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PCV valve #145699 11/04/08 09:48 PM 11/04/08 09:48 PM
Joined: Jan 2003 Posts: 5,665 Detroit area 6PAX OP master
6PAX OP master Joined: Jan 2003 Posts: 5,665 Detroit area	How important or necessary is it to have a PCV valve on a street car? My 340 Dart has a breather on each valve cover but I was told today that I should have a PCV valve in place of one of the breathers. Is this true?

Re: PCV valve [Re: 6PAX] #145700 11/04/08 10:39 PM 11/04/08 10:39 PM
Joined: Jan 2007 Posts: 7,664 IN A ahy master
ahy master A Joined: Jan 2007 Posts: 7,664 IN	Forced venting from a PCV valve helps remove water vapor and other contaminants from the crankcase. It helps the oil and engine last longer. Breather only works but PCV is better if you're putting any miles on.

Re: PCV valve [Re: 6PAX] #145701 11/04/08 10:42 PM 11/04/08 10:42 PM
Joined: Dec 2003 Posts: 5,314 Carstairs, Alberta, Canada dave571 master
dave571 master Joined: Dec 2003 Posts: 5,314 Carstairs, Alberta, Canada	Quote: How important or necessary is it to have a PCV valve on a street car? My 340 Dart has a breather on each valve cover but I was told today that I should have a PCV valve in place of one of the breathers. Is this true? It's true. No reason not to run one on a street car. It won't hurt your performance in any way, AND it will help to keep you from pushing the gaskets out with excessive crankcase pressure.

Re: PCV valve [Re: dave571] #145702 11/04/08 11:23 PM 11/04/08 11:23 PM
Joined: Jan 2003 Posts: 33,005 Grand Prairie,Texas stumpy I Win
stumpy I Win Joined: Jan 2003 Posts: 33,005 Grand Prairie,Texas	Better to have one than not.

Re: PCV valve [Re: stumpy] #145703 11/05/08 12:50 AM 11/05/08 12:50 AM
Joined: Jun 2004 Posts: 893 Tustin, CA P pishta super stock
pishta super stock P Joined: Jun 2004 Posts: 893 Tustin, CA	Youll never get excessive crankcase pressure running no PCV if you run breathers. The PCV, running to a fitting under your carb always seemed to me to screw up your A/F ratio when it opened (When exactly does it open, at what vacuum level?) almost like a controlled vacuum leak. Seems it would lean out when it finally opens with little manifold vacuum. I gut mine (pull the spring and ball) and run it to a port above the butterflys, or even into the air cleaner housing. I dont put many miles on mine, but my '57 Ford 312 had only a breather pipe that went straight down, used the forward motion of the car to produce a vacuum across the tip to vent the crankcase. That car idled like my Lexus, smoooth. You could even run a header evac system from one side and a dual breather on the other. 12 Grand Caravan 06 T&C 02 T&C 96 Breeze 65 Barracuda "S"

Re: PCV valve [Re: pishta] #145704 11/05/08 01:00 AM 11/05/08 01:00 AM
Joined: Dec 2003 Posts: 5,314 Carstairs, Alberta, Canada dave571 master
dave571 master Joined: Dec 2003 Posts: 5,314 Carstairs, Alberta, Canada	"Youll never get excessive crankcase pressure running no PCV if you run breathers" is simply untrue. Seen it lots of times. Yes road draft tubes work, and so do header evac systems. Both much better than nothing at all. Years of use on all kinds of carbed applications have proved a pcv doesn't screw up the air fuel ratios, keeps the oil cleaner, and reduces crankcase pressure. To each thier own

Re: PCV valve [Re: dave571] #145705 11/05/08 01:37 AM 11/05/08 01:37 AM
Joined: Jun 2004 Posts: 893 Tustin, CA P pishta super stock
pishta super stock P Joined: Jun 2004 Posts: 893 Tustin, CA	Enlighten me on how a 2 breather vented crankcase can build enough pressure to blow out a rail gasket. I cant picture it on a healthy ringed motor. 12 Grand Caravan 06 T&C 02 T&C 96 Breeze 65 Barracuda "S"

Re: PCV valve [Re: pishta] #145706 11/05/08 06:59 AM 11/05/08 06:59 AM
Joined: Jan 2003 Posts: 27,728 places 7 79powerwagon Too Many Posts
79powerwagon Too Many Posts 7 Joined: Jan 2003 Posts: 27,728 places	I ran only breathers on my poly 318, and hated it! I use PCV on everything else, much cleaner...

