Do you need to use a pvc valve
Thread Starter
Racer
Joined: Mar 2005
Posts: 471
Likes: 1
From: Hometown The best
Do you need to use a pvc valve
What are the consequencies of not using a pvc valve or the tube on the passenger side valve cover to the air cleaner. I have a new engine with aftermarket valve covers and air cleaner. In an effort to have a nice clean, uncluttered engine, I thought I might get rid of these two hoses,etc. I know they are there for polution purposes but would they hurt the engine by running without them?
Melting Slicks
Joined: Oct 2008
Posts: 2,154
Likes: 69
From: Regina Sk Canada
I run a PCV valve to the carb, and a push in breather on the other side. If i was to ever build another race type engine, 600 plus HP i would run a Vacuum pump. I have seen 22 extra hp with those on the dyno on some engines.
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Le Mans Master
Joined: Jun 2007
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From: Where it's always hot as Hell-South Louisiana.
St. Jude Donor '07-'08-'09-'10-'11-'12-'13
Just put this one in new, and plan to keep the pcv valve in place. I think this one is a looker with the pcv valve in place- swapped to the passenger side v/c.
http://paceperformance.com/i-5146077...e-package.html
http://paceperformance.com/i-5146077...e-package.html
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
The PCV keeps the oil smog out of your engine compartment. That will keep those new valve covers looking good longer....and you won't have to wipe oil film off everything in the engine compartment every few weeks. It does no harm to the engine or its performance. Keep it...
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
All engines have some degree of blowby. And that pressure has got to go somewhere. The question really is would you like to control where that vapor goes or not?
Ever seen an engine spit out its dipstick?
If you don't want to use a PCV valve, you could just run a hose from a valve cover down to the bottom of the frame somewhere. Leave it uncapped and pointed rearward, and air moving past it as you drive will create some vacuum. This is how it was done before the EPA crawled up our asses. Probably doesn't address the appearance issues you were going for though.
Ever seen an engine spit out its dipstick?
If you don't want to use a PCV valve, you could just run a hose from a valve cover down to the bottom of the frame somewhere. Leave it uncapped and pointed rearward, and air moving past it as you drive will create some vacuum. This is how it was done before the EPA crawled up our asses. Probably doesn't address the appearance issues you were going for though.
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
I read not long ago that there are three ways a car pollutes the air. It somewhat explains why we have Non- vented fuel tank caps, charcoal canisters and PCV valves
1. 60% from exhaust
2. 20% from fuel tank vapors
3. 20%from the crank case vapors
1. 60% from exhaust
2. 20% from fuel tank vapors
3. 20%from the crank case vapors
Pro
Joined: Apr 2006
Posts: 625
Likes: 49
From: Southern California
What are the consequencies of not using a pvc valve or the tube on the passenger side valve cover to the air cleaner. I have a new engine with aftermarket valve covers and air cleaner. In an effort to have a nice clean, uncluttered engine, I thought I might get rid of these two hoses,etc. I know they are there for polution purposes but would they hurt the engine by running without them?
I'll say my piece then get out before it all turns ugly..........again. I just don't have time for all the stupid arguments. Anyway, I do NOT run a PCV setup on my 781 HP, 540ci BBC street/strip motor. I just run two breathers, like I've done for many, many years on all my previous Hotrods. And I have never ever had any problems what so ever by doing that. Many, many of my buddies over the years have done, and are doing the exact same thing, also without any issue what so ever (though we do have to wipe off the valve covers now and again). Just look around at car shows, cruise-ins, races and your favorite local hangout. And you will see that most classic Hotrods run two breathers, and NOT a PCV setup.
In the real world, running without a PCV setup does NOT hurt the engine in any way, no matter what others will post here. If anyone says it hurts an engine, they do not know what they are talking about. And they are speaking only theoretically, and are repeating what they read somewhere. That makes them "internet engineers" and nothing more.
