PCV Valve

TylerCharger69 · August 08, 2010, 09:08:42 PM

I was looking at some pics on the forum here and i noticed the most recent pic added was of an engine with no pcv valve but breather filters on both valve covers.....What are the pros and cons of this setup? Im running a pcv on one valve cover....and a breather on the other currently

terrible one · August 09, 2010, 05:46:26 PM

Bump because I'd like to know as well!

TylerCharger69 · August 13, 2010, 08:59:01 PM

TylerCharger69 · October 03, 2010, 06:59:14 PM

bump......again???

mikepmcs · October 03, 2010, 07:57:51 PM

This is what Ron says.
http://www.dodgecharger.com/forum/index.php/topic,63310.0.html

more
http://www.dodgecharger.com/forum/index.php/topic,70481.0.html

http://www.dodgecharger.com/forum/index.php/topic,7331.0.html

b5blue · October 04, 2010, 06:09:18 AM

I run mine per stock (440 .060 overbore with a six pack) and have never had any issues.

(Even before the rebuild with the nasty 509 cam)

TylerCharger69 · October 06, 2010, 07:59:09 PM

After reading the threads Mike posted.....is it safe to say that the entire PCV system is kind of the same premise as having to open up a big tin can of juice with and old "church key" on both sides so it can pour? I don't have blow by issues, but currently, I have a PCV on one valve cover and just a sealed cap on the other. Its clear I need to incorporate a breather on the opposing side. NOW......what would happen if a PCV valve was run from BOTH valve covers? I've seen this before too. Or would that be one pulling against the other and defeat the purpose? Very interesting thread!!! Thanks for posting those thread links Mike!!

gtx6970 · October 07, 2010, 08:24:33 AM

QuoteOr would that be one pulling against the other and defeat the purpose?

Yes

PCV system NEEDS incoming air to function properly. without a good crankcase evacuation system of some kind there is going to be seal leaks

If you run a PCV without an open vent on the opposite side, it is going to pull air from somewhere, probably past the rings. And regardless of how good of a ring seal one has, It will ALWAYS will have a small amout of blowby

Piston_Freddy · October 11, 2010, 04:42:45 PM

Can you see the problem here?

What will happen if I run the engine like this?Gasket leaks?

mikepmcs · October 11, 2010, 05:12:47 PM

besides that it needs a breather....
what's that rubber hose on the left side along the aircleaner?
is that a fuel line???

Piston_Freddy · October 11, 2010, 06:13:09 PM

Quote from: mikepmcs on October 11, 2010, 05:12:47 PM
besides that it needs a breather....
what's that rubber hose on the left side along the aircleaner?
is that a fuel line???

Yes that is a fuel line, whats wrong with it?

TylerCharger69 · October 11, 2010, 07:15:59 PM

Well.....a rubber hose being that close to the engine itself is a disaster waiting to happen. It may not be hot enough to burn through, but the heat is sure to weaken the integrity of the hose and cause it to become brittle and crack. Ive also HEARD, (note the emphasis on "heard") that a rubber hose in that location can cause vapor lock, but i haven't witnessed that myself. I have a rubber hose, but it's routed on the fender firewall and then straight to the carb with an inline filter also mounted on the firewall.

mikepmcs · October 11, 2010, 08:13:49 PM

yup need to get rid of that rubber hose and get some metal in there. at the very least get it up and off the motor away from the heat(until you get some other line).

chargd72 · October 11, 2010, 11:41:38 PM

To answer your question, I don't think you'll have gasket leaks since you don't have pcv vacuum to create negative pressure. Without a pcv or a breather your asking for some vapor build up which only leads to bad things. I'm not an expert, just relaying what I've read. But if I were you, I'd run the correct setup with breather on one side and pcv on the other.

Al · October 12, 2010, 05:25:30 AM

Quote from: chargd72 on October 11, 2010, 11:41:38 PM
To answer your question, I don't think you'll have gasket leaks since you don't have pcv vacuum to create negative pressure. Without a pcv or a breather your asking for some vapor build up which only leads to bad things. I'm not an expert, just relaying what I've read. But if I were you, I'd run the correct setup with breather on one side and pcv on the other.

What would be a good PCV valve to use? I got the standard replacement plastic one and it keeps falling out of the rubber grommet.
Al

Piston_Freddy · October 12, 2010, 05:30:31 AM

Thanks for the input! I will deal with these problems!

bull · October 14, 2010, 03:11:52 PM

Quote from: Al on October 12, 2010, 05:25:30 AM
Quote from: chargd72 on October 11, 2010, 11:41:38 PM
To answer your question, I don't think you'll have gasket leaks since you don't have pcv vacuum to create negative pressure. Without a pcv or a breather your asking for some vapor build up which only leads to bad things. I'm not an expert, just relaying what I've read. But if I were you, I'd run the correct setup with breather on one side and pcv on the other.

What would be a good PCV valve to use? I got the standard replacement plastic one and it keeps falling out of the rubber grommet.
Al

Sounds like you need a new grommet.

