Breathers, PCV question

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moparker

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I have seen many combos. Some no pcv just breathers. Also seen breathers with hoses running under the car. Some with breathers plumbed to air cleaner and some stand alone ones. What is the best combo for your engine to ventilate?
 
A PVC valve in one valve cover with a hose to the carb or intake manifold. The other valve cover will have a good breather. make sure that both are sealed good with grommets.
 
A PVC valve in one valve cover with a hose to the carb or intake manifold. The other valve cover will have a good breather. make sure that both are sealed good with grommets.
Same here but also run a hose to the aircleaner just to let the moisture get pulled out Just me.
 
Thats what I have on both. I have just seen so many combos. Thought I would throw it out there. Thanks for the response guys.
 
Really don't think there is a wrong way as long as there is a opening for the pvc to pull air through.
 
Really don't think there is a wrong way as long as there is a opening for the pvc to pull air through.

For some strange reason , my engine doesnt like the hose to the breather , I am now running two pcv`s , one is a store bought, and the other is kinda home made /with an alum. inline type valve.
The other cover , I have a sealed , with vacuum gauge line in it . The back of my throttle body has 2 distinct vacuum ports below the throttle blades .
Seems to like this set up w/ no breathers involved , running about 6'' of crankcase vacuum , 9-15 on the intake .
I tried a pan evac set up on one side , it didnt work w/ my mufflers-----------///-comments ?
 
1 pcv in a baffled valve cover, breather on opposite side. Pan evac only works with open headers.
 
-///-comments ?
Pan evac only works with open headers

@famous bob
Bob;
if you have 9-15 inches in the intake; that sounds like a fairly tame but fun street engine sorta like mine. If this is a street engine, all I know, then;
IMO
You need to provide fresh air to the crankcase/PCV system for the following reasons;
1) to get rid of the moisture that forms in there during running, that combines with the oil vapors to form acids, that destroy metals. Things like cam bearings and such.
2) the PCV is designed to provide bypass idle air. In your case it is just evacuating the crankcase. When the vacuum peaks, air no longer, rather, the correct amount of air, no longer enters the intake, and your low-speed circuit has to be adjusted to compensate for this lack of air. Inevitably this leads to low-rpm driveability issues. Now I know that you as a seasoned veteran of carb tuning,can get around these issues. But by the same token, you can restore the PCV function and tune for that.
3) consider what and why you are doing this. I'm guessing you are looking to recover a few horsepower,lost to windage. I know that you know there are better ways. You only need that power at WOT, so pan E-vacs are a much better solution.
4) IDK what 6inches vacuum translates to in pressure differential, but I have had a cam plug go on vacation at 4psi crankcase pressure, during testing, so don't recommend 4psi anymore, lol. And I know it is physically impossible so "suck" a cam plug in. However, I find it interesting that you can even achieve 6 inches crankcase vacuum, ..... and it makes me wonder if your system has the potential to do more, but achieves "only" 6 because it is already "sucking in" unfiltered air somewhere. Just wondering if your system is limited by the seals ability to work in reverse.

5) As for exhaust-powered E-vacs;
I had heard that the E-vacs only work on open headers. But if you know me, you know I question almost everything I have ever learned/been taught was true.
In my case, with full-length dual 3inch pipes, they worked just fine. In fact, they worked too good, sucking the oil right out of the valve covers. I couldda solved that, but here's the thing; my car is a streeter and burns rubber right thru first gear, and with 3.55s hits 50 mph @7000, and 65 in second-over is also 7000 and also still spinning. Obviously then, I don't need any more power, so I took them off.

6) other;
I ran the E-vacs simultaneously with a PCV and didn't have any other problems.
To solve my windage problems, I run a 7 qt pan, with just 5 qts in it, in conjunction WITH a tray.
And I don't do autocross anymore, just the one time,lol.
 
