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Loud bang from the carb

Discussion in 'CJ' started by Jsims1973, Feb 24, 2019.

  1. Feb 24, 2019 at 10:58 AM
    #1
    Jsims1973

    Jsims1973 [OP] Member

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    Please help. I have a 77 cj5. I just did my break in on rebuilt 304 motor. It has