Crank Case Ventilation Trouble

[FluoFerret]

What type of setup do you guys run for your crank-case ventilation, and what are your resonings behind it?

For the time being, my engine runs a breather on the passenger side valve cover and a pcv-valve on the driver side, going into a catch can and then into the base of the carburetor.
Trouble is: under light acceleration now, the engine hesitates with a deadspot until I release and accelerate again but harder. When the port at the carburetor base is closed down, the issue is gone, and the engine doesn't suck any extra air. The problem is: no more active ventilation.

My idea now is to just get rid of the breather on the passenger side and keep the rest in place. This should create a good vacuum in the crank-case to suck up any blow-by. Does this make sense, or am I running in the wrong direction here?

 

[DRIVEN]

Maybe try a different PCV.

Are you running an EGR?

 

[FluoFerret]

Maybe try a different PCV.

Are you running an EGR?

No EGR, and I already tested 4 pcv-valves from different manufacturers ^^ same effect.

 

[DRIVEN]

Okay. Breather size really should have no effect on a lean spot. Your system, as described, sounds just fine. You may just have a lazy accelerator pump.

 

[TURNA]

With 2 breathers does it do it??

 

[FluoFerret]

With 2 breathers does it do it??

just tried your idea with a spin around the block. fortunately i had another breather. with two of those and no pcv-valve, the problem is gone... that's quite odd...

 

[TURNA]

That will be $110 diagnosis fee!!!

 

[fleming442]

Doesn't the PCV go on the passenger side with the breather/inlet on the drivers? Or, is this right hand drive? I just confused myself, thanks!

 

[pagrunt]

I've got the PVC on the drivers side & breather tube on the passenger side. But it shouldn't matter as the '67 SBC had the PVC on the oil fill tube on the front of the intake.

 

[Bonnewagon]

no pcv-valve, the problem is gone

Because it is not sucking any air now. Originally cars had a road draft tube that relied on air turbulence to suck crankcase fumes. A better idea was to run a PCV valve that sucked a controlled amount through the carb via manifold vacuum yet not enough to be a vacuum leak. One breather in a valve cover drew in fresh air to displace the fumes. During low vacuum conditions the fumes exited the breather. Emissions later mandated the modern closed PCV system. The PCV valve still sucked a controlled amount during high vacuum, but at low vacuum the tube that goes from the valve cover to the air cleaner took over and sucked the fumes into the carb. Thus you had true full time Positive Crankcase Ventilation. When you ditch the tube to the air cleaner you upset the system. Now the valve cover breather acts like a vacuum leak, causing lean conditions. Older, richer, jetting could stand the extra air but our leaner emissions carbs cannot.