Valve Cover Breather - Team Camaro Tech
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post #1 of 32 (permalink) Old Apr 24th, 15, 05:54 AM Thread Starter
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Bruce
 
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Valve Cover Breather

I have a PCV to the carb coming from the right valve cover and a "oil cap" pluging the left with no ventilation. Is this ok or not and if not what to suggest.
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post #2 of 32 (permalink) Old Apr 24th, 15, 06:37 AM
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Re: Valve Cover Breather

You should have an air inlet (breather) in the other valve cover. You could replace the oil fill cap with a removable breather, or install different VCs. Ideally 2 holes in one VC, one baffled for breather/PCV, one not baffled for oil fill. One baffled hole in the other VC for breather/PCV.


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post #3 of 32 (permalink) Old Apr 24th, 15, 06:38 AM
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Re: Valve Cover Breather

Quote:
Originally Posted by The Camaro Guy View Post
I have a PCV to the carb coming from the right valve cover and a "oil cap" pluging the left with no ventilation. Is this ok or not and if not what to suggest.
The factory standard was the PCV valve in the drivers side valve cover with a breather cap in the passenger side valve cover and the breather cap had a hose that connected to the air cleaner. I've read that which side each is located does matter, and I've read that it doesn't. I have mine plumbed the way the factory did it and it works well. I'd suggest you might be best off to find an oil cap that at least has breathers in the bottom of it, or even better one that you can plumb back to the air cleaner just in case. As long as the engine vents minimal crankcase vapors, the plain breather cap should be fine but if there is more crankcase venting need (due to blow-by), a cap with plumbing to the air cleaner will be beneficial. If there is enough blow-by and the PCV valve can't handle it all the pressure buildup in the crankcase could cause the next weakest link to allow the pressure to escape which could be as simple as blowing the PCV valve or oil cap out of the valve cover or as involved an a blown seal or gasket somewhere in the engine.

I see Al and I were replying at the same time

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post #4 of 32 (permalink) Old Apr 24th, 15, 07:03 AM
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Re: Valve Cover Breather

x2 what Scott said, and I might add that I also read depending on what year block, the oil side pressure is vented in different ways. early blocks had the old blow down tube, later the valve covers where used with breathers and then came the PCV to base of carb. On my 68 350 with the oil filler tube in front I use the pcv with hose on driver side that goes to base of Q-jet, and on the passenger side I have an aftermarket breather.

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Last edited by rgwiz; Apr 24th, 15 at 07:17 AM.
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post #5 of 32 (permalink) Old Apr 24th, 15, 09:23 PM
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Re: Valve Cover Breather

Quote:
Originally Posted by NH69Z28RS View Post
The factory standard was the PCV valve in the drivers side valve cover with a breather cap in the passenger side valve cover and the breather cap had a hose that connected to the air cleaner.

I've read that which side each is located does matter, and I've read that it doesn't.
Fred Ficarra pointed out that the reason the engine pulls air in on the passenger side breather is because it rotates counter-clockwise (looking from the front).

So air will come in the pass side and go out the pcv on the drivers side.
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post #6 of 32 (permalink) Old Apr 25th, 15, 05:29 AM Thread Starter
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Re: Valve Cover Breather

Thanks for all the info. I was thinking the same as all you guys but have slept awhile. The engine is a 71 454 to a 468 with tons of chrome and after market VC. Will make the changes.
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post #7 of 32 (permalink) Old Aug 1st, 16, 07:39 AM
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Re: Valve Cover Breather

Quote:
Originally Posted by The Camaro Guy View Post
Thanks for all the info. I was thinking the same as all you guys but have slept awhile. The engine is a 71 454 to a 468 with tons of chrome and after market VC. Will make the changes.
Reviving this thread to ask some advice. I also have a 454 (461 actually) and it was set up with the steel valve covers, oil filler cap on passenger side, PCV on the drivers. I was told I really should have a breather in the system. I bought a set of cast polished aluminum valve covers that came with three (3) threaded 1.25" holes, two, K&N type open breathers, two threaded billet adapters with a sort of baffle on the insert end, and a threaded filler cap.

