Valve cover breather/PVC question

[Eliteman76]

OK...I have a minor headache. Nothing major, but I have a new set of stock type Ford Motorsport covers on my 351c in my GTS.
They use a push in type PVC and I have a street car that I like to have fun with. No racing...um, well, just street fun.
Anyways, what would be causing a oil mist to collect around the breather? I have it set up like the original breather setup, feeding the hose to the port on my Edlebrock carb. Either I never noticed it much with the original covers, or ?

I have been looking for a better solution, and saw Moroso's screw on type breathers, but they say race only.
I also considered saying to heck with it, and get AN vent fittings, and run pushloc hose to a breather tank on the radiator support.

For a street car, I wouldn't think I would have this sort of issue. And all the seals are new. Everything seals and fits tight, not loose.

Just tired of cleaning oil off the covers constantly.

Any suggestions, thanks.

[JeffMcKC]

Re: Valve cover breather/PVC question

I am not seeing the pcv is it in the intake ??? I thought the one on the Pass side when to the air cleaner and the driver side had the push in pcv in the top of it not both vented, if the one on the driver side is going to the vac sorce its a big leak. Its 5:00 AM maybe I my eyes are still closed.

[cstmwgn]

Re: Valve cover breather/PVC question

On my engines, I run a hose from the driver's side valve cover (breather) to the air cleaner base and a hose from the passenger's side valve cover (PCV) to the intake manifold (just below the carb). For carbs that have a 3/8" hose barb in the baseplate that is open to manifold vacuum that is also good. I use this setup with my stock valve covers on my truck and my BTs on the wagon.

[Eliteman76]

Re: Valve cover breather/PVC question

Jeff-
Here is another picture I took the other night with a different top on my air cleaner.


On the first picture, with the stock lid, there is that orange filter element that feeds from the passenger rear side into the air cleaner.
Here is another shot:

The driver side feeds from the large breather on the front, into a port on the base of my Edelbrock performer carb.
I have tried the idea of taking a small amount of degreaser, cleaned the breather and the seal, and it goes together great, doesn't shift around.
I just get that freaking oil mist.

Probably need to stop shifting my street car at every red light like I am trying to run the local 8th mile.

[cstmwgn]

Re: Valve cover breather/PVC question

Andrew

Have you tried putting the PCV valve to the manifold vacuum instead of the air cleaner?

[Eliteman76]

Re: Valve cover breather/PVC question

To be honest, no.
I was copying the original setup that the factory carbs use. They run a line off the driver side fill, to the base of the carb. On the motorcraft/autolite 2 barrel stuff I have had in the past, the port goes into the back of the carb.

Well also thinking about this, here is the thing, the rear line does not have a PVC valve in it, just a straight vent to the air cleaner. On the early 70's stuff {my 1979 F150 with a 400 is the same way} the rear line is just a vent tube, no PVC valve.
The driver side on the cleveland / modified engines had the PVC stuck right in the center of the oil filter cap.

I think that is the reason for the little replaceable filter on the inside of the air cleaner.

I wonder now if the large breather should be in the passenger valve cover?
Looks like I am actually going to have to dig out my early 70's emissions manuals.

[antmnte]

Re: Valve cover breather/PVC question

I have this same problem but I was under the impression that it didnt matter what side the pcv or breather was on.
I get that mist too I think its blowby but I could be wrong my motor isnt worn out either. I got valve covers with better baffles that helped it a lot.

[JeffMcKC]

Re: Valve cover breather/PVC question

The PVC has to go to intake vaccum and I still don't see a PVC. The little filter in the air cleaner is to filter air drawn into the crankcase then it comes out the other side breather with a PCV in it and is sucked into the carb base or intake manifold for mainfold vaccum. Right now you have not got a PVC, you just have a vented to atmosphere system

[Scott Liggett]

Re: Valve cover breather/PVC question

You want the pcv getting pulled from manifold vacuum. You can connect the breather hose to the air cleaner. I think my friends 302 has the pcv in the intake behind the carb.

I've had oil mist around my grommets on the pcv and breather since day one. Not a lot but a bit. Valve covers with baffles make a huge difference. I guess it's the price of having pretty parts that you have to keep cleaning them.

[antmnte]

Re: Valve cover breather/PVC question

When I had the valve covers with different baffles it made a huge mess. My PCV is going to manifold vacuum,still
get the mist.I guess its not blowby then?

[JeffMcKC]

Re: Valve cover breather/PVC question

When the intake Vacuum is high the PVC does not "Bleed" much vacuum it shuts off to help it control idle speed and mixture issues. All PVC do not "Bleed" equal amounts of vacuum and at the same inch closing point, it can be tailored to the combination to acheave what is needed.

So think about the amount of crank case pressure generated when the PVC is closed and are you drawing the right amount of vacuum against the spring to get the balance the PVC requires to operate.

[CarPlayLB]

Re: Valve cover breather/PVC question

When the intake Vacuum is high the PVC does not "Bleed" much vacuum it shuts off to help it control idle speed and mixture issues. All PVC do not "Bleed" equal amounts of vacuum and at the same inch closing point, it can be tailored to the combination to acheave what is needed.

So think about the amount of crank case pressure generated when the PVC is closed and are you drawing the right amount of vacuum against the spring to get the balance the PVC requires to operate.

How does one tailor a PCV to the engine? I get about 10-11 inches at idle with my combo. I tried a PCV system to keep my pretty valve covers clean, and it was just a giant vacuum leak! I would love to get rid of my open breathers and get PCV...how do I do that?

[JeffMcKC]

Re: Valve cover breather/PVC question

You could go down to a small four cylinder one, a old Pinto one is what I used for my old 302's. The older 4 cylinder cars made less mainfold vacuum ( like a V8 with a bigger camshaft) so the balance worked.

After building a Vac system for the 2007 Drag Week engine with a electric pump and a catch/ breather can That is the easy way to keep oil out of the intake also and keep detonation down too

[200WINS]

Re: Valve cover breather/PVC question

Andrew, Billet Specialties makes a real nice pcv valve incororated into a breather that will mount to the grommet on your valve cover. This kind of PCV valve is raised up out of oil splash. I use these on valve covers with no baffles. The pcv valve needs to go to a manifold vacuum source. The vent side can either be run through the filtered side of your air cleaner or perhaps a K&N style vent can be installed into the opposite side.
GM came out with a fixed orfice PCV valve for the 5.3 to control oil consumption, maybe another consideration.

[SpiderGearsMan]

Re: Valve cover breather/PVC question

pcv valves don't flow enough
road draft it !!! the fe had the breather in the perfect spot