Re: PCV valve [Re: pishta] #145707 11/05/08 07:52 AM 11/05/08 07:52 AM
Joined: Jan 2003 Posts: 338 Montreal Quebec STROKIE enthusiast
STROKIE enthusiast Joined: Jan 2003 Posts: 338 Montreal Quebec	Quote: Enlighten me on how a 2 breather vented crankcase can build enough pressure to blow out a rail gasket. I cant picture it on a healthy ringed motor. I use 2 breathers on my stroker and never blew out a gasket...

Re: PCV valve [Re: pishta] #145708 11/05/08 09:02 AM 11/05/08 09:02 AM
Joined: Nov 2004 Posts: 25,050 Texas GoodysGotaCuda 5.7L Hemi, 6spd
GoodysGotaCuda 5.7L Hemi, 6spd Joined: Nov 2004 Posts: 25,050 Texas	Quote: Enlighten me on how a 2 breather vented crankcase can build enough pressure to blow out a rail gasket. I cant picture it on a healthy ringed motor. In my opinion, there is nothing to actually evacuate the gasses out of the crankcase. Regardless of the healthy rings, a cold startup and probably a few hard throttle runs will still leave you with enough crankcase gasses down there to cause some issues. Possibly not to blow out any seals, but it will surely shorten the life of your oil. Also will probably find a nice fine oil mist under the hood...atleast things won't rust! Again, just my 1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi 2020 RAM 1500 [img]https://i.imgur.com/v9yezP9.jpg[/img]

Re: PCV valve [Re: GoodysGotaCuda] #145709 11/05/08 10:39 AM 11/05/08 10:39 AM
Joined: Jan 2003 Posts: 21,088 Niles , Ohio T therocks oh wait.but hey.lets see.oh yeah.
therocks oh wait.but hey.lets see.oh yeah. T Joined: Jan 2003 Posts: 21,088 Niles , Ohio	My kid runs 2 breathers on his 62 300.That 413 has never been apart runs 13s thru the 1/4 and gets tons of street miles .Its been run like that for at least 10 years.I run 2 also on my built 440 and no problems.The built 360 in the truck runs the same thing.No leaks and no excessive pressure.Rocky Chrysler Firepower

Re: PCV valve [Re: 6PAX] #145710 11/05/08 10:56 AM 11/05/08 10:56 AM
Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska R RapidRobert Circle Track
RapidRobert Circle Track R Joined: Nov 2003 Posts: 36,041 Lincoln Nebraska	I believe in them but I've wanted to run a exhaust evac on one side a closed breather on the other & eliminate the controlled vac leak(PCV) into the eng to "improve" the A/F ratio but they've been in use for decades with no A/F ratio problems so maybe I should leave well enough alone. live every 24 hour block of time like it's your last day on earth

Re: PCV valve [Re: 6PAX] #145711 11/05/08 11:48 AM 11/05/08 11:48 AM
Joined: Aug 2006 Posts: 247 DuPont, Washington D DZJim enthusiast
DZJim enthusiast D Joined: Aug 2006 Posts: 247 DuPont, Washington	PCV i.e. "positive" crankcase ventilation. So you can provide "positive" crankcase ventilation with a draft tube when the car is moving using the so-called "venturi effect". When its not moving, no "positive" crankcase ventilation--just crankcase ventilation. Most of us wouldn't remamber sitting at a stoplight in a cloud of smoke back in the 50's and early sixties, but I do. Worn-out engines with blowby pumping smoke out the draft tube. The center of the road at the stoplights would be smoothly covered with the tar from leakers and smokers. You'd be amazed at the air pollution we lived with and thought nothing about back in the day. Most people smoked too! Insane. Its better now. I can tell there is an old carbureted vehicle ahead on the freeway by the smell. I like the new ones better. No smell. Less air pollution. So an engine will run OK with only a couple of valve cover breathers providing crankcase ventilation. Why did the car companies go to the expense of installing draft tubes if a couple of valve cover breathers would have sufficed? Maybe it was better engineering? My $0.02

