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Technical Carter WCFB tech

Discussion in 'Traditional Hot Rods' started by carbking, Dec 15, 2013.

  1. Mikeszcz
    Joined: Apr 5, 2011
    Posts: 296

    Mikeszcz
    Member
    from Winona, Mn

    No yea or nay so I'm just going to go ahead, do a stock rebuild and give them a try. I have a run in stand that I can play with, but the real test won't be until spring. I'll be sure to post a report.
     
  2. UNSHINED 2
    Joined: Oct 30, 2006
    Posts: 1,164

    UNSHINED 2
    Member

    Mike,
    Do you have any idea as to the vehicle these were used on?

    I have a decent small base WCFB off a 54 Olds. Trying to find model specific carbs can be a chore, does ANYONE know if I can just use any small base/same body/same top combo to go with it? Or does it have to be make/model specific in a 2 x 4 setup?

    With the same jet sizes...pump size..etc, of course.

    301cu. in., Weiand wcv283 intake...375-400hp
     
  3. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    Regardless of what you may read elsewhere, it is virtually IMPOSSIBLE to identify most Carter type WCFB carburetors by casting numbers alone. The casting numbers are just that - casting numbers for a "blank" (not yet machined) casting.

    Unless you can totally identify the untagged carburetor, for best results, put it in your "spare parts bin". No, don't send it to me, even though I have custody of the Carter drawings, and can identify them. I know how much time it takes, and not willing to spend the time.

    Do your homework like you would with any other carburetor (determine necessary carburetor size for the application), and, for dual four use that is not factory, look for MATCHING BY TAG NUMBER carburetors to fit the bill.

    A calibration tip: with original carbs you have Chevrolet calibrations, and everything else calibrations. If you are building a Pontiac, MUCH easier to start with 2 Dodge carbs (of the appropriate size) than 2 Chevrolet carbs. I am NOT saying that one could not make the Chevrolet carbs work if one is independently wealthy, but much easier as well as cheaper, to start with something with at least a similar calibration. How many different pairs of WCFB metering rods do you have???

    Finally, internal combustion engines are quite forgiving. You can run the engine by having a teen-ager stand on the running boards, and pour gas into the engine from a leaky boot! :p You can also do matching carbs of the proper size, and get better results!:D

    Jon
     
  4. saltracer219
    Joined: Sep 23, 2006
    Posts: 1,071

    saltracer219
    Member

    Mike, your 1672 tops are off of 62-65 Chev and Corvette 327-250 hp. the "1576" top is probably a 1376 used on 60-61 348 pass cars. The 1465 main bodys are from a 64-65 Chev pass and Corvette. You should be able to use Carter #3696s as a reference number for the kits. They should work well for your project as they are in the 500 cfm range. You will have to experiment with metering rods and jets, however you should be able to baseline them using the stock rods and jets to start with. repro jet,rods and piston springs are available if you need more info P.M. me, Gary....
     
  5. Mikeszcz
    Joined: Apr 5, 2011
    Posts: 296

    Mikeszcz
    Member
    from Winona, Mn

    I've heard of some drag racers pulling the metering rods out and going to using Holley jets for tuning. Good idea/bad idea? I'm going to start with stock rebuilt carbs as suggested for the summer, but I know I won't be able to keep myself from messing with them. Any suggestions?
    Thanks, Mike
     
  6. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    It may be done FOR RACING ONLY, HOWEVER:

    (1) This should absolutely NEVER be done on the street! Why? Carter's metering rod technology serves as a much more sophisticated version of Holley's power valve. If you eliminate the metering rods and calibrate the jets alone, the engine will go super lean when you ask for power on the street.

    (2) For racing, metering jets are much less expensive than metering rods, so depending on one's tuning skill, one may initially save some money BUT:

    (3) To replace the jets (tuning at the track for varying temperature, humidity, drawing the wrong lane, etc.) the air-horn must be removed to change the jets, meaning the racer should probably buy air horn gaskets by the hundreds. If one calibrates with metering rods, very simple to simple remove the cover and change the rods. And while I don't recommend this as normal operating procedure, to prove how simple the change is, I have actually changed rods WHILE THE ENGINE IS RUNNING. Two minutes to change the rods, fifteen minutes to change the jets.