So I installed the new valve covers, used Moroso blue gaskets, installed the PCV right where it was before (it's connected to rear of Carb base), and installed the two breathers. So despite being "baffled" I'm getting tiny droplets of oil dripping from both the breather filters. Obviously something is not correct in this setup. It's not a drag car, I'm not pushing the engine rpm at all... occasionally maybe 3800rpm. The breathers fit into a rubber hose which is clamped to the biller mount. No leakage at the base of the hose or at the mount which has a O-Ring seal. So should I remove the DS breather and put the oil filler cap on? It also has an O-Ring seal.

In my supercharged SVT Lightning, I had a catch can setup, no breathers at all, and of course a PCV valve. Engine surfaces dry as a bone, maybe a half cup of oil (if that) every 1000 miles.

Ideas?

Mike

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post #8 of 32 (permalink) Old Aug 1st, 16, 07:47 AM
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Re: Valve Cover Breather

Mike, I think we need to read what Lawrence is saying and posted, there needs to be a circulation system on our motors.
Breathers to the outside are doing just what you say, a few drops in them and they are for that purpose. Oil vapors need to be reclaimed . Some of us defeat the system of recovery.

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post #9 of 32 (permalink) Old Aug 1st, 16, 08:14 AM
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Re: Valve Cover Breather

Quote:
Originally Posted by 57vette View Post
Reviving this thread to ask some advice. I also have a 454 (461 actually) and it was set up with the steel valve covers, oil filler cap on passenger side, PCV on the drivers. I was told I really should have a breather in the system.
Was the oil filler cap on the passenger side of your original steel valve covers a solid cap with the notches that turns 45 degrees and locks in place or was it the type that has a nipple which pushes into a grommet in the valve cover. If it was the second one, was it solid on the underside or did it have holes in it?

Quote:
Originally Posted by 57vette View Post
I bought a set of cast polished aluminum valve covers that came with three (3) threaded 1.25" holes, two, K&N type open breathers, two threaded billet adapters with a sort of baffle on the insert end, and a threaded filler cap.

So I installed the new valve covers, used Moroso blue gaskets, installed the PCV right where it was before (it's connected to rear of Carb base), and installed the two breathers. So despite being "baffled" I'm getting tiny droplets of oil dripping from both the breather filters. Obviously something is not correct in this setup. It's not a drag car, I'm not pushing the engine rpm at all... occasionally maybe 3800rpm. The breathers fit into a rubber hose which is clamped to the biller mount. No leakage at the base of the hose or at the mount which has a O-Ring seal. So should I remove the DS breather and put the oil filler cap on? It also has an O-Ring seal.

In my supercharged SVT Lightning, I had a catch can setup, no breathers at all, and of course a PCV valve. Engine surfaces dry as a bone, maybe a half cup of oil (if that) every 1000 miles.

Ideas?

Mike
What kind of or how good are the baffles inside the new valve covers under the breathers, their job is to wick the oil out of the vapors allowing the oil to accumulate into droplets inside the valve cover and stay inside the engine. If they aren't doing their job the situation you describe can be the result.

Also, make sure your PVC valve is functioning and pulling crankcase vapors as it should be.

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post #10 of 32 (permalink) Old Aug 1st, 16, 09:41 AM
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Re: Valve Cover Breather

Quote:
Originally Posted by NH69Z28RS View Post
Was the oil filler cap on the passenger side of your original steel valve covers a solid cap with the notches that turns 45 degrees and locks in place or was it the type that has a nipple which pushes into a grommet in the valve cover. If it was the second one, was it solid on the underside or did it have holes in it?
It was the classic 45 degree turn and lock type.

Quote:
What kind of or how good are the baffles inside the new valve covers under the breathers, their job is to wick the oil out of the vapors allowing the oil to accumulate into droplets inside the valve cover and stay inside the engine. If they aren't doing their job the situation you describe can be the result.

Also, make sure your PVC valve is functioning and pulling crankcase vapors as it should be.
Here's a picture of the setup as it stands right now.



The PCV is brand-new, a week old. Here's a picture of the setup. The Valve Covers are Eddies, modded by Hardin to have the three (3) openings.