Re: PCV valve [Re: DZJim] #145712 11/05/08 02:26 PM 11/05/08 02:26 PM
Joined: Apr 2008 Posts: 1,195 Snowing in the north! D Dart 340 moparts member
Dart 340 moparts member D Joined: Apr 2008 Posts: 1,195 Snowing in the north!	I could not get my car to idle lean enough when I bought it. It had 2 breathers in it. Put in a PCV valve and bingo, much better now. 25 years ago my 'Cuda 340 didn't have a PCV in it and every now and then I'd find the dipstick tube pushed up. Put a valve in it and that problem went away. Go figure. To each his own, but I will always run one now.

Re: PCV valve [Re: Dart 340] #145713 11/05/08 08:26 PM 11/05/08 08:26 PM
Joined: Jan 2003 Posts: 338 Montreal Quebec STROKIE enthusiast
STROKIE enthusiast Joined: Jan 2003 Posts: 338 Montreal Quebec	Quote: I could not get my car to idle lean enough when I bought it. It had 2 breathers in it. Put in a PCV valve and bingo, much better now. 25 years ago my 'Cuda 340 didn't have a PCV in it and every now and then I'd find the dipstick tube pushed up. Put a valve in it and that problem went away. Go figure. To each his own, but I will always run one now. I use 2 breathers and my idle is very good I don't understand when you put a PCV you have a better idle... You inject oil fume in your air fuel mixture... I think is't not the best octane booster..

Re: PCV valve [Re: STROKIE] #145714 11/05/08 09:50 PM 11/05/08 09:50 PM
Joined: Jan 2003 Posts: 33,005 Grand Prairie,Texas stumpy I Win
stumpy I Win Joined: Jan 2003 Posts: 33,005 Grand Prairie,Texas	If two breathers were efficient why would the manufactuerers of most all makes go to a PCV system? PCV is a better way so why not use it?

Re: PCV valve [Re: stumpy] #145715 11/05/08 10:04 PM 11/05/08 10:04 PM
Joined: May 2007 Posts: 209 New Zealand S solidcam enthusiast
solidcam enthusiast S Joined: May 2007 Posts: 209 New Zealand	Auto makers were forced to design systems that wouldn't release crankcase gases into the atmosphere for emission purposes.

Re: PCV valve [Re: STROKIE] #145716 11/06/08 12:17 AM 11/06/08 12:17 AM
Joined: Apr 2008 Posts: 1,195 Snowing in the north! D Dart 340 moparts member
Dart 340 moparts member D Joined: Apr 2008 Posts: 1,195 Snowing in the north!	Quote: Quote: I could not get my car to idle lean enough when I bought it. It had 2 breathers in it. Put in a PCV valve and bingo, much better now. 25 years ago my 'Cuda 340 didn't have a PCV in it and every now and then I'd find the dipstick tube pushed up. Put a valve in it and that problem went away. Go figure. To each his own, but I will always run one now. I use 2 breathers and my idle is very good I don't understand when you put a PCV you have a better idle... You inject oil fume in your air fuel mixture... I think is't not the best octane booster.. Why does your car speed up when you open a plugged vacuum port on your carb? Same reason. It's still air mixing with it. I have a very high lift cam and low vacuum at idle.

Re: PCV valve [Re: Dart 340] #145717 11/07/08 03:24 AM 11/07/08 03:24 AM
Joined: Apr 2007 Posts: 560 MI M marklock I tried too hard for a custom title
marklock I tried too hard for a custom title M Joined: Apr 2007 Posts: 560 MI	no pcv valve and no problems, doesn't see alot of miles though. 4797993-dart040-1.jpg (1775 downloads)

Re: PCV valve [Re: marklock] #145718 11/07/08 05:42 AM 11/07/08 05:42 AM
Joined: Jan 2003 Posts: 27,728 places 7 79powerwagon Too Many Posts
79powerwagon Too Many Posts 7 Joined: Jan 2003 Posts: 27,728 places	Can you run two breathers and no PCV? Yes. Do you want to? Not if you can help it. Why? It's dirty! That is the reason I hated it, could never keep anything clean.

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