    So, if a street car, DON'T DO IT.

    If a race car, consider the above, and decide what works best for you.

    Jon.
     
  7. Mikeszcz
    Joined: Apr 5, 2011
    Posts: 296

    Mikeszcz
    Member
    from Winona, Mn

    Thanks Jon, appreciate the advice!
     
  8. bchctybob
    Joined: Sep 18, 2011
    Posts: 5,190

    bchctybob
    Member

    [QUOTE="carbking, post: 12271688, member: 70250"
    Finally, internal combustion engines are quite forgiving. You can run the engine by having a teen-ager stand on the running boards, and pour gas into the engine from a leaky boot! :p You can also do matching carbs of the proper size, and get better results!:D Jon[/QUOTE]
    I had to laugh at this comment.... Waay back when I was 14 or 15 my Dad took me to the wrecking yard to buy a carb of my choice to learn on, I picked a Rochester 4 Jet from a '57-'58 Olds - it was a beaut. My carb ended up going out on loan among the neighborhood hot rod guys to whoever needed it at the time.
    My neighbor Lance borrowed it to try on his hot rod '55 Buick. We installed it and then he went on vacation with his parents. While he was away I went over and removed my carb so we could put it on another buddy's car to run at Lion's that weekend. He came home and without opening the hood, started up his car - with no carb! The fuel line was pointed right into the manifold opening so it ran - sort of. It stalled, and Lance thought the gas pedal felt like it wasn't attached to anything so he looked under the hood. No Carb!
    He was pissed at first but we all got a good laugh at how it started and ran with just a big opening in the manifold. I guess I shoulda left him a note but I was only 14 or 15 and too excited about going to Lion's to consider the consequences.
    We never thought much about CFM and circuits, if it was bigger, if you could bolt it on, hook up a fuel line and the accelerator linkage, it was perfect...... I've learned a little since then.
     
  9. flypa38
    Joined: May 3, 2005
    Posts: 530

    flypa38
    Member

    Hey, Jon! There was a service bulletin for my '56 Pontiac when it was nearly new to fix "stalling on left turns". It involved putting a small tube into a passage to prevent fuel from getting into an air passage or something.......
    Any idea where I might be able to find the tube and/or more information on it?
     
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  10. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    We probably have them around here somewhere, but don't know where ;), and when I needed one, I simply made one on the lathe.

    GOING FROM MEMORY!

    The tube is approximately 3/8 inch long.

    The O.D. is slightly larger than the I.D. of the vacuum passage running through the bowl to the air horn.

    The procedure is to mill a hole approximately 0.001 SMALLER in I.D. than the O.D. you make the tube in the top of the bowl in the vacuum passage approximately 3/16 inch deep.

    Place the tube in the freezer overnight. The next morning, heat the bowl in an oven to maybe 250 degrees F. Remove the tube from the freezer and press into the hole in the bowl.

    In the air horn, mill a hole in the passage slightly LARGER than the O.D. of the tube approximately 1/4 inch long.

    The second design of the air horn to bowl gasket had a slightly larger hole to accommodate the tube.

    The "patch" prevents fuel slosh into the vacuum passage on hard left turns if the gasket should be slightly deteriorated.

    This "patch" is applicable to all WCFB and Rochester 4-GC carbs with the air horn mounted heat tube choke.

    It is not necessary on units with the choke mounted on the bowl.

    Jon.
     
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  11. vetteson
    Joined: Oct 7, 2010
    Posts: 301

    vetteson
    Member

    Carbking Jon,

    On the first page you described the early WCFB "air valve". Was this a large screw that entered and penetrated the throttle body? It passes through one of the screw holes for attaching the bowl and throttle body. I have one on my '56 Cadillac WCFB that I've been using on a 331 Cadillac engine. If so is there any info. on adjusting it? Right now I have it screwed in about "half way".
     
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  12. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    The air valve, if used, was a second set of secondary "throttle plates" (actually air valve plates) which were located above the actual secondary throttle plates.

    The screw you are describing is the "idle air screw" (a.k.a. idle air bypass screw). This is a "metered internal air leak". The suggested initial setting, depending on the tag number of your carb, is to screw it in until "thumb tight", and then back it out from 1 to 1 1/2 turns.

