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By 55Birdman - 17 Years Ago
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I have 292 with 3x2s edlebrock 573 intake. Downdraft tube wont fit in place. I want to install PVC valve. Where do I vent it to? I dont want to cut hole in valve cover and ther isnt a place to connect it to the carb. So, I need help. What can I do? Is there an alternative to PVC?
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By paul2748 - 17 Years Ago
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I have essentially the same setup in my 54 Ford. What I did for a PCV was make a spacer for all three carbs. For the middle carb, I drilled for a slip on hose fitting in the front (right angle fitting) and then angled drilled into both holes of the spacer. The spacers are 1 inch tall made of aluminum, but I could have made it about 3/4 of an inch.
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By 55Birdman - 17 Years Ago
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If I use spacers my hood wont close with the air cleaners on them. I am not wanting to modify the hood.
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By pegleg - 17 Years Ago
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The PVC valve can usually be mounted in the back of the valley pan, where the road draft tube mounts on later valley covers. If you have a vacuum port in the intake for the distributor or power brakes, tee it into that. Use an oil fill cap with a filter, or add vents to the rocker covers, or both. I think the big issue for you would be having enough room around the back of your intake to get to the valley cover. There are 90 degree valves available to route te hose away from your manifold.
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By 55Birdman - 17 Years Ago
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It is a tight fit all right . I am installing some 113 heads,270 cam,lifters,vintage speed valley pan when my neighbor gets his building put up. I have a set of chrome valve covers with breathers to install . I will have to take it all apart then so I am set . Just need to do a temp fix now. I will work on a 90 degree valve and try that first. BTW Frank I sent moz distributor yesterday to you.
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By mr4speedford - 17 Years Ago
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Ok, don't mean to hi-jack but thought I'd ask about a setup I've been thinking about.
I want to add a PCV by placing one under the intake, using the valley pan with a PCV sealed in it. I would seal off the road draft canister, and use a filtered cap on the oil fill. The valley pan would need a small baffle under to prevent sucking oil(like the the later factory pcv valleys. The question is where to route the other end of the pcv? I don't want to go into the air cleaner.Am I way off on the thinking here?
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By oldcarmark - 17 Years Ago
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You could drill and tap a hole in the intake or find a spacer plate off later model with the port in it for PCV hose.I don't know if you have a 2bbl or 4bbl.As far as modifying valley cover they are fairly plentiful already done for PCV.Maybe this answer helps?
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By mr4speedford - 17 Years Ago
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I think I'll tap the back of the intake. Having never messed with any PCV'd I was afraid of it acting like a vacuum leak, but I did some reading and I see I was wrong. Thanks for help.
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By oldcarmark - 17 Years Ago
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If you are going to drill and tap you need to be close to the centre of manifold as close to carb as possible.If you go into end of manifold it will create lean mixture on rear cylinders.If you do drill and tap there is a screw-in PCV valve you can use if you do the correct size and thread.If you have a 2bbl 4 bolt mounting you should be able to use a mid 60's spacer plate with PCV port in it.Apparently you can also place PCV valve in rocker cover best between rocker arms over one of the supports. There are several posts on this if you search previous items by entering "PCV install" as a search.I just did my 56 using a valley cover I got off 55Birdman.Works great!Use a 1 1/4" cup type freeze plug to cover hole in block when you remove draft tube.Held in place by bolts used on draft tube.Hope this helps,Mark
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By Duck - 17 Years Ago
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For what it's worth, I bought a pair of baffled pcv grommets from Summit for a project I was working on. They're a TransDapt item... /Duck
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By charliemccraney - 17 Years Ago
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I would not use the baffled grommets. I used some and they significantly reduced the ability of the breathers to breathe. You will be better off welding, perhaps even JB welding, a real baffle in place.
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By pegleg - 17 Years Ago
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Do what Charlie said, Screw or glue a baffle that seperates oil from air on the bottom of the valley. I made one from sheet metal for mine. Just make the air reverse direction and give the oil a way to drain out.
