Yes I know. I have already read a lot of posts and threads relating to this PCV thing on flathead Fords, but have always walked away more confused with all the opinions, never knowing what was fact and what was fiction. Possibly not specific for this kind of engine configuration either... Anyways here goes, I am working out all my hookup points on my 346 Cadillac flathead engine which is running a Burrell 2 x 2 Rochester 2GC setup. I can hookup my PCV valve to the rear carby quite easily and run it down to a valley plate, which I hope is correct. What I need to know is where to get vacuum for my brake booster. My front carby has a vacuum hookup point similar to that of the rear carby, but does not run at idle and comes in progressively. Could I still get vacuum to run my brake booster from here??? Or, can I split my PCV line and use the same rear carby point to run a PCV and take vacuum???
Russ, why not hook the brakes to the rear carb, and PCV to the front? Since the engine never had a PCV originally, and the PCV isn't need much until off idle, I would think this would work fine.JMHO
Are you sure about that? That port is below the butterflies and therefore manifold vacuum. It's fine to T them together and come out of only one carb. You might loose some flow through the PCV valve when your foot is on the pedal momentarily but that will not cause your engine to sludge up. IMHO
Thanks Buddy & Tommy for your logical comments. I think I will try the split rear carby idea first up as it helps keep thing tidy, but if this turns out not to work any good I'll follow up with the other idea using both carby's. Many thanks and Happy New Year to you.
Well, I've done a little extra work on my PCV situation and by posting what I have done, I hope will gather some constructive input. I decided to use only the rear valley area to pull vacuum from, so I took out my rear valley plate and machined out the bung area designated for a PCV unit. I then installed the rubber and PCV unit as per the pic's. I then made a stainless steel tray that would fit snuggly into the valley opening and allow my valley plate to sitover and into the new tray. Using this tray method means I needed to double up on valley plate gaskets and use slightly longer bolts/screws to hold the new combination of tray and valley plate in position. A hole was then drilled into each corner of the tray to allow excess condensed oil vapour to run back into the engine. At this point I decided to utilise an old wire mesh screen I had removed from an oil bath air cleaner discussed in another thread of mine. http://www.jalopyjournal.com/forum/showthread.php?t=795932 The wire mesh screen is to minimise the chance of any of my stainless steel dish scrubber filter material from falling into the engine. Also salvaged from my oil bath air filter was a small circular gizmo that I decided would work as a kinder dam and help ensure no filter material could be drawn into my PCV unit. From there, I just place the 1st gasket into position, then place the tray over the 1st gasket and then add a 2nd gasket, followed by the valley plate. I am hoping this will be a reason method of providing me with a suitable PCV system for this flathead engine.
Thanks Buddy. Below is the link to the original valley plate thread for anybody that maybe interested... http://www.jalopyjournal.com/forum/showthread.php?t=372173
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