@famous bob
Bob;
if you have 9-15 inches in the intake; that sounds like a fairly tame but fun street engine sorta like mine. If this is a street engine, all I know, then;
IMO
You need to provide fresh air to the crankcase/PCV system for the following reasons;
1) to get rid of the moisture that forms in there during running, that combines with the oil vapors to form acids, that destroy metals. Things like cam bearings and such.
2) the PCV is designed to provide bypass idle air. In your case it is just evacuating the crankcase. When the vacuum peaks, air no longer, rather, the correct amount of air, no longer enters the intake, and your low-speed circuit has to be adjusted to compensate for this lack of air. Inevitably this leads to low-rpm driveability issues. Now I know that you as a seasoned veteran of carb tuning,can get around these issues. But by the same token, you can restore the PCV function and tune for that.
3) consider what and why you are doing this. I'm guessing you are looking to recover a few horsepower,lost to windage. I know that you know there are better ways. You only need that power at WOT, so pan E-vacs are a much better solution.
4) IDK what 6inches vacuum translates to in pressure differential, but I have had a cam plug go on vacation at 4psi crankcase pressure, during testing, so don't recommend 4psi anymore, lol. And I know it is physically impossible so "suck" a cam plug in. However, I find it interesting that you can even achieve 6 inches crankcase vacuum, ..... and it makes me wonder if your system has the potential to do more, but achieves "only" 6 because it is already "sucking in" unfiltered air somewhere. Just wondering if your system is limited by the seals ability to work in reverse.

5) As for exhaust-powered E-vacs;
I had heard that the E-vacs only work on open headers. But if you know me, you know I question almost everything I have ever learned/been taught was true.
In my case, with full-length dual 3inch pipes, they worked just fine. In fact, they worked too good, sucking the oil right out of the valve covers. I couldda solved that, but here's the thing; my car is a streeter and burns rubber right thru first gear, and with 3.55s hits 50 mph @7000, and 65 in second-over is also 7000 and also still spinning. Obviously then, I don't need any more power, so I took them off.

6) other;
I ran the E-vacs simultaneously with a PCV and didn't have any other problems.
To solve my windage problems, I run a 7 qt pan, with just 5 qts in it, in conjunction WITH a tray.
And I don't do autocross anymore, just the one time,lol.


You can run pan evacs with mufflers, and like everything else you have to do it correctly.

I run a closed system with a PCV and pan evacs and mufflers.
 
I run a PCV valve in one valve cover and a vent in the other. When we ran this engine on the dyno the PCV valve was worth 3 hp.
 
I have mopar performance valve covers that only have a vent hole in one of them and oil fill ports on both. Should I drill a hole in the other and put one hose with a pcv to the carb or intake manifold and the other side to the air cleaner? Other question i have is I'm running a open air filter with bottom and top lid, should I drill a hole in the bottom lid and put a fitting in?
 
I have mopar performance valve covers that only have a vent hole in one of them and oil fill ports on both. Should I drill a hole in the other and put one hose with a pcv to the carb or intake manifold and the other side to the air cleaner? Other question i have is I'm running a open air filter with bottom and top lid, should I drill a hole in the bottom lid and put a fitting in?

Get the grommet kit and put the PCV valve in the hole. Try to find a breather to fit in fill port. No need for a line to the air cleaner.
 
You should run a PCV from the valve cover to the carb and a hose from the other valve cover to a nipple on the air cleaner.

A good read here:

http://www.engineprofessional.com/articles/EPQ315_34-44.pdf

Tried that 3 times , because street hemi`s came out that way in 1968.
Like I said , my engine doesnt like it , acts like it has s vacuum leak when hooked up that way -.
Had to dwnsize my cam to get the fast 2.0 fuel inj. to work right a while back-
 
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I have mopar performance valve covers that only have a vent hole in one of them and oil fill ports on both. Should I drill a hole in the other and put one hose with a pcv to the carb or intake manifold and the other side to the air cleaner? Other question i have is I'm running a open air filter with bottom and top lid, should I drill a hole in the bottom lid and put a fitting in?
The hose to the air cleaner is sorta optional; you can run a breather on the valve cover with an atmospheric dump. The thing is;
at higher rpms,
and at WOT,
and especially as the rings get older,
the PCV system cannot keep up; so the breather starts to work backwards, and pukes blowby gasses, usually with plenty of oil in them, onto the valvecover, making a mess.
The other thing is, people forget to wash that breather out from time to time, not remembering that it is inhaling dirty air 100% of the time.By hooking it to the air cleaner, on the carb-side of the filter, it gets already filtered air. Furthermore, because that connecting pipe has a generous size, and is several inches long and all uphill, any oil in that column has a tendancy to drain back into the breather which is a good thing.
 