Running a PCV or not running a PCV will both work. Just make your own decision and run with it.
Last edited by 540 RAT; Apr 21, 2011 at 03:45 PM.
Burning Brakes
Joined: May 2008
Posts: 860
Likes: 0
From: Stratford Ontario
Pvc
Like Gordonm said, "Here we go again". This one may or may not go on and on for pages with no real resolution.
I'll say my piece then get out before it all turns ugly..........again. I just don't have time for all the stupid arguments. Anyway, I do NOT run a PCV setup on my 781 HP, 540ci BBC street/strip motor. I just run two breathers, like I've done for many, many years on all my previous Hotrods. And I have never ever had any problems what so ever by doing that. Many, many of my buddies over the years have done, and are doing the exact same thing, also without any issue what so ever (though we do have to wipe off the valve covers now and again). Just look around at car shows, cruise-ins, races and your favorite local hangout. And you will see that most classic Hotrods run two breathers, and NOT a PCV setup.
In the real world, running without a PCV setup does NOT hurt the engine in any way, no matter what others will post here. If anyone says it hurts an engine, they do not know what they are talking about. And they are speaking only theoretically, and are repeating what they read somewhere. That makes them "internet engineers" and nothing more.
Running a PCV or not running a PCV will both work. Just make your own decision and run with it.
I'll say my piece then get out before it all turns ugly..........again. I just don't have time for all the stupid arguments. Anyway, I do NOT run a PCV setup on my 781 HP, 540ci BBC street/strip motor. I just run two breathers, like I've done for many, many years on all my previous Hotrods. And I have never ever had any problems what so ever by doing that. Many, many of my buddies over the years have done, and are doing the exact same thing, also without any issue what so ever (though we do have to wipe off the valve covers now and again). Just look around at car shows, cruise-ins, races and your favorite local hangout. And you will see that most classic Hotrods run two breathers, and NOT a PCV setup.
In the real world, running without a PCV setup does NOT hurt the engine in any way, no matter what others will post here. If anyone says it hurts an engine, they do not know what they are talking about. And they are speaking only theoretically, and are repeating what they read somewhere. That makes them "internet engineers" and nothing more.
Running a PCV or not running a PCV will both work. Just make your own decision and run with it.
This the most honest answer you will see. I always run a PVC for that reason. I hate having the little bit of oil coming out of breather.But that is the only difference you will see in your car.You can take all the theory you want about this, and after you try it both ways the only thing that will come out of it is. The two breather metheod looks way cooler than a PCV set up, but you will always be cleaning the valve covers. I use dual PVC and never clean valve covers.The choice is really that simple.
Thread Starter
Racer
Joined: Mar 2005
Posts: 471
Likes: 1
From: Hometown The best
It sounds like I've got a couple of honest answers here. I think I'll try running with two breathers and no pvc for awhile. If I get much oil on my valve covers then I will hook up the pvc valve. It sounds like this could get to be a pretty involved discussion so you guys can continue on if you like but I have my answer. Thanks for the info.
Team Owner
Joined: Mar 2002
Posts: 24,160
Likes: 78
In the real world, running without a PCV setup does NOT hurt the engine in any way, no matter what others will post here. If anyone says it hurts an engine, they do not know what they are talking about. And they are speaking only theoretically, and are repeating what they read somewhere. That makes them "internet engineers" and nothing more.
Running a PCV or not running a PCV will both work. Just make your own decision and run with it.
Running a PCV or not running a PCV will both work. Just make your own decision and run with it.
Blowby will put exhaust gasses into your crankcase. This will introduce impurities into your oil and shorten its effective lifespan. Now with infrequently driven cars like ours which more likely than not get their oil changed based on time rather than mileage I would agree this is a non-issue. However on a daily driver that you want to 200k+ miles out of, the cumulative effect may be significant. However with that being said bear in mind that you, 540 RAT, are still giving positive pressure in your crankcase a way out by running breathers. You're just not actively evacuating the crankcase by applying vacuum to it. In other words, you're just taking the P out of PCV.