The billet breather adapters are pictures upside down to show the baffle design. They thread into the cast valve cover, seated on O-Rings, and the CNC part has AN-type flat sided so you can use an aluminum wrench to snug them down. When installed, the top edge is flared to allow a rubber hose to be pressed over the tube section. The breather is flared and fits into the 2" tall rubber hose, and its all held in place on the tube by a SS hose clamp. There are no leaks around the CNC part... oil is just dripping from the filter element right at the lower edge where the screen meets the bottom. My initial thought is maybe to increase the length of the hose? And maybe to use a pre-bent angle silicon hose so that the filter sits parallel to the ground?

Don... I'm all for experimenting to get it working right. It sounds like maybe I should only have a breather on the Passenger side? Thats easy enough to try. I can remove the DS breather and use the machined billet/O-Ring sealing oil "filler" cap you see in the rear valve cover.

Mike

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post #11 of 32 (permalink) Old Aug 1st, 16, 09:53 AM
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Re: Valve Cover Breather

I think the extra filter on the driver's side is messing you up. It's not allowing a vacuum to be pulled all the way from the passenger side. That spot should have a oil fill cover.

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post #12 of 32 (permalink) Old Aug 1st, 16, 10:26 AM
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Re: Valve Cover Breather

Quote:
Originally Posted by HawkX66 View Post
I think the extra filter on the driver's side is messing you up. It's not allowing a vacuum to be pulled all the way from the passenger side. That spot should have a oil fill cover.
This is easy to try... I'll pull the breather and replace with the cap. I'm not going to be driving much this week (I think), but I'll post back when I have a chance to put some miles on it.

Mike

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post #13 of 32 (permalink) Old Aug 1st, 16, 10:27 AM
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Re: Valve Cover Breather

I agree with Dave that the extra breather is contributing to the problem. The second thing I would question is the underside of those breather caps, I don't see anything there that would act as a true baffle. I think the vapors are passing right up into the filter elements and then they are accumulating the oil from the vapors and running to the lowest point and dripping on your engine/valve covers. There is nothing in that new setup that I see which would wick the oil out of the vapors allowing the oil to accumulate into droplets inside the valve cover and stay inside the engine, thus the oil is making it to the outside of the engine via those "breather caps".

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post #14 of 32 (permalink) Old Aug 11th, 16, 03:58 PM
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Re: Valve Cover Breather

Quote:
Originally Posted by NH69Z28RS View Post
I agree with Dave that the extra breather is contributing to the problem. The second thing I would question is the underside of those breather caps, I don't see anything there that would act as a true baffle. I think the vapors are passing right up into the filter elements and then they are accumulating the oil from the vapors and running to the lowest point and dripping on your engine/valve covers. There is nothing in that new setup that I see which would wick the oil out of the vapors allowing the oil to accumulate into droplets inside the valve cover and stay inside the engine, thus the oil is making it to the outside of the engine via those "breather caps".
On my supercharged Ford Lightning I had an aftermarket billet catch can. Blown engines are forever sucking oil into the plenum. Everyone I know with a Lightning runs a catch can.



Anyway, the catch can had SS mesh layered in between the intake and outlet so that oil and air would flow through and the oil would catch on the mesh and drip down into the reservoir section. I'd dump about 4 ounces of scummy oil every 1000 miles or so.

Just wondering if I stuffed the "neck" section with SS mesh it would wick any oil back to the rockers? I could get a SS fine screen to ensure nothing gets into the rockers.

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post #15 of 32 (permalink) Old Aug 11th, 16, 05:55 PM
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Re: Valve Cover Breather

Quote:
Originally Posted by 57vette View Post
Just wondering if I stuffed the "neck" section with SS mesh it would wick any oil back to the rockers? I could get a SS fine screen to ensure nothing gets into the rockers.
The only potential problem I see with stuffing the neck of the breather (I think that's what you mean when you mention the neck) is that there is not a lot of volume or area there to begin with, so you'd need to be careful to not over stuff and restrict the flow of air through the breather neck. I think it's worth a try to see what kind of difference it will make for your situation.

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