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If you run to the air cleaner you have to run to the filtered side of the cleaner
If you run to a filter on the valve cover you have to service it
The carb has to be tuned w or wo the pcv to the carb- right YR?
(YR is known to be picky on his tunes)
 
If you run to the air cleaner you have to run to the filtered side of the cleaner
If you run to a filter on the valve cover you have to service it
The carb has to be tuned w or wo the pcv to the carb- right YR?
(YR is known to be picky on his tunes)


Yes, the PCV valve changes the tune up.
 
On the passenger side Front of my 340 I have a PVC valve and on the other end of this valve cover I have a breather connected with a hose leading to the bottom of my engine. On the drivers side I have a breather on the front. I have been running this set up for 17 yrs and have had no issues...
 
@famous bob
Bob;
if you have 9-15 inches in the intake; that sounds like a fairly tame but fun street engine sorta like mine. If this is a street engine, all I know, then;
IMO
You need to provide fresh air to the crankcase/PCV system for the following reasons;
1) to get rid of the moisture that forms in there during running, that combines with the oil vapors to form acids, that destroy metals. Things like cam bearings and such.
2) the PCV is designed to provide bypass idle air. In your case it is just evacuating the crankcase. When the vacuum peaks, air no longer, rather, the correct amount of air, no longer enters the intake, and your low-speed circuit has to be adjusted to compensate for this lack of air. Inevitably this leads to low-rpm driveability issues. Now I know that you as a seasoned veteran of carb tuning,can get around these issues. But by the same token, you can restore the PCV function and tune for that.
3) consider what and why you are doing this. I'm guessing you are looking to recover a few horsepower,lost to windage. I know that you know there are better ways. You only need that power at WOT, so pan E-vacs are a much better solution.
4) IDK what 6inches vacuum translates to in pressure differential, but I have had a cam plug go on vacation at 4psi crankcase pressure, during testing, so don't recommend 4psi anymore, lol. And I know it is physically impossible so "suck" a cam plug in. However, I find it interesting that you can even achieve 6 inches crankcase vacuum, ..... and it makes me wonder if your system has the potential to do more, but achieves "only" 6 because it is already "sucking in" unfiltered air somewhere. Just wondering if your system is limited by the seals ability to work in reverse.

5) As for exhaust-powered E-vacs;
I had heard that the E-vacs only work on open headers. But if you know me, you know I question almost everything I have ever learned/been taught was true.
In my case, with full-length dual 3inch pipes, they worked just fine. In fact, they worked too good, sucking the oil right out of the valve covers. I couldda solved that, but here's the thing; my car is a streeter and burns rubber right thru first gear, and with 3.55s hits 50 mph @7000, and 65 in second-over is also 7000 and also still spinning. Obviously then, I don't need any more power, so I took them off.

6) other;
I ran the E-vacs simultaneously with a PCV and didn't have any other problems.
To solve my windage problems, I run a 7 qt pan, with just 5 qts in it, in conjunction WITH a tray.
And I don't do autocross anymore, just the one time,lol.

I want to stay with evac on the street, I like that it’s not affecting what gets to my intake with air/fuel mixture.
Currently my evac sucks a lot of oil from valve covers. It creates nice smoke effects from exhaust at high rpm. I have no baffles in the covers yet but I also plan to restrict the flow. Any ideas?
 
You should run a PCV from the valve cover to the carb and a hose from the other valve cover to a nipple on the air cleaner.

A good read here:

http://www.engineprofessional.com/articles/EPQ315_34-44.pdf
AS I stated earlier , my engine acts like its got a vacuum leak if I plumb to the breather --------
The pan eveac dropped my crankcase vacuum enough tjhat I started leaking oil again , ''the reason I like to run crankcase vacuum.''
Yeah ,its a street car , aint got the gears to be a racecar !
In the refining stages now------
 
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Any ideas?
On the street,
if your engine can spin the tires for most of first gear;then your engine already has more power than the chassis can handle; so, in that case you don't need more power;and if you have blow-by, then fix the engine.
My idea is to forget the E-vacs. Been there done that.

But if I had a modest-powered track-car;
I would find a better place to pull cc air from, rather than the valve covers.
IDK what the big-boys do.....
 
Anyone have any experience with oil separator's tied into the pcv ?
 
AS I stated earlier , my engine acts like its got a vacuum leak if I plumb to the breather

As in plumb the breather to the air cleaner?

A PCV valve is a vacuum leak.
pcv.gif
 
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