The Stovebolt Site Forums The Shop Area Engine Shop Vacuum brake booster & PCV question....

I'm going to be installing a power brake booster from ccp on my '59 Fleetside with a 235. I'll be running the vacuum line to the Edmunds 2 x 1 intake. Now I also want to run a PCV line, with valve installed inline, from my modified road draft tube to the same port (as theres only one on the manifold),
to suck the crankcase vapors back into the combustion chamber. Will this cause the booster to gum up because of sucking those (PCV) vapors into the canister? I guess I could filter them...and more important will pluging the PCV line in with the booster line cause a significant loss of vacuum so that the brake booster would not have enough vacuum to operate?

I believe it will lower the vacuum to the brakes.

Should work just fine. My truck came with the factory PCV setup. The vacuum line to the wiper motor and the line to the PCV connected to the same port on the intake manifold (a sort of a tee fitting). The wiper motor didn't get gummed up; air flow is from the wiper motor to the engine intake manifold.

I replaced the vacuum wiper motor with an electric one. The wiper motor manifold port is now used for the brake booster. Works fine.

Any other thoughts on this?

The brake vacuum hose, needs to be on a seperate fitting to the intake. Otherwise, you will lose full vacuum to the booster and it won't be much good to you.

OK, here's a picture of the fitting I was talking about. Good enough for the factory - good enough for me.

[img]http://members.shaw.ca/ghillsden/misc/fitting.jpg[/img]

Not sure what type of booster you are using. The old "HydroVac' unit I got had an external inline check valve "to install a minimum of eight inches above the vacuum inlet" to prevent back siphoning of oily gasses into the cannister. Most modern boosters I've seen have a check valve mounted right to the front of them, where you slip the hose onto the fitting.
From what I understand most boosters operate with about 9" of vacuum. Your relatively healthy motor should be producing 16"-21". IMHO you'll be just fine.

I'm trying to set up a PCV valve from the draft tube to my Offy dual intake and at the same time use a dual action fuel pump (with aux. vac. pump) and power brakes.

What I'm planning on doing is running the PCV through a filter (The Condensator) to the intake through a tee. The other half of the tee will go to a vaccum canister I'm getting from the bone yard. The vaccum from the auxiarly portion of the fuel pump will also run to the canister and then from the canister I'll run a line to the brake booster. That way, I hope, I'll have plenty of vaccum to charge the booster and keep it charged.

As I understand it you need 18" of vaccum to charge and use the booster. With a 3/4 cam at higher revs you have less vaccum that you would with a stock cam. I don't want my brakes to fail at high speeds/high revs, when I might really need them. Thats why I'm thinking about the cannister set up.

Any thoughts?