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Backfire through the carb on a '59 352

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    Backfire through the carb on a '59 352

    I've finally wired up the electric fuel pump and car seems to idle great. It runs ok, but does occasionally backfire through the carburetor. I recently rebuilt the carb, but I feel that I don't have it adjusted correctly. Tried to check the timing and couldn't find the timing mark on the damper. Any suggestions on how to fix this?

    Also, after idling for awhile, when I start it back up when hot, it takes several cranks and my accelerator pedal on the floor. Could these two issues be related?

    Thanks for the help.
  • jopizz
    Super-Experienced


    • Nov 23 2009
    • 8308

    #2
    As far as the backfire it could be timing related or carburetor related. A misadjusted choke will cause backfiring. It could also be running too lean. How did you adjust the mixture screws after you rebuilt it. The best way is with a vacuum gauge. I would try and adjust the timing first. The timing marks are there on the edge of the damper. You may need to use some sandpaper if the damper is rusty. Hard starting when hot could be an indication that the timing is too advanced. It could also be an indication that the choke isn't open all the way.

    John
    John Pizzi - Squarebirds Administrator

    Thunderbird Registry #36223
    jopizz@squarebirds.org 856-779-9695

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    Comment

    • Dakota Boy
      Super-Experienced
      • Jun 30 2009
      • 1561

      #3
      Carb backfire means a lean condition somewhere.

      Backfire out the tailpipe equals a rich condition.

      My car would cough back through the carb last summer when the engine was cold. I adjusted the accelerator pump (Holley 3310 carb) just a bit, and the problem went away.
      http://www.tbirdregistry.com/viewdat...ryNumber=33517

      Comment

      • lawyercalif
        Experienced
        • May 12 2011
        • 240

        #4
        Not enough timing advance will cause backfire through the carb. Try advancing the distributor a little at a time and see if it goes away.

        Comment

        • simplyconnected
          Administrator
          • May 26 2009
          • 8778

          #5
          Burned or mal-adjusted (open) valves will also cause backfire.
          Member, Sons of the American Revolution

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          Comment

          • Astrowing
            Experienced
            • Jul 22 2009
            • 478

            #6
            If you can't locate the timing mark on the damper, you can go through Dave's procedure on degreeing an engine to determine where TDC is located. Once you've done that you can mark TDC on your damper.

            I would guess the timing is not correct also causing the backfires.
            sigpic

            CLICK HERE for Jim's web site

            Comment

            • rln31455
              Newbie
              • Jul 30 2004
              • 22

              #7
              All of the above should be checked to correct your problem. One more thing to consider is induction firing. The firing order is 1-5-4-2-6-3-7-8. Cylinders 7 and 8 are next to each other physically and in the firing order. If the spark plug wires for these two cylinders are routed parallel to each other voltage can be induced to the wire that has no voltage passing through it. A magnetic field is formed around a wire when current passes through it. If a wire is passed through a magnetic voltage is created. Think of your generator. When spark is fired on one cylinder a magnetic field is created. When the spark terminates the field collapses. This will induce voltage in the wire that the magnetic field has passed through. Think of your ignition coil. This causes your backfire. This is common on Fords with this firing order. To correct this problem be sure that the spark plug wires are not routed parallel to each other. Try to cross the wires at a 90 degree angle when you clip them to the valve cover. I was talking to an owner of a perfectly restored Galaxie at a cruise night. He could not correct an intermittent backfire. I explained induction firing to him and rerouted his plug wires. I saw him later in the summer and he said his problem was corrected. This is just one more thing to be aware of. Be sure to check all of the above first. Good luck.

              Comment

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