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By Ted - 17 Years Ago
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mr4speedford (10/21/2008)
The question is where to route the other end of the pcv? I don't want to go into the air cleaner. Am I way off on the thinking here?Where one side of the PCV valve goes into the crankcase (valley pan in your case), the other end goes to a direct vacuum port either at the bottom of the carburetor under the throttle blades or a carb spacer or by using the direct vacuum port in the intake manifold. Mark is absolutely right in that the closer that the direct vacuum port in the intake manifold is to the carburetor(s), then the better.
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By 55Birdman - 17 Years Ago
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My valley pan has a baffle on it.I think you guys have dropped MY question and started answering the OTHER question. My downdraft wont fit anymore due to the intake When I drive the car it blows out the hole like whale. I need to stop that. I am thinking PVC valve. But I cant install spacers because my hood wont close. I need a temp fix for a few months till I can begin rebuilding the engine. The downdraft tube simply vents the exhaust gases down and out of the engine near the starter. Can I install a 90 degree PVC and a tube send the exhaust gases down by the starter as it is now? MY QUESTION ONLY PLEASE
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By charliemccraney - 17 Years Ago
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Surely someone must have the 573 with road draft. My solution would be to find a spare road draft tube, a bfh, and make it fit.
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By Hoosier Hurricane - 17 Years Ago
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Birdman: If Charlie's plan doesn't work, some kind of 90 degree fitting might work, but you don't want it to be a pcv valve. A pcv needs a vacuum connection. Just a thought, but might a copper pipe or pcv plastic 90 degree elbow work somehow? You could even use a rubber/vinyl hose for the downdraft, just keep it off the exhaust pipe. Maybe a visit to a home improvement store is in order. There were two types of draft tubes. One has a round cannister-looking part that bolts to the valley pan and the draft tube is weldede into the side of that cannister. The other type looks like someone cut a straight tube off at 45 degrees, rotated the parts 180 degrees and welded them back together to form a sharp 90 degree bend. The first type needs more room than the later one. Which do you have? John in Selma, IN
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By oldcarmark - 17 Years Ago
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Hello Earl,Kinda got of topic there.Can you not drill and tap into manifold near centre carb same as was suggested to the other fellow?Put in a screw-in PCV valve and run a hose from an elbow and grommet where you have a hole now?Doesn't require a spacer at all.
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By GREENBIRD56 - 17 Years Ago
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OK - back to basics - what clearance exists between the old draft tube port and the bottom of the tri-carb manifold? Is it an inch? What do you have to work with? I don't have access to one of the manifolds to look at it. PCV valves provide several practical functions - (1) they provide a high vacuum source to ventilate the engine interior with a checkvalve to prevent backfires from pressurizing the engine case and (2) they also restrict the volume of air ingested into the intake so as not to complicate idle control at the carb. Is there room for a "cookie" (of whatever suitable material), an O-ring and a capscrew to hold it down? That would eliminate the draft tube exit on the valley (for good or for evil). It won't be the puke point anyway. The engine still has to vent. Over the years (many) - not necessarily the Y's - have vented via atmospheric breathers on the two valve covers. This may not be the way you prefer to do it - but two breathers on a couple of tin covers would let you run the motor while you work this out. There are caps for the top of the forward valley cover tube that are closed - have only a shiny top and a hose fitting out the side. Attaching this port to an elbow in the underside of the center carb air cleaner will put (some) vacuum on the vent. This system won't necessarily require a PCV valve - but (depending on engine condition) it may require a restriction to keep from heavily oiling the carb. Another idea - at lower left front on the side of the block is the old style draft beather port. Many are now capped. Intall a PCV valve at this point and run a vent hose up to an elbow on the bottom of the center air cleaner. Use a free flow pleated element cap for the forward valley tube. You want the engine to have ventilation sufficient to avoid pressurization - and oil loss control. Try a few things and see what you (and the engine) can live with.
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By 55Birdman - 17 Years Ago
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The back edge of the manifold comes over the hole in the valley pan just enough to prevent the tube from being installed or the intake from being installed. This is intake ___________ o= hole oooo just wont fit there is about an 1" clearance between intake and pan. intake comes over the hole about 1/2 inch or so. If anything will fit in the hole it will have to be at an angle. Which may be homemade as the best bet for now. I have breathers for the valve covers which I intend to install later but I may have to do that now.
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By mr4speedford - 17 Years Ago
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Ted, I will take your advise and use a carb plate, as I have the luxury of extra room. Thanks for the help.
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