Al · October 15, 2010, 02:12:59 AM

Quote from: bull on October 14, 2010, 03:11:52 PM
Quote from: Al on October 12, 2010, 05:25:30 AM
Quote from: chargd72 on October 11, 2010, 11:41:38 PM
To answer your question, I don't think you'll have gasket leaks since you don't have pcv vacuum to create negative pressure. Without a pcv or a breather your asking for some vapor build up which only leads to bad things. I'm not an expert, just relaying what I've read. But if I were you, I'd run the correct setup with breather on one side and pcv on the other.

What would be a good PCV valve to use? I got the standard replacement plastic one and it keeps falling out of the rubber grommet.
Al

Sunds like you need a new grommet.

I got the cast aluminum Mopar valve covers, the grommet is new.

Piston_Freddy · October 15, 2010, 03:17:05 PM

Do mopar performance valve covers have baffles inside, to prevent oil coming through PCV valve in to the intake?

bull · October 15, 2010, 05:36:35 PM

Quote from: Al on October 15, 2010, 02:12:59 AM

What would be a good PCV valve to use? I got the standard replacement plastic one and it keeps falling out of the rubber grommet.
Al

Sunds like you need a new grommet.
[/quote]

I got the cast aluminum Mopar valve covers, the grommet is new.

[/quote]

Something's the wrong size then it seems. I got a new grommet and PCV valve from my Dodge dealer and it's tighter than my cheap brother.

Manifold · October 15, 2010, 09:19:30 PM

Quote from: Piston_Freddy on October 15, 2010, 03:17:05 PM
Do mopar performance valve covers have baffles inside, to prevent oil coming through PCV valve in to the intake?

I'm glad someone brought this up. If you add in a PCV valve and a breather, be sure you have baffles underneath each of them... unless you like an oily mess on the top of your valve cover. The aluminum MP valve covers have the provisions for baffles to be added. Didn't buy mine new, but the PO didn't bother to install a baffle under the breather (there was one under the PCV valve) and the top of the cover gets quite messy. Some self tapping screws and a piece of sheet aluminum made quick work of that issue.

myk · October 16, 2010, 03:06:10 AM

Quote from: mikepmcs on October 11, 2010, 08:13:49 PM
yup need to get rid of that rubber hose and get some metal in there. at the very least get it up and off the motor away from the heat(until you get some other line).

Wow, I've run a rubber line just like that since I've owned the car. I guess I'd better look into steel lines ASAP...

Piston_Freddy · October 16, 2010, 02:49:01 PM

Quote from: Manifold on October 15, 2010, 09:19:30 PM
Quote from: Piston_Freddy on October 15, 2010, 03:17:05 PM
Do mopar performance valve covers have baffles inside, to prevent oil coming through PCV valve in to the intake?

I'm glad someone brought this up. If you add in a PCV valve and a breather, be sure you have baffles underneath each of them... unless you like an oily mess on the top of your valve cover. The aluminum MP valve covers have the provisions for baffles to be added. Didn't buy mine new, but the PO didn't bother to install a baffle under the breather (there was one under the PCV valve) and the top of the cover gets quite messy. Some self tapping screws and a piece of sheet aluminum made quick work of that issue.

Thanks, probably my valve covers ain't got them.

Al · October 16, 2010, 03:02:42 PM

[/quote]

Sunds like you need a new grommet.
[/quote]

I got the cast aluminum Mopar valve covers, the grommet is new.

[/quote]

Something's the wrong size then it seems. I got a new grommet and PCV valve from my Dodge dealer and it's tighter than my cheap brother.
[/quote]

Are these the right ones? http://www.summitracing.com/parts/DCC-4529882/

TylerCharger69 · October 16, 2010, 04:36:57 PM

Those valve covers come with the baffles although you have to install them yourself. They are in a separate bag when they are brand new....at least mine came with them

mikepmcs · October 17, 2010, 06:59:07 AM

Quote from: TylerCharger69 on October 16, 2010, 04:36:57 PM
Those valve covers come with the baffles although you have to install them yourself. They are in a separate bag when they are brand new....at least mine came with them

concur. i have the same ones.

Piston_Freddy · November 03, 2010, 08:13:15 AM

Here's what happens if you don't install PCV valve or breather!

elacruze · November 03, 2010, 08:25:37 AM

One point that always gets confused in these discussions is the difference between 'Ventilation' and 'Vacuum'. PCV valves run to the air cleaner, not to manifold vacuum-there is very little pressure drop in the air cleaner so it will not produce any crankcase vacuum. Think of it more like a fan than a pump.

b5blue · November 03, 2010, 04:15:07 PM

My stock Six Pack connects the PCV to the base of the center carb. not the air cleaner. (FYI)

flyinlow · November 03, 2010, 05:47:20 PM

The PCV valve and the evaporative control canister are both benign emission controls. No draw backs , except the weight of the device and some occasional maintenance.

