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Hot Rods Corvette WCFB difference ???

Discussion in 'The Hokey Ass Message Board' started by larry k, Mar 17, 2018.

  1. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

    trying to clone a set of WCFB carters on 1959 corvette 2x4 factory manifold . When I run both carbs at the same time I have a big ass vacuum leak through the front carb, close it off she runs fine ,put the front carb on the rear she runs fine. So both carbs are working well ,how did the early corvettes run both at same time without the same problem ? Tell me what the difference in my carb and the factory front carb is !!!
     
  2. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,799

    jimmy six
    ALLIANCE MEMBER

    I don't know your problem but the real front carb had no choke or the holes for any of it's parts. They were all progressive. I would check the base fitting to the manifold. Stock cars had a passage in the cast iron for heat. I don't know on the aluminum dual quad manifolds.
     
  3. are you running them progressive?
     
  4. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

    Yes the factory manifold has a passage for heat, and I am running progressive linkage. It has to something to do with the air flow. Shove some shop towels down the front carb to shut off most of the air , idles and runs fine !!!!! Some body has to know the answer to this ????
     

  5. jeepsterhemi
    Joined: Dec 5, 2009
    Posts: 12,581

    jeepsterhemi
    Member

    Here is what I got from Carter manual....

    20180317_154101_Burst01.jpg
    20180317_154144.jpg
     
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  6. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

    Well I sure ain't got much help on this, man some carb guys have to have the answer !!! Still waiting ,where are all the Carter guys at ?
     
  7. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,074

    greybeard360
    Member

    How about some pics of the manifold with carb off of it, the gaskets and base of the carb. Guys are guessing about the problem without seeing it first.

    Sent from my Moto G Play using The H.A.M.B. mobile app
     
  8. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,074

    greybeard360
    Member

  9. Deuces
    Joined: Nov 3, 2009
    Posts: 23,753

    Deuces

    We need pictures!!!!!;)
     
  10. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

  11. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

  12. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

    I removed the chokes from both carbs , I rebuilt both carbs , the carbs are working fine if only one is run on the engine at a time . I have a plate to cover the front carb mounting area so I can run the rear carb alone , it is the primary . I removed a set of 3x2 Rochester and replaced them with these, I had no problems with the trips they had the aftermarket bases on the end carbs .​
     
  13. upspirate
    Joined: Apr 15, 2012
    Posts: 2,299

    upspirate
    Member

    Tri-power front & rear plates seal when closed....maybe the front 4 bbl throttle plate is not sealing off? Just a guess on my part
     
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  14. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

    Yes that's right ! Now ,you guys are getting what I mean ! They are not sealing , so how do the vette front carbs seal ?they must have different lower base or different ,tighter,beveled ,bigger ,throttle plates they run 2 carbs at the same time? mine are pretty tight to the bore but you can see a little light around them when held to the light.
     
  15. sound like a vaccumm leak. maybe the intake?
     
  16. Andy
    Joined: Nov 17, 2002
    Posts: 5,117

    Andy
    Member

    Stock set up was progressive. Front carb would start to open at maybe 60%. Looks like you are using 57 pass carbs. They have larger barrels. You may have a sealing problem with the bases. Might look at the gaskets to see if they are sealing.
     
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  17. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    56sedandelivery
    Member Emeritus

    carbking, member here, has had a few things to say about these WCFB's, especially when used as replacements for true dual four carburetor applications; might send him a PM. Did your carburetors have the choke housing that mounted to the main body, or down low on the throttle body? The throttle body setup IS NOT the one to use when making "clone" carburetors, which is essentially what you're trying to do. I can't tell from your photos, the black paint is hiding things. I personally can't give you the exact reason why that is, and it's information I only recently heard myself. I went with clone carburetors from a vendor for my dual quad setup, the "early 56" Chevrolet 2 X 4 manifold, and unless you look at the "numbers", it's hard to tell they are "fakes"; all the no-used holes are plugged, vent tubes added, etc. My setup is't currently on an engine. My concerns were the secondary "weights" are quite a bit smaller on the dual four applications, but that apparently is't a real concern. My bet goes with carbking having the answer for you.
    I am Butch/56sedandelivery.
     
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  18. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

    I'll be callin the king on Monday , gotta get em both runnin at the same time! thanks for everybody's help. damn this place is coooool
     
  19. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,799

    jimmy six
    ALLIANCE MEMBER

    image.jpeg May be they just need a different engine... like an old Y-Block. I idle on both and run on the rear. I must floor the pedal when cold to squirt fuel to the front ports. They are same number 1953 Oldsmobiles off 303's small base.
     
    Last edited: Mar 18, 2018
  20. Danny G
    Joined: Aug 1, 2006
    Posts: 399

    Danny G
    Member

    I idle mine on both carbs and they work good
     
  21. How does the front carb get air down the throat but not take fuel too?
    both carbs have Idle circuits and both carbs work well in the rear position.
    Yet when either carb moves to the front position it stops delivering fuel and only adds air.

    Are you changing the idle mixture screws when you swap positions of the carbs?
     
  22. Andy
    Joined: Nov 17, 2002
    Posts: 5,117

    Andy
    Member

    Fuel line to front carb stopped up?
     
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  23. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    The throttle bodies on the genuine dual quad carbs differ from other throttle bodies. And the gaskets used are totally different.

    Before calling:

    (1) Place one of the carbs on top of a Xerox (oh, showing my age again.....copy) machine, and make an exact paper copy of the bottom of the flange. Carefully cut out the air/fuel holes and the mounting holes.

    (2) Place this "template" on the front carburetor "pad" of the manifold to check to see if it seals.

    (3) If it does seal, then visit your FLAPS and acquire some of the black rubberized gasket material 1/32 or so thick, and hand-cut 2 gaskets.

    (4) If it does not seal, you will need an adapter.

    EDIT: Had to do some chores before finishing post.

    What displacement engine do you have this on?

    283 - use progressive linkage
    327 stock - use progressive linkage
    327 w/hot mods - use solid linkage
    350 - use solid linkage

    Glad to see you have been testing. Your tests basically show an incompatibility of the larger throttle body and the front pad. If there are no issues with the intake, then the custom gaskets (or adapter) should solve the issue; and even though the rear carb is not leaking, the second gasket is for the rear. Gasket deterioration might cause it to leak in the future. Do it once, do it right......the mantra of those of us too lazy to do it over ;)

    Even if you use progressive linkage, I would still idle on both carbs.
    Jon.
     
    Last edited: Mar 18, 2018
    tb33anda3rd, jeepsterhemi and cactus1 like this.
  24. larry k
    Joined: Feb 23, 2009
    Posts: 546

    larry k
    Member

    Thanks MR carb king ,I will follow your instructions to the letter,and remember I also am from Missouri ,and you will know what that means ? My front carb runs fine on the rear same gaskets on both ends,I will let you know how the tests go from here???.Thank you for your help,I sure need it !!!
     

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