Transmission and PCV vacum setup

[Georgelas]

My 74 bronco has an edelbrock performer intake with a 600 cfm Holley carb. I am trying to figure out the vacum system, it seems the blow by is not being pulled into the manifold. Small amount of blowby coming out of both valve cover openings. My understanding of the system is that the PCV hose is supposed to run into the carborator at or around the riser plate. the only hose nipple on the base of the carb is connected to the transmision (which i believe provides vacum to the transmission) to add insult to the situation it seems there is no pcv valve at all. There is a hose connected to the base of the oil fill cap on the passenger side valve cover that is connected to the air cleaner On the driver side is just an air filter connected to the valve cover. see pictures below.

1. where can I connect the PVC valve, (ordering one now).
2. does the transmission need to be connected to the carborator? Can it be connected to one of the plugged manifold inlets. If connected to manifold what type of connection? does it need a valve.



Thank you for any input you may be able to provide.

 

[Georgelas]

smaller picture

Sorry for the giant picture. Hope this helps.

 

[70_Steve]

Thanks! For me, resizing the pic helps me grasp what I was looking at!

The PCV (Positive Crankcase Ventilation) brings fresh air into one valve cover (usually the drivers side). That fresh air sweeps through the crankcase and is sucked out the PCV valve (usually on the passenger side rear valve cover)which is connected to the carburator base. The reason for connecting to the carburator base is so the crancase vapors get "evenly" distributed to all cylinders. The fresh air source could be a filtered breather or a connection to the air filter housing.

I see what looks like a vacuum line connected to the middle intake runner behind the carb with a newish looking brass fitting. Possibly for power brake booster? The C4 needs manifold vacuum, so you could just tee the two vacuum lines together at that connection. That frees up the carburator connection for your PCV valve.

 

[Georgelas]

Thank You

Thank You Steve. Yes the manifold is connected to the power brake booster. What if I add a port to the manifold? it has a number of plugs near by. I am concerned that my brake booster may be affected. Its already weak, I am running 35 inch tires. Could this affect the brake booster? Or is it all the same vacume system?

thanks again.

 

[70_Steve]

Thank You Steve. Yes the manifold is connected to the power brake booster. What if I add a port to the manifold? it has a number of plugs near by. I am concerned that my brake booster may be affected. Its already weak, I am running 35 inch tires. Could this affect the brake booster? Or is it all the same vacume system?

thanks again.

There is no air flow from the C4. It's just a diaphram, so your brake booster operation should not be affected. The bigger affect would be from the 35's. I had the same situation, and resolved it by going hydroboost.

 

[Georgelas]

Will this work?

http://www.summitracing.com/parts/sum-440308/media/images

I do not have a PCV valve. It is wide open and I don't want to run without a valve.

 

[70_Steve]

Will this work?

http://www.summitracing.com/parts/sum-440308/media/images

I do not have a PCV valve. It is wide open and I don't want to run without a valve.

Can't tell you if that will work or not. There's no application data for that valve. Not all PCV valves are created equal. Different flow rates, different checkvalve spring rates, etc. Plus, Holy Crap!!! $20 for a PCV valve??? Do you really need billet?

More important would be "Do your valve covers have a provision for a PCV valve?"

How 'bout a full frontal pic of the engine? Or a pic of each side, to get a little detail?

 

[Georgelas]

Ok so I should order a stock check valve. the valve covers provisions on both sides for a check valve and breather. See picks and thanks.

 

[70_Steve]

Ok so I should order a stock check valve. the valve covers provisions on both sides for a check valve and breather. See picks and thanks.

Unless you like the bling, I'd go with the stock PCV valve.

Not sure about "provisions on both sides..." What I see is a breather on the drivers side, and an oil filler cap on the passenger side with what looks like a piece of tubing coming out of the side.

If that's what's really there, then what I'd suggest is swapping valve covers side for side. Put the oil fill with that extra hose on the drivers side, and the breather on the passengers side. Then, replace the breather with the PCV valve and appropriate grommet, and hook the extra hose on the oil fill to a connection inside the air filter as a clean air source.

 

[gr8scott]

Is there a port on the backside of that carb for a vacuum tree?

http://www.steigerperformance.com/dif.cgi?sp01011

 

[red hot71]

Are there PCV valves that work on there sides? I'am asking because I'am in the same place and this is good timing.