One or Two Breathers

-
73Swinger18

73Swinger18

✱ⓈⓌⒾⓃⒼⒺⓇ
Joined
Aug 15, 2016
Messages
578
Reaction score
217
Location
Camarillo, CA
I have a 318 that I'll be getting back from the shop soon. It'll be bored .030 over, new cam, flat top pistons, dual plane intake, 4 bbl, and stock heads with larger valves. I've decided to not install a PCV and just use breathers. Is there any benefit from using a breather on each valve cover instead of just one? I have two of them, but if there really is no benefit from using two, I'd like to just install one of them.
 
breathers with tubes to the exhaust? gotta say it - save that PCV stuff... unless you're drag racing only, you'll need it..
 
73Swinger18 said:
Nope. Just screw in breather in place of oil cap.
Click to expand...
I know it's a nice clean look - but it's not good for the street. You might want to read about PCV systems before moving too much further intoo this.. I run a pretty strong 360 on the street and it HAD dual breathers into the exhaust.. it was bad on the street. I retrofitted it back to PCV and have never looked back.
 
ScampMike said:
I know it's a nice clean look - but it's not good for the street. You might want to read about PCV systems before moving too much further intoo this.. I run a pretty strong 360 on the street and it HAD dual breathers into the exhaust.. it was bad on the street. I retrofitted it back to PCV and have never looked back.
Click to expand...
What issues did you have on the street?
 
You need to use the pcv valve.Why would you not want to use one.I can tell you from my experience from not using one it caused all kinds of oil leaks.Had to replace valve cover gaskets,intake gaskets and rear main seal in my engine because i did not use one from building up pressure in the crank case.Look at it this way it is not going to hurt to run one but it sure can hurt your engine if you do not
 
In addition to the above issues, expect excess sludging in the engine over the long term without a PCV and typical street use. And moisture that accumulates inside will add to the acids in the engine and increase wear rates. BTW, older engines from the early 60's and before had a breather AND a road draft tube that exited below the engine; the draft tube would get a vacuum pulled across the lower end when the vehicle was moving and so would suck some of the crankcase vapors out and prevent pressure induced leaks, etc. So running with just breathers is like going back to the 1920's or earlier in terms of crankcase ventilation....LOL

As for the PCV to use, you may not want the original 318's stock metal Mopar PCV if your cam is moderate. At stock idle vacuum levels, the PCV will close down some to avoid putting excess air into the intake and leaning the mixture. But the stock Mopar ones from the 60's/early 70's will open up to the cruise airflow level even at the lower idle vacuum that you get with a moderate cam; that will cause idle problems with too much air. There are PCV's that are designed to close down their air flow properly even with lower idle vacuum levels: Fram FV191 is an example.
 
Thank you all for your inputs. I understand that this topic has strong opinions and I knew I would get a bunch of replies telling me I need to use a PCV. I still do not want to install one. Here is why. I don't like the idea of anything other than fresh air going into the intake. I don't see how there could be so much much pressure build up with two breathers that it would cause oil leaks. The argument that you build up too much moisture without a PCV could also be argued that you draw in too much moisture with a PCV. I guess I'll go with two breathers to minimize the pressure build up. If it doesn't work out, I can always add it later.
 
Bad Sport said:
It isn't opinions, they were put there for a reason.

Expect to have oil on your engine without running it.

I know a guy that refused to run one and ran 2 breathers instead. Yup, you guessed it, oil was constantly being pushed out the breathers and made a nice mess!
Click to expand...
My valve covers have baffles on them to hopefully prevent making a mess.
 
It sounds like you had already made up your mind before you even ask for every ones opinion.I bet you will find out you need one
 
downsr said:
It sounds like you had already made up your mind before you even ask for every ones opinion.I bet you will find out you need one
Click to expand...
Read my first post. I did already have my mind made up. I asked if it was any better to have two breathers instead of just one. Everyone then decided to tell me that I needed a PCV instead of answering the original question except one person. Thank you 69_340_GTS.
 
if U do not want a pcv run 2 breathers. there will be no crankcase pressure, how can there be? change the oil sooner rather than later. let us know how it goes
 
Google adjustable PCV valve and read the info on the website. I have not used one of these and have no need to at this point. I run a stock piece. There can be issues with PCV valves but this product seems to solve them. Many have posted here with blown gaskets and oil all over thier nice clean engine bays. You seem set, but do not be surprised when the problems hit you!