And yes, a lot of old cars got along just fine this way until emissions standards came into play.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
I run breathers too
Like Gordonm said, "Here we go again". This one may or may not go on and on for pages with no real resolution.
I'll say my piece then get out before it all turns ugly..........again. I just don't have time for all the stupid arguments. Anyway, I do NOT run a PCV setup on my 781 HP, 540ci BBC street/strip motor. I just run two breathers, like I've done for many, many years on all my previous Hotrods. And I have never ever had any problems what so ever by doing that. Many, many of my buddies over the years have done, and are doing the exact same thing, also without any issue what so ever (though we do have to wipe off the valve covers now and again). Just look around at car shows, cruise-ins, races and your favorite local hangout. And you will see that most classic Hotrods run two breathers, and NOT a PCV setup.
In the real world, running without a PCV setup does NOT hurt the engine in any way, no matter what others will post here. If anyone says it hurts an engine, they do not know what they are talking about. And they are speaking only theoretically, and are repeating what they read somewhere. That makes them "internet engineers" and nothing more.
Running a PCV or not running a PCV will both work. Just make your own decision and run with it.
I'll say my piece then get out before it all turns ugly..........again. I just don't have time for all the stupid arguments. Anyway, I do NOT run a PCV setup on my 781 HP, 540ci BBC street/strip motor. I just run two breathers, like I've done for many, many years on all my previous Hotrods. And I have never ever had any problems what so ever by doing that. Many, many of my buddies over the years have done, and are doing the exact same thing, also without any issue what so ever (though we do have to wipe off the valve covers now and again). Just look around at car shows, cruise-ins, races and your favorite local hangout. And you will see that most classic Hotrods run two breathers, and NOT a PCV setup.
In the real world, running without a PCV setup does NOT hurt the engine in any way, no matter what others will post here. If anyone says it hurts an engine, they do not know what they are talking about. And they are speaking only theoretically, and are repeating what they read somewhere. That makes them "internet engineers" and nothing more.
Running a PCV or not running a PCV will both work. Just make your own decision and run with it.
I run a breather on each overhead cover as this was a new crate 1970 LT1 and it did not have provision for a draft tube as the 327/360 HP I removed....the decision was to use the LT1 covers and mount the breather in those rather than damage my OE covers....For the Autorama I took off the LT1`s and put the OE covers back on it just for the completely stock FI look ....Never was concerned about blow by as it was a new brand new 370 HP engine....and even today there is no blow by ........
for anyone interested the engine in '1970 with all its accessories including bell housing and clutch except carb and fuel pump was $612.00 delivered from Dexter Chevrolet.....and long before the NCRS......
Now I've gone and done it....
Safety Car
Joined: Apr 2008
Posts: 3,908
Likes: 10
From: Charleston SC
When I had the PCV system setup on my 327 that previously had no provision for it, it idled high and rough, and would not tune. I tried everything and finally tied it back to the PCV I added.
I disconnected the PCV hose from the carb, and plugged up the port on the carb, and since then, have had no problems with the idle, acceleration, or tune-ability.
I did have the PCV hose on the driver's side, and the breather on the passenger side...does it matter which side?
Another possible issue is that the PCV elbow wasn't regulated...it was just a big hole, so maybe the carb was sucking too much air, and not allowing any vacuum in the engine?
I really don't know about this stuff...lol
I disconnected the PCV hose from the carb, and plugged up the port on the carb, and since then, have had no problems with the idle, acceleration, or tune-ability.
I did have the PCV hose on the driver's side, and the breather on the passenger side...does it matter which side?
Another possible issue is that the PCV elbow wasn't regulated...it was just a big hole, so maybe the carb was sucking too much air, and not allowing any vacuum in the engine?
I really don't know about this stuff...lol