    Jon.
     
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  13. vetteson
    Joined: Oct 7, 2010
    Posts: 301

    vetteson
    Member

    Thanks!
     
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  14. Mikeszcz
    Joined: Apr 5, 2011
    Posts: 296

    Mikeszcz
    Member
    from Winona, Mn

    Tested the 2-4's today. A couple things that may have slowed us down from the get-go. We switched from a 9" radial to a 7" bias tire and I know that killed a tenth from what we were running. We also are comparing the dual wcfb's to an NHRA prepped Q-Jet and messaged manifold that I know are great pieces. Plus it was hot and humid today also. We also sidelined the larger carbs in the ealier posts for a 1956 carb and a Chris Craft replacement carb that was like new and too hard to pass up on. I wanted the high choke mount to fit the period correct look of our 56. We started with .094" jets in the front and .053" in the back of both carbs. We started with .050" metering rods and tested .055" and then .060" and were still rich according to our AFR numbers. 10.5, 11.0 and 11.5 respectfully. Our 60fts weren't all that great, but on the last pass we doubled up the spring on the accelerator pump and that seemed to wake it up. Our car ran 12:70's with the old combo and the best we could do today was 13:10. Same track, but very different weather conditions. I'm thinking about ordering some smaller jets and looking into some acc pump options before next weeks Meltdown drags.
    Thanks, Mike
     
    Last edited: Jul 25, 2018
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  15. Dose anyone make these springs for the throttle linkage?

    Carter spring.jpg
     
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  16. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    PM sent.

    Jon.
     
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  17. j grady
    Joined: May 14, 2012
    Posts: 6

    j grady
    Member

    HI Alex..I have the identical problem, makes no sense ---on 325 Dodge Poly (57) all rebuilt carb. I had a lot of backfires ,(stuck valve at first) , may have hurt carb somehow, Does it with no linkage attached and action is very powerful, not easy to just overcome it . Would take a huge spring to overcome, not practical.What the H is going on? you ever get it fixed?? Torqueflight car , huge surge at any old time engaging --dangerous. Let me know. You never got an answer here that makes any sense....I understand what you are saying. Best regards, John
     
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  18. Jon... Just found this thread, some really great information. Now, my question...

    I have a 1953 Olds Carter WCFB that is missing the accelerator arm bushings for the throttle linkage, 0.3125 (5/16") ID X 0.21875 (7/32") OD. Do you have or do you know of a source for these? Thanks...
     
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  19. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    Was not aware that any of the WCFB's, other than Chevrolet, used throttle bushings. No, I am not aware of a source, but should be very easy to make on a lathe.

    Jon.
     
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  20. Thanks Jon...
     
  21. jimmy six
    Joined: Mar 21, 2006
    Posts: 14,799

    jimmy six
    ALLIANCE MEMBER

    I've 2 Carter 1953 Olds WCFB's for my dual quads and they do not need a bushing. Same with the 1953 Cadillac one also. What is your tag number#?
     
  22. I am most likely calling theses by the wrong name, here are some pictures of what I am talking about...
    32.JPG
    100_1803.JPG Sorry about the shitty picture but you can see hole (lower right) where I need the bushing for...
    100_1804.JPG
    … this piece.
    100_1805.JPG
    Again, sorry about the picture quality!
     
  23. Our True Value hardware store locally has a huge hardware section that has several trays of bushings, both nylon and brass. I have been able to find bushings there often to help in my projects fwiw.
     
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  24. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    While this item is attached to the carburetor, it is technically not considered a carburetor part. This is a portion of the "rocker" linkage used by Oldsmobile on this as well as other carburetors.

    In this case, Carter supplied the throttle body with a large drilled and tapped boss. Everything from there (stud, rocker assembly, etc.) was supplied by Oldsmobile.

    I would try FLAPS for bushing assortments; and if no love, then antique Oldsmobile vendors. If unsuccessful, should be very easy to make one on a lathe.

    Jon.
     
    saltracer219 likes this.
  25. Thanks again.
     