Dual Flow Adjustable PCV Valve | M/E Wagner Performance Products
 
Last edited:
73Swinger18 said:
Thank you all for your inputs. I understand that this topic has strong opinions and I knew I would get a bunch of replies telling me I need to use a PCV. I still do not want to install one. Here is why. I don't like the idea of anything other than fresh air going into the intake. I don't see how there could be so much much pressure build up with two breathers that it would cause oil leaks. The argument that you build up too much moisture without a PCV could also be argued that you draw in too much moisture with a PCV. I guess I'll go with two breathers to minimize the pressure build up. If it doesn't work out, I can always add it later.
Click to expand...

Those weren't strong opinions other members were stating they were facts. You've just decided you know better and have chosen to ignore these facts, that's your right even though you are wrong.

You do realize the moisture the PCV is removing is created inside of your engine during the combustion process right??? Burning one gallon of gasoline produces over 1 gallon of water vapor. Just think you were worried about the minimal amount of moisture that is drawn into your engine by the PCV as being a problem. It's not, it's part of the solution. I suppose if you really wanted to be overly anal about the amount of moisture the incoming air that enters threw the breather you could install a air/water separator in the hose that goes to the breather.... If you really want to eliminate the water vapor inside of the crankcase beyond that its pretty simple, never start your car again.

Basically this sounds like its probably just a a case of we can explain it to you, but we can't understand it for you......
 
T-N-T said:
Those weren't strong opinions other members were stating they were facts. You've just decided you know better and have chosen to ignore these facts, that's your right even though you are wrong.

You do realize the moisture the PCV is removing is created inside of your engine during the combustion process right??? Burning one gallon of gasoline produces over 1 gallon of water vapor. Just think you were worried about the minimal amount of moisture that is drawn into your engine by the PCV as being a problem. It's not, it's part of the solution. I suppose if you really wanted to be overly anal about the amount of moisture the incoming air that enters threw the breather you could install a air/water separator in the hose that goes to the breather.... If you really want to eliminate the water vapor inside of the crankcase beyond that its pretty simple, never start your car again.

Basically this sounds like its probably just a a case of we can explain it to you, but we can't understand it for you......
Click to expand...
There are two sides to every story. Pros and cons for each. Try to keep it on topic "One or Two Breathers" and not that I don't understand your one dimensional train of thought.
 
Then put a draft tube on one side that will catch low pressure air under the car effectively drawing a vacuum. Oh thats right the PCV did the same thing only it burned it instead of dumping it into the air we breath. I think a case could be made that on a street driven car the amount of air flow available at the breathers under hood would be minimal thus rendering them innefective.
 
Last edited:
when the pedal is to the metal there is no vacuum, and the pcv is doing nothing. and that gallon of water per gallon of gas-99% of it goes out the exhaust
 
73Swinger18 said:
There are two sides to every story. Pros and cons for each. Try to keep it on topic "One or Two Breathers" and not that I don't understand your one dimensional train of thought.
Click to expand...

In this case the pro's for using a positive crankcase ventilation system are on one side of the story and the cons are on the other side though.

Btw there is always the vacuum pump system that can be used also. Tech: How External Vacuum Pumps Free Up Horsepower - EngineLabs

Since you would like me to disregard all of the benefits a PCV valve or other positive crankcase ventilation systems offers I will.

One breathers in each valve cover is definitely better then one in one and none in the other for whatever it's worth. Why not do two per side for a total of four. The more the merrier.

#PCV for the win
 
Marcohotrod said:
when the pedal is to the metal there is no vacuum, and the pcv is doing nothing. and that gallon of water per gallon of gas-99% of it goes out the exhaust
Click to expand...

So what percentage of the time you drive is spent at zero vacuum? If you have a drag car you can aspirate crankcase pressure to the headers or do the best solution which is use an external vacuum ventilation system like shown in this link which I just posted above this also.

Tech: How External Vacuum Pumps Free Up Horsepower - EngineLabs
 
You must log in or register to reply here.
-

Back
Top