Can this breather be used open

[KillerBee]

Can this breather be used without connecting a hose to it on my 440?
This is the first time I've used this type of breather.

I have a PCV valve in the other valve cover.

I just took the car out for a long test drive with the breather installed and didn't get any oil coming out of the top of it.

Will it work without blowing oil everywhere?

[GoodysGotaCuda]

That will actually be sucking air on that side of the engine. The PCV system will suck air through the opposite side valve cover, into the engine. In order for the oil seals not to be sucked in [from vacuum building in the crankcase] the other valve cover is vented to atmospheric pressure. Typically that style of breather will go to the air cleaner and feed off of filtered air, so that dirt/debris does not get sucked into the crankcase.

In summary, I would suggest a filter-style breather on that side, or plumb that breather to the air filter.

[mopar jack]

that breather should have a wire mesh inside that acts to coalesce oil vapor to drops allowing the oil to stay in the valve cover. You will want to run a  hose to the air filter to pull in fresh filtered air. Also under hard acceleration the pvc will see very little vacuum and if the engine is old with a lot of windage may go slightly positive pressure and oil vapors will go out the hose end to the carberator.

[73_Cuda_4_Me]

I believe that PCV diagram has the valve characteristics labeled incorrectly!

At low RPM or no-load cruise speed, you have high vacuum at carb PCV port, pulling valve open more against the spring (high flow).

At higher load or heavy acceleration, vacuum goes down, and PCV closes from spring pressure (low or no flow)...

The breather side flows some of the engine fumes into breather just opposite... high RPM = high air volume needed, so more 'suction' (not much, but enough to pull air) at breather port going into air cleaner. Anytime engine is running, a portion of the air is drawn thru breather into air filter housing, to lower emissions by burning the internal engine vapors (but idle has small flow requirement, so is the primary reason for pcv valve at idle - engine fumes run a little richer at idle from inefficiency).

On my 340, the valve cover breather feeds to the outside rim of air cleaner assembly - unfiltered air side, not filtered air side... the engine is pulling air into air cleaner snorkel and breather at same negative pressure from engine sucking air (except at low RPM and part throttle cruise, when there is low negative pressure in air cleaner but high vacuum on intake because of throttle plates, so PCV clears the fumes then).

On old engines, blowback through block was just vented to atmosphere through breather, and some oil/gas fumes always came out (slimy dirty valve covers under breather were pretty abundant back in the day before we figured out what we were doing to the atmosphere...

 

[HP_Cuda]

I believe they are telling you to have a setup that looks like this.

[73_Cuda_4_Me]

 

Why, Thanks, HP_Cuda! I'll take it... 1st dibs on the big block!

Want the address to ship it to...??

 

[KillerBee]

So is my current style push in breather OK?
It seemed to have worked good for the last 5 years.

[HP_Cuda]

Sorry it magically only fits in one Cuda. 

Why, Thanks, HP_Cuda! I'll take it... 1st dibs on the big block!

Want the address to ship it to...??

 

[73_Cuda_4_Me]

@HP_Cuda:

 

@KillerBee:

Should have vent holes in bottom side of that one under the lip... so would be okay (should be the mesh in there mentioned above to keep drippage minimal)

[YellowThumper]

Breathers that are just that will have more mesh inside to limit the oil from seeping or blowing out. The pic immediately above will have all the "breather" holes hidden on the bottom plate. Cleaner look than the corrugated one.

The one you have shown is designed to connect to the carb filter. It will have minimal mesh to control oil flow. Mist likely it only has baffling inside.

Change it for a designated breather.
If you get blow by oil then either hook up the hose one to your air filter or there is also an option to where it can be plumbed directly to the exhaust pipe. Weld a tube and check valve to it at a 30 to 45 deg angle and your exhaust flow will act as a siphon.

[73_Cuda_4_Me]

With a PCV on other side, 90% of the time the PCV will be drawing some outside air into engine through the breather, so shouldn't have hardly any residue coming out, as seems to be the case for the past 5 years...

Without the PCV it gets a little messy, like the old-time engines used to get...