. I mean REAL good, thick smoke, hardly see across the room, let alone inhale.
1. You can open one window, and that'll let some air out.
2. Or you can open 2 windows... that's be better.
3. Or, you can open both windows, and place a window fan in one aimed out, to suck all the smoke out, while clean, fresh air comes in the other window on the other side of the room.

#1 is your engine with one breather.
#2 is your engine with 2 breathers.
#3 is one breather, and a PCV valve.

While this IS a polution control device, (and reqired federally in all 69 and later trucks, 64 and later in cars) it is one that has no performance killing drawbacks, and HELPS your engine last longer and run cleaner. And by cleaner, i don't mean smog, I mean crap in the oil, getting ground into the bearings and cylinder walls, causing poor oil pressure and less performance.

Personally, I don't see them as being all that ugly. you can get alluminum ones from places like Jeggs or summit, and then steel braided hose if it pleases your eyes a little more, but in my personal opinion, it is a must have for anything but an all out show truck that rides in a trailer to get to the show.

[El Jay]

Originally Posted by Longhorn Man

Your crank case is filled with misted oil particles, fuel vapors, and residude from the conbustion that gets by your rings. All this is normal. When all this mixes together, along with water vapor from the humidity in the air, it becomes acidic, and contaminates your oil.
The PCV sucks all that crap out of the air that is trapped in the crankcase, and feeds it into the incoming air/fuel that is headed to the comustion chaimber for burning.
For simplicity, we'll compair the crankcase with your kitchen after you burned your dinner real good. I mean REAL good, thick smoke, hardly see across the room, let alone inhale.
1. You can open one window, and that'll let some air out.
2. Or you can open 2 windows... that's be better.
3. Or, you can open both windows, and place a window fan in one aimed out, to suck all the smoke out, while clean, fresh air comes in the other window on the other side of the room.

#1 is your engine with one breather.
#2 is your engine with 2 breathers.
#3 is one breather, and a PCV valve.

While this IS a polution control device, (and reqired federally in all 69 and later trucks, 64 and later in cars) it is one that has no performance killing drawbacks, and HELPS your engine last longer and run cleaner. And by cleaner, i don't mean smog, I mean crap in the oil, getting ground into the bearings and cylinder walls, causing poor oil pressure and less performance.

Personally, I don't see them as being all that ugly. you can get alluminum ones from places like Jeggs or summit, and then steel braided hose if it pleases your eyes a little more, but in my personal opinion, it is a must have for anything but an all out show truck that rides in a trailer to get to the show.

Great analogy, Andy.

[Longhorn Man]

Thank you... I've found it to be the absolute best way to explain why it is needed. It's just a PITA to type it out every 6 months or so.

[Highsteel]

Very informative Longhorn Man!

When I first got my 71 it had 2 PCV valves. One plumbed to the base of the carb and the other side plumbed through the spacer between the carb and the air cleaner. The later of which has been replaced with a breather/oil filler leaving the spacer plumbing to be used by a more economical apparatus.

[Longhorn Man]

highsteel...
the actual correct way the PCV was done from the factory is like what you described... although, I think you described an actual PCV in the fresh air tube too? If so, that's not right.
The breather is the lazy, and most common way we do it on a modified vehicle, and in reality, is not smog compliant. The correct way is a tube from the valve cover, to the air cleaner base, or on these trucks, onto the sub stack under the air cleaner.
This brings in cleaner air than a breather could ever provide, and if blow by were to get bad (as the engine ages) oil can get pushed out the breather and puddle and/or burn off externally, like on the exhaust. The EPA would rather have that blow by burned off in the engine, where it can be measured in a smog test, and fail, thereby sent to be rebuilt./junked.

[6600DURAMAX]

So I should buy these inserts and then run a PCV in one side that goes to the base of the carb and then run a breather on the other side. I looked and they do have some pretty trick looking PCV valves. I think I need to run these from WYSCO since I do not have any internal baffles in the valve covers.

Is that correct

thanks guys

[CSGAS]

That type of insert would double as both a baffle and a PCV adapter, yes. You may have to be picky about the mount size/type for your breather if you use the same insert for it.

Most common aftermarket breathers are intended for a 1.22 or 1.25 in grommet, and slip in. Others are available to twist in instead of an oil cap, same hole with two tabs. Both of those would require an add-on baffle plate. Another style clamps on to a 3/4 in tube...and it looks like using that insert would mean sticking a short length of 3/4 in OD tube (thin wall aluminum is fine, this isn't structural) and clamp one of these last type to it.

[6600DURAMAX]

Excellent, will order them and then decide on a pcv and breather combo. Thanks guys for helping keep the motor clean

[6600DURAMAX]

BIG OIL LEAK PROBLEMS

I am running the Wysco baffles on both sides of the engine. The drivers side has the PCV vale which in turn is plumbed to my carb spacer. The pass. side is running just a breather. I HAVE OIL EVERYWHERE. When I just drive it normal it just barely leaks, when I jump on it 3500rpm and up, oils seems to squirt out everywhere, then the electric fans blow it all over the motor, firewall, headers. etc..........

THIS IS DRIVING ME NUTS, all gaskets on the motor are brand new felpro rubber with the metal.

Am I building up to much crankcase pressure?? If so how do I get rid of it.

Please help guys, I cant stand taking this thing to the show only to spend 20 minutes wiping the oil off it.

I can take some pics if that will help any

Advice??

[6600DURAMAX]

No one has any ideas???

[SCOTI]

Oil everywhere is a broad description. Is oil being forced out of gasketed areas? Is it more prominent in certain areas?

I've heard more than one tale of the breather style baffles not being adequate shielding & allowing oil seepage.

[Longhorn Man]

agreed... oil everywhere could be an intake end seal, valve cover, fuel pump falling off, ANYTHING... what part of the engine does it seem to be starting at?

[mclairmo]

I have my pcv valve in the driver side valve cover and an elbow in the passenger side plumbed to the base of my open element air cleaner and no problems. Had a buddy back in the day that installed those stupid cork intake manifold end seals but forgot to take the clear wrapping off them. Guess what happened? Back one leaked like a river. Had to pull the intake off again and lay a bead of silicone down instead. No more leaking. Also, check to see if you have the gasket under the distributor.

[leddzepp]

Is this a new problem? I noticed your last post in this thread before today was April 21....or did you install this recently and it has been happening ever since?

[Spoof]

Is it possible the plumbing is incorrect? Maybe a vacuum gauge to the intake on the carb base would at least prove air is being drawn. It sounds as if internal pressure is forcing the oil out, mind you I've just had leaky valve covers that only leaked at higher rpms. hmmmm

[6600DURAMAX]

Let me see if I cna priovide some more useful information.
Oil Everywhere - It appears to be coming from the front of the motor only, but the electric fans are blowing it everywhere, which is another reason it is hard to pinpoint a location. I mean oil is literally all over the alternator, water pump, inner fenders!!! Firewall, etc.....

Motor was taken out at the begining of the year for a freshen up, replaced all gaskets with the Blue Rubber Felpro

I took apart the breather on the pass. side (it is the aluminum billet typw that screws together) and it is dry, very little oil at all, almost none.

It seems a vacuum gauge would tell the story, need to go to the parts store and pick one up I guess. Maybe those internal baffles do not releive enough pressure.

This is crazy. I will post some pics later

thanks guys, keep the suggestions coming.

I might even go to a different set of valve covers with the typical style breather and see if that helps.