The positive crankcase ventalation valve draws a metered amount of air/vapor from the valve cover. This air/vapor is drawn from the crankcase and consists of air,oil vapor, and piston ring blow by (unburnt fuel and partially burnt fuel). In a healthy engine, at idle and part throttle there is not excesive blow by so some of the air/ vapor required by the PCV valve is drawn thru the opposite valve cover breather. The air/vapor is then run thru the engine and burned ,reducing emmisions.

The system helps keep gasoline and water vapor out of the crankcase and oil, extending the life of your oil and inderectly your engine. Carbs on a PCV valve equipt engines are calibrated for the air/vapor that gets drawn thru the system. Just plugging the port on the carb does change the A/F slightly. The system is operational at idle,part throttle and cruise when there is vacuum in the intake. It does not do much at WOT and does not reduce power output.

If you have a race car and don,t want to mess with it, fine. I would not remove it on a street car.

elacruze · November 03, 2010, 09:15:39 PM

Quote from: b5blue on November 03, 2010, 04:15:07 PM
My stock Six Pack connects the PCV to the base of the center carb. not the air cleaner. (FYI)

Does the PCV valve see manifold vacuum on that setup? I think I remember some others going to the carb too, but I thought they were above the throttle plates.

Brass · November 04, 2010, 12:08:31 AM

A short-term fix for the fuel line: cut another, larger hose lengthwise so you can slip it over the existing line like a sleeve. The extra insulation near the engine should be a little safer.

b5blue · November 04, 2010, 05:05:22 AM

Quote from: elacruze on November 03, 2010, 09:15:39 PM
Quote from: b5blue on November 03, 2010, 04:15:07 PM
My stock Six Pack connects the PCV to the base of the center carb. not the air cleaner. (FYI)

Does the PCV valve see manifold vacuum on that setup? I think I remember some others going to the carb too, but I thought they were above the throttle plates.

Yup...there is a slot in the base below the plates (runs to both barrel bores) that feeds the tube fitting for PCV. Sucks like a shop vac!

(I can post a pic later)

Manifold · November 04, 2010, 01:52:51 PM

Quote from: elacruze on November 03, 2010, 08:25:37 AM
One point that always gets confused in these discussions is the difference between 'Ventilation' and 'Vacuum'. PCV valves run to the air cleaner, not to manifold vacuum-there is very little pressure drop in the air cleaner so it will not produce any crankcase vacuum. Think of it more like a fan than a pump.

Incorrect. The PCV valve gets connected to the PCV port on the carb. The breather on the opposite valve cover is connected to the air cleaner and either has its own filter or draws air from inside the air filter to get its filtered air (if so equipped; an aftermarket breather cap has the filtering media inside the cap). The idea is the clean, filtered air is drawn into the engine and exits through the PCV valve on the opposite bank.

elacruze · November 04, 2010, 07:24:11 PM

I wish I knew what happened to my memory sometimes.

lighting74 · November 15, 2010, 09:30:36 PM

ford makes a oil cap breather to fit those valve covers i run the same ones went back to a older ford 302, 351 like a 80 model they have the ears on the bottom to fit in the valve covers and a open gromment in the top you put your pvc on the drivers side and on the passenger side a have a 90 degree plasctic elbow that is a rubber hose that goes and runs up and mounts to the bottom of the air cleaner it is a crankcase breather just like the factory came out with

Piston_Freddy · November 27, 2010, 04:57:36 PM

I bought a set of these grommets

What kind of PCV and breather I have to buy now?

Piston_Freddy · November 28, 2010, 07:01:34 PM

Quote from: Piston_Freddy on November 27, 2010, 04:57:36 PM
I bought a set of these grommets

What kind of PCV and breather I have to buy now?

Someone has to now?

terrible one · November 28, 2010, 07:47:18 PM

Hard to know without sizes, etc. Here's what I did when I got my old M/T covers. Someone had cut their own pcv/ breather holes and they were different sizes.

Measure the diameter of the hole in the valve cover.
Figure out the diameter of the PCV valve or breather neck you want to use.
Then, go to the parts store and get grommets with an OD the same as the hole in the valve cover and an ID the size of your PCV or breather neck.

If those grommets you got fit the hole in the valve cover, just get a breather or PCV that is the correct diameter to fit inside the grommet.

Piston_Freddy · December 06, 2010, 11:16:30 AM

I used Part Number :P5007921 grommets, they are .75 in. Inside Diameter.Parts store guys want to now PCV and breather part numbers....

terrible one · December 06, 2010, 12:08:24 PM

Quote from: Piston_Freddy on December 06, 2010, 11:16:30 AM
I used Part Number :P5007921 grommets, they are .75 in. Inside Diameter.Parts store guys want to now PCV and breather part numbers....

I still say just find a .75" diameter breather and/ or pcv valve that you like and use those. There should be some chrome rinky dink breathers in the chrome bullshit section of the auto store, can probably find a PCV in the HELP! section. Just find one you like the look of with a .75" diameter neck and there you go!

News:

PCV Valve