Just one added thought.  After several years of running a PCV system on a stock motor, I moved it to a larger motor with a high flow oil pump.  The duck bill style baffle I had on the valley pan (PCV side) didn't control the oil splash off the dist. gear, and I picked up enough oil to send the engine into detonation and blew the left side head gasket twice.  I welded  a better baffle under the valley pan, and have not had the problem since, so I think that was it.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

After a little thought,I must agree with all of you about the lack of flow volume.For now I think I'll just re-install the draft tube and leave the PCV as is.Maybe the two together will stop the slight drip I used to get from the tube.This winter I'll figure out a proper solution.It's too hot now for strenuous brain activity.

Thanks for all the help.

 

Paul,

Boonville,MO

I think Holun put a little more modern PCV on his set-up at one time. The breather port cap at the front of the engine (where we are running the open style) is closed and piped to the air cleaner. If the engine doesn't get enough vent from the vacuum port - it feeds it down the venturi.

Could be thats the only way we'll get a completely clean system. 

 
 Steve Metzger       Tucson, Arizona

I have been following this thread as I have the same problem with my engine. I put the PCV on in place of the road draft to hopefully cure the dribble of oil from the breather on to the valve cover. It helped but I do still get oil dripping on the front of the VC. I am using the 5/16" port on the base plate of the Demon to a PCV that I mounted in the stock valley with a plastic elbow. Just wanted to add this due to the conversation about PSI v. flow.

I agree with you guys, after looking at my intakes, I don't think that this is a good place for a PVC valve. Those ports are just too small, could they be opened up some without affecting the flow on the rear runners, don't know, but I think that a carb spacer with the proper sized nipple might be a better solution.

Glen Henderson



Freedom is not Free

Letohatchee, AL

Basicly you shouldn't be able to blow through it in the direction of the crankcase. As I learned the hard way! Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

I've been thinking the same thing as John - you guys are putting vacuum on there - but no flow capacity. Look at the size of the PCV port on the Holley 4160 carbs - must be 5/16 - 3/8 opening? You end up compensating for this big hole with your idle and fuel jetng too.

The PCV valve is a reverse "check valve" that prevents pressurizing the crankcase with a backfire (at least that's what I was taught). 

 
 Steve Metzger       Tucson, Arizona

Those little holes could be closed down to very small holes and still give a vacuum reading, but would not flow enough volume of air to scavenge the crankcase.  

John

John - "The Hoosier Hurricane"

I have not physically checked the holes(incidentally this is a 4 barrel B intake),but I just put a vacuum guage on the port I'm using.It shows 19 inches at idle and recovers to that point after revving up.I am tempted to run this car without the valve,that is just run the vacuum line from the intake directly to the valley pan.Anyone know what will happen in this case?????

 

Paul,

Boonville,MO

pcmenten brought up a good point and it got me too thinking, so I just got back from the barn digging out my stash of B intakes. The setup that I am using is on a two barrel intake and is in the stock location and works great, but the B intake does not have the port in the top of the intake like the two barrel intake does. I looked at three different B intakes and all three off them had the two little holes in the rear. They all had at least one of the holes plugged up with carbon. I then pulled a B intake that I have had hot tanked for a engine that I am getting ready to build and while the holes looked open from the outside, when I ran a welding rod down them I knocked out carbon. They are not very big and could be plugged. Also as he suggested the fitting that you used could very easily be blocking the ports.

Glen Henderson



Freedom is not Free

Letohatchee, AL