oil buildup / leaking out of valve cover breather

[Topsterguy]

This is driving me CRAZY!  I've got a PCV on the drivers side valve cover at the back and a plug in breather on the pass side at the back. The bung for the breather has a built in baffle in it. The breather keeps getting oil in it and with higher RPM's the oil is leaking out, dripping down on to the header, and causing fumes etc in the car - not to mention oil on the firewall etc! This is a fresh 383 SBC  built be a very reputable builder with everything new, including the PCV. I checked the PCV and it blows thru fine and the hose isn't collapsing. Should I maybe T the hose from the base of the carb and run a PCV to the pass side too? This is weird, and driving home from a run last weekend I wound up wrapping a rolled piece of paper towel around the base of the breather to contain the oil leakeing! HELP!!!! :x

[HotRodLadyCrusr]

I know I'm only a girl and don't know much BUT aren't the value covers suppose to have the baffles in them?  I know mine do.

[Normspeed]

I imagine the air is supposed to flow into the breather, through the motor, out the PCV and into vacuum port on the intake. It does sound kinda like a baffle problem. I imagine teeing the hose and installing another PCV valve might cure the problem, but then where would it suck fresh air in? When the motor is running and the breather removed, do you get a suction effect at the breather hole?
Just my 2 cents worth...

[Topsterguy]

I know I'm only a girl and don't know much BUT aren't the value covers suppose to have the baffles in them?  I know mine do.

Hi Denise! Yeah, most of the time they do but it bothers me having a plate screwed in thereand there's always the chance something might fall out??? It looks like that's what I'll have to do tho. Thanks! Hey, ladies know lots too!

[enjenjo]

Mr Gasket has a baffled PCV grommet if it's the right size.

Also, check the PCV valve to see that it's the right one, if it needs too much vacuum to open, it may not be working most of the time.

[shine]

you are building more crankcase pressure than the pvc can handle. remember big cam motors don't build much vacuum. how old is the motor? molly rings ? you may have to wait for the rings to seat. pvc valve can not do it alone. the breather is to help relieve pressure. i run the moon breathers on my cars. they are larger and don't blow oil as bad. good luck.

[Bruce Dorsi]

I've got a PCV on the drivers side valve cover at the back and a plug in breather on the pass side at the back.
...The breather keeps getting oil in it and with higher RPM's the oil is leaking out ...

If the engine is mounted with a tilt toward the rear, you may want to switch your valve covers side-to-side, so the breather and PCV valve are toward the FRONT of the engine.  

The reason I suggest this, is that with the engine tilted toward the rear, oil WILL pool up under the valve covers near the back of the engine.  ....Acceleration, and/or higher rpm's will increase the likelihood of oil being sucked out.

Some vehicles mount the engine at an even steeper tilt toward the rear to gain clearance at the firewall or toe/floor board.   .....This, also, magnifies the problem.

Another possibility is to change your breather to the type that has a hose bib on it, and it's also a "push-in" style.   ....(I believe these were a Mopar design, but they are available from Mr. Gasket, and others.)   .....A hose is then attached from the breather to the air cleaner (inside the element) assy.  ....I realize that some styles of air cleaners prevent this suggestion.    

This type of breather system allows filtered air to enter the engine through the breather, and exit through the pcv valve, while the pcv valve is open.  ....When the pcv valve is closed, crankcase pressure and oil vapors will be drawn to the low-pressure area at the carb inlet.   ....Your engine will stay much cleaner, and oil should not drip onto the headers.

[tomslik]

the breather is to help relieve pressure. .

that part's not exaxtly correct.
the breather is to let air in otherwise you'll suck gaskets in and create an oil leak

2 pcv's and no vent WILL create MORE problems...

[Crosley.In.AZ]

2 pcv's and no vent WILL create MORE problems...

yep....... seen it on some cars. The motors I looked  at actually would whistle while running due to vacuum inside the crank case.

Shut the motor off and the whistle would fade away in a few seconds

[EMSjunkie]

I agree with Bruce, try swapping your valve covers
so the breather and pcv are up front.
ran into the same problem on a circle track motor.

swapped the covers and the leak stopped.  

just my 2 cents.

Vance

[Topsterguy]

As always, thanks a bunch, Folks!

[Topsterguy]

the breather is to help relieve pressure. .

that part's not exaxtly correct.
the breather is to let air in otherwise you'll suck gaskets in and create an oil leak

2 pcv's and no vent WILL create MORE problems...

How about 2 PCV's and two breathers?

[tomslik]

the breather is to help relieve pressure. .

that part's not exaxtly correct.
the breather is to let air in otherwise you'll suck gaskets in and create an oil leak

2 pcv's and no vent WILL create MORE problems...

How about 2 PCV's and two breathers?

well, it'll work but i'm thinking that you've got other problems.
better get a leakdown test done on it....

[jaybee]

How about 2 PCV's and two breathers?

I'd expect that setup to draw too much air through the PCV system and effectively be a vacuum leak.

[41woodie]

I had the same problem with a 350 running a worn out quadrajet, I swapped to a rebuilt quadrajet which was junk, then bit the bullet and bought a new performer and intake.  Problem over, the cause was low vacuum, the new carb didn't leak and solved the prob