If you size the pcv correctly, you will not have any measurable loss of manifold vacuum. The only way for the pcv to work properly is connected to manifold vacuum. Hook up a vacuum gauge to measure before and after pcv installation. Two areas that may need some sealing are the distributor housing and dip stick tube, to ensure maximum vacuum.
If you suck on a PCV you see that there is hardly any resistance to it allowing flow. But, it doesn't take but a whisper of breath into it and the thing slams shut. That's what they're designed to do, right? In the case of a backfire, the pressure slams the valve shut in order that crank case gases may not be ignited. So, I use that feeble bit of logic to ask why worry about leaks around my distributor or dipstick to optimize my vacuum? I choose to use the inlet side of my carb for a low pressure source versus adding a source of air that potentially leans out my air/fuel mixture downstream from the carb. I think that we have beat this horse enough. Both sides have presented ideas on how a PCV may be plumbed on a flathead. Those contemplating the installation of them may choose their own course.
Chipman,...your idea will work; I used a "freeze plug" where the old road draft tube was...brazed a fitting into the plug, and ran a hose to the pcv valve, threaded into the center of the intake manifold. 4TRUK
Ps; I used an existing vacuum port on the intake,...to prevent adding another hole in it. Happy Roddin' 4TTRUK
For further PCV reading enjoyment -- http://www.fordbarn.com/forum/showthread.php?t=64276&highlight=chrysler-style Jack E/NJ
Mine (see pix). The motor is actually an 8BA decked out to look like a 59A. I'm running an early style intake so I pulled the lifter valley tube and plumbed this under the manifold with a NAPA CRB29255 PCV valve that is designed to work horizontally (Borg Warner PCV255 designed for vertical but works horizontal. Fits 1990 V6 Isuzu trooper II (1993 Isuzu has nipple on both ends). 1965-66 Caddy 429 (California) uses a horizontal valve and calls for the PCV255). Clean and out of sight. The valve is pointed forward so it doesn't just suck the makeup air from the stock breather on the fuel pump stand. There was a discussion a while back about sucking too much oil if you hook the PCV directly to the 8BA oil fill pipe: http://www.jalopyjournal.com/forum/showthread.php?t=36438&highlight=adjust+clutc h
The best unsightly idea i have done is to remove the intake ,drill the bottom for a vacuum port ,install a short hose to the small end of the pcv.the large end of the pcv will be left open.plug the draft tube.leave your vent.No one will ever see it.
I mocked this up but never went with it due to the fact that the PCV is a controlled vacuum leak and all the air is added to one cylinder which will probably lean out that one cylinder. All factory PCVs that I have ever seen are at the base of the carb so that the added air will be distributed to all the cylinders instead of only one. Be careful that you don't lean out a single cylinder with were you locate the vacuum source.
Tommy, find an air cleaner that covers both carbs. Run your line from the PCV in the fuel pump stand up to a fitting in the base of the air cleaner. You will have to block off the base of the vent scoop and use it just as an oil filler cap. I assume you will use this on a 59A or earlier where the vent is on the oil pan. With that set up air can come in from the oil pan vent and exit to the air cleaner. It might not be necessary, but I would run the tube that goes from the fuel pump base into the block so that you're not sucking oil mist from the galley. Obviously, put plugs in the runner holes.
For the Caddy, just find the vents, inny and outy. Adapt from there using the ideas espoused in this thread.
We have a few different styles to match the three bolt intakes, such as the Stromberg 97 and Holley 94 standard base shapes. Also the Edmund's / Thickstun / Tattersfield shape. We do have the WW / Carter / and small Rochester 2G vacuum riser as well. If you don't see it let me know. Dashman's Hot Rod & Speed Parts www.dashman.net
Exactly the way I did it . you dont have to see it .. even distribution . Has worked flawlessly for 10 years.
I have a 53 flattie with a PCV installed in the road tube hole, the hose runs into a fitting tapped in the center of a edmonds 2x2 intake now i am under highway speed blowing oil out the filler tube instead of sucking clean air which leads to a cabin full of smoke. i am 67 and have a wwII gas mask i an contemplating using when i drive lol HELP
I am not running a PCV on my 8BA, I have a vented oil filer cap in the rear of the intake and a Offenhauser baffled vent in the oil pan. On the dyno that engine showed a little vapor form the lower breather but no smoke, no oil. Not my idea, Joe Abbin put it in his "bible" I just followed it chapter and verse.
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