Technical Sbc pcv system

This has probably been discussed numerous times but I haven't been able to find an answer for my specific question. I have a pcv system on my sbc, with a breather on the passengers side and a pcv valve on the drivers side hooked up to the carb.

Question: Can I put the the pcv valve and the breather on opposite valve covers, but both on the back side of the motor? This would put them directly across from each other, instead of the typical opposite end configuration.

Thanks in advance.




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Yes

 

Not only yes but preferably the PCV valve on the pass side. At least that's the way it was explained to me by a fella from GMPP and the way that I normally try to run mine.

 

That's the ideal way to do it. Mine is that way, except the PCV valve is on the front driver's side and the breather on the rear driver's side is epoxied shut.

NOTE: I misread the OP's configuration. It's best to have one in front and one in back for cross flow in the crankcase.

 

I've done lot of research on this over the years and set up a lot of pcv systems. I've never heard that. What would be the reason for installing it on one side versus the other?

 

DCR (direction of crank rotation)

 

The object of a "positive crankcase valve" (PCV) Is just as the name applies, to provide positive ventilation for the crankcase and/or engine.
Since the proper flow of air through the engine depends on the placement of the "vent" and the PCV I would think the the vent should be at the front of the engine, where-as the PCV should be to the rear on the other side of the engine..
The earlier SBC's, and for that matter, other engines had the "vent" via the oil fill pipe. Some engines had two "vents", one via the oil fill pipe and one via a hose in the valve cover running to the carb air cleaner..
As a general rule, aftermarket valve covers will be configured so that the vent is on the left front, the PCV on the right rear..
For my money I don't care for the older style billet vents that attach to the side of the valve cover.. They tend to look neat, however, I would be suspect of how much volume of air they can handle. Bill

 

Can't you interchange them?...........meaning configuration is at the installer's option.

 

All the PCV system does is allow for the relief of pressure caused from the crank rotation and to get rid of moisture. There may be some "oil vapor" or whatever that seeps past the rings, but mostly it's water you want to get out.

Now if the vacuum source and crankcase opening are oppsite each other then you could argue that is the best method. The internal gasses will seek the least path of resistance, so the location is not (IMO) all that important.

 

I don't like using the term "vent" when discussing PCV systems. You want the inlet (usually the oil fill tube on old engines) A PCV system creates a positive air flow through the engine the air enters the engine and passes through carrying the water vapor out through the PCV valve. The farther apart...the better. There are plenty of posts on this if you do a search. It's not just a vent!!

 

So I'm seeing some mixed responses. However, it makes sense to me the gasses will take the path of least resistance. I don't disagree having them opposite of each other would be more efficient. I just wanted to see what some other thoughts were.

Thanks for the responses so far .


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check outside edges of your valve covers closely. my chrome steel stamped covers are notched to clear the intake manifold to make sure that they tighten down tightly. so, the baffled breather holes must end up at opposite ends of motor.

 

So if I have the fill tube with the PCV fitting and hook the PCV valve to that and run a hose from there to the carb.
Running valve covers with no breathers.
later model SBC with no Road draft provisions.
I'm thinking I'll need to drill a hole in the back of the intake and run a hose from there to a remote breather? To have a fresh air inlet.
Or?
-Pat

 

Sometimes, you just have to Wikipedia stuff. It works, IF you work it. AND, it does NOT matter which valve cover it's in.

http://en.wikipedia.org/wiki/Crankcase_ventilation_system

 

My gut feeling is that it's not going to make much difference having them both at the rear of the engine, as opposed to diagonally opposite.

There is so much going on inside the crank-case when the engine is running that the air you are pulling out one valve cover has probably bounced around a lot since it came in from the other side.