Hi folks, I have a 350 with tall "Chevrolet" chrome GM valve covers. I have a breather/oil fill cap on one side and the pcv on the other which leads the middle front vacuum hose on my Edelbrock 600cfm carb. I noticed that I'm getting a lot of oil heading up through the pcv valve and in the hose leading to the carb. Also, the breather/oil fill cap's element on the other side is loaded with oil which is splatters all over my spark plug wires. Have any of you experienced this problem? What can I do to diagnose this? Do I even need them? Or can I do without one or both? I'm just afraid that oil is getting sucked into the carb. Any advice would be appreciated. Thanks, Malo

Do your valve covers have baffles in them? If not that's probably 90% your problem.

yeah baffle can be the problem
Also; how much milage your engine got? does it consumes oil?
Is your PCV functioning like it should?

Like others said.. Hows your valve cover baffles.. Does your covers have them, what type full boxes or just a single pc. of sheet metal?

Next is the engine stock or does it have alarger cam, more compression, etc?

I have not had the greatest luck with norm PCV valves on performance engines.. I have only found 2 that works well.. Replacement for the '69 camaro 302 , and the 4th gen F body 3.1 L (I think) v-6 pcv valve.

Yes you need a PCV valve on one side and a breather on the other side.

I would start with a leakdown test on the motor to see why it's pressurizing the crankcase. With any PCV at all it shouldn't be puking oil out the breather,, there should be vacuum on the breather.

With the motor warm pull the breather and see if it's puffing smoke. If it is pull the PCV and make sure it has vacuum and 'rattles' freely when you shake it. Like already mentioned, the baffles are a necessity and that needs to be corrected if they aren't there. But I ber there is more to this story.

Ditch the pvc and run 2 breathers. My valve covers dont have baffles.

you can't run a pvc valve and a breather. it would cause a vacuum leak. you would be sucking unmetered air through the valve cover into the crank case and then to the intake.

you can't run a pvc valve and a breather. it would cause a vacuum leak. you would be sucking unmetered air through the valve cover into the crank case and then to the intake.

Say WHAT??????

:confused:

Hi folks, I have a 350 with tall "Chevrolet" chrome GM valve covers. I have a breather/oil fill cap on one side and the pcv on the other which leads the middle front vacuum hose on my Edelbrock 600cfm carb.

I have the same valve covers with a PCV valve in the driver's side, and a breather in the other one. Those covers have baffles in them. Never had a problem with oil blowing out in the 17 years I've been driving it. You may have a ring sealing problem. Like Marv said- a leakdown test might tell you what's leaking.

Say WHAT??????

:confused:
^^^+1:confused:

Ditch the pvc and run 2 breathers. My valve covers dont have baffles.


I dont recomend that ^^.

PCV is a good thing!

you can't run a pvc valve and a breather. it would cause a vacuum leak. you would be sucking unmetered air through the valve cover into the crank case and then to the intake.


I have never in my life heard that one before. I have always ran a PCV in one cover and a breather in the other.

Heck GM pretty much did that stock on most of thier OE engines, they just couldnt have an un filtered breather stock due to EPA and emission std.

Could the oil drain holes in the heads be plugged? If so you could have excessive oil splashing around under the covers and affecting the pcv and breather. But first, like Marv said, check for vacuum at the pcv.

I have the same valve covers with a PCV valve in the driver's side, and a breather in the other one. Those covers have baffles in them. Never had a problem with oil blowing out in the 17 years I've been driving it. You may have a ring sealing problem. Like Marv said- a leakdown test might tell you what's leaking.

^^^ That's it... Excessive Engine Wear can cause it as well as faulty breather and bad baffle...

I'm having similar problems, and have a question about the grommets.

A the moment, both grommet are little more than sleeves, i.e. fully open.

In a spare engine I have, they are both semi-sealed, i.e. it's like and inverted cap, with a slot in the bottom that acts like a valve (looks like will only allow flow into the engine.

What is the proper setup? On the assumption that the breather is supposed to breath in, I guess on of the slotted ones, and with the PCV sucking out, it should be the open ones.

Im having the same problem . I had valve covers with no baffles. Thats a no no.

Theen i put just sheet metal as baffles, good but to eliminate any excess, i agree you need to box them.

Then i bought the right fitting breathers with the wings to fit right in the opening lips, but still im getting some trickles on my valve covers, and ultimatly dripping on my headers.

Want to put a PVC valve on a breather (or both) but I used the rear carb port for my brake booster.

Where else can i hook up a PVC valve?

I'm having similar problems, and have a question about the grommets.

A the moment, both grommet are little more than sleeves, i.e. fully open.

In a spare engine I have, they are both semi-sealed, i.e. it's like and inverted cap, with a slot in the bottom that acts like a valve (looks like will only allow flow into the engine.

What is the proper setup? On the assumption that the breather is supposed to breath in, I guess on of the slotted ones, and with the PCV sucking out, it should be the open ones.


I'm trying something myself now. What I did was take a grommet that was basically a plug, closed at the bottom. I took a razor knife and cut a cross in the bottom of the plug. So it will breath, but will, hopefully block oil from going on my valve covers, since my valve covers don't have baffles either.

i had leaking problems with the el cheapo Mr. Gasket breathers. i switched to a K&N breather and it all went away. the Mr. Gasket ones have a sponge in the top and it absorbs oil, then rots away, then leaks.

Me to

I have never in my life heard that one before. I have always ran a PCV in one cover and a breather in the other.

Heck GM pretty much did that stock on most of thier OE engines, they just couldnt have an un filtered breather stock due to EPA and emission std.

might need rings in it?