Please point me in the right direction. I searched several post but don't seem to get the answer. I have a 53 Flathead with a 1107 edelbrock intake and a holley carb. currently I have a PVC valve with a hose connected to the passenger side of the carb to the big port. in the line there is a plastic 1/2 turn valve that can close off the vacuum. I just installed a brake booster and put a TEE on that Big fitting to run it. why would there be a valve to shut off the vacuum to the PVC? should it be hooked up to that port or just vented?
Not sure about the valve but you do not want the brake booster hose hooked up to your PCV vacuum line. It needs to be hooked up to manifold vacuum only.
Saltflats is right. A pcv valve is a controlled vacuum leak and needs its own connection at or under the carb.
Sorry for the TYPO. I have no other place to connect the PCV valve. do they make an adaptor that has a vacuum port that I can put between the carb and manifold??
I wasnt trying to be a smart****, just trying to help....it was pvc in the****le and in the body of the post.....so 2 typos.....
The valve on the PCV hose may have been installed as a testing device, like "let's see if the engine runs differently if I shut the PCV down". Venting the PCV line will defeat the P in PCV. I looked up your manifold and saw stock pictures with a pre-drilled port at the plenum under the carb on the driver's side---- maybe yours has one that's plugged? If you want another vacuum port, it's pretty easy to drill and tap a hole in the manifold at the carb base, but I see no reason why you can't share the same port. Manifold vacuum is manifold vacuum. It all comes from the same place. Putting multiple ports doesn't change anything. The PCV valve is upstream from the vacuum flow and won't affect your booster in any way. I have my vacuum wipers on a shared port with my PCV. No problem.
I do not know what carb you have, but Ford made Ford (and maybe others) made spacer plates that go between the carb base and manifold that have a vacuum port that will work fine for your booster. i see no problem with putting a tee in the PCV line it has now. do away with the shut-off valve.***** is*****, no matter where(or who) it comes from.
I have a pcv set up on my 50 flatty with the Holley 4 barrel and I am not using a shut off valve. As mentioned above you do not want to run your brake booster off the same line as the pcv. You risk oil fumes, which through time will add up to oil, in your booster. That can't be a good combo. Drill a hole in the manifold, preferably just below the carb, for the booster line. Here is a pic of the big ol fat rubber line connecting to the carb and another pic of the opposite side of the engine showing the rubber line connecting to the pcv valve.
I drilled into the bottom side of the intake plenum and put a fitting for the PCV on my flathead and ran the PCV valve hidden under the intake in the valley
thank you all for the help. I see no hole, on my intake. we removed spacer/plenum and are going to drill and tap it this weekend. I really appreciate all the help. I did look for a carb spacer with a vacuum port but couldn't find one for a Holley 390, (4160). Mike51, I agree with your thought on the tester... I am going to eliminate it and move one. 56shoebox, LOVE THE PHOTOS!!! THANKS! our next task will be a SN60 !!!
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