  26. saltracer219
    Joined: Sep 23, 2006
    Posts: 1,071

    saltracer219
    Member

    I have made these and similar bushings from Moly filled nylon (nylatron) rod. Available from McMaster Carr and other sources. Self lubricating and lasts just about forever.
     
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  27. ddiaz396
    Joined: Aug 5, 2012
    Posts: 9

    ddiaz396
    Member
    from florida

    Hi, just rebuilt my Carter WCFB carb in a 1956 Buick Super sedan, and I have some questions...Is the orientation of the swing vacumeter piston at the piston link important? How do you place the piston and the spring back in the cylinder hole?(put the spring first and then lower the air horn with the piston already attached?)Is there a trick how to place the metering rod in the jets on the same operation?(is done but it was very difficult!). The 4 metering jets(2 primary 2 secondary) have same number?? Thanks.
     
  28. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    QUOTE "Hi, just rebuilt my Carter WCFB carb in a 1956 Buick Super sedan, and I have some questions...Is the orientation of the swing vacumeter piston at the piston link important? How do you place the piston and the spring back in the cylinder hole?(put the spring first and then lower the air horn with the piston already attached?)Is there a trick how to place the metering rod in the jets on the same operation?(is done but it was very difficult!). The 4 metering jets(2 primary 2 secondary) have same number?? Thanks."

    "Is the orientation of the swing vacumeter piston at the piston link important?" Piston NO, link YES. the tab on the link faces AWAY from the linkage.

    "How do you place the piston and the spring back in the cylinder hole?(put the spring first and then lower the air horn with the piston already attached?" You nailed it.

    "Is there a trick how to place the metering rod in the jets on the same operation?(is done but it was very difficult!)" NO, NEVER, DON'T EVEN THINK ABOUT IT, LET ALONE TRY IT!!!!! ALWAYS (and I seldom use this word) place the airhorn onto the bowl, snug the attaching screws, and THEN install the metering rods. They will slip into place easily. Ignore this advice, and I sell metering rods to replace those you broke! As they are made on a manual prototyping lathe, they are NOT cheap!

    "The 4 metering jets(2 primary 2 secondary) have same number??" NEVER believe numbers stamped on jets! Use orifice drills (or drills from a numbered drill set) and MEASURE! With Carter 4-barrel carbs, the larger jets will be on the primary side (even though the secondary bore is larger) because the metering rods extend into the primary jets. I doubt very seriously if the primary and secondary jets are the same size.

    Jon
     
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  29. kilohertz
    Joined: Oct 5, 2020
    Posts: 74

    kilohertz
    Member
    from Vernon, BC

    Hello all,

    I am in the process of restoring my '49 Ford F-1 and it has the 239 Flathead in it. Planning on mild street rod and am starting to "hot rod" the engine. I have found an Offenhauser 4 bbl intake and was planning on the Holley 390 CFM but they are stupid pricey and requires an adapter plate so I am looking for an original small base carb, such as the WCFB. I have now found 2 of them, one compete except for choke coil and mixture screws, tagged 2333S and a core tagged 2354S, missing butterflies and choke coil, mixture screws, probably some other things as well. The mostly complete one is missing the idle mixture screws and my reason for posting is that, are there any other idle mixture screws that will work in this WCFB carb? I see reference to Rochester in numerous searches for the WCFB carbs. I know nothing of the history of Carter and Rochester but perhaps there is some crossover.

    I have a friend that has a few of the larger base 4GCs he said I could have for parts. Any idea if the old 4GC, larger base than WCFB mixture screws would work? Any other carbs' mixture screws that would work?

    Any other small base carbs you could recommend for the flathead?

    Thank you.

    Cheers
     
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  30. carbking
    Joined: Dec 20, 2008
    Posts: 3,715

    carbking
    Member

    Carter used at LEAST a dozen different idle mixture screws on the various models of the WCFB.

    Rochester used several, and they would not interchange with the Carter.

    The very best carburetor (opinion) for your application would be the Carter WCFB 2191s.

    The WCFB 2333s you mention should work fairly well AT ABOUT 8000 RPM'S.

    If you should decide to go forward with that carburetor, the idle mixture screws do come in the better rebuilding kits.

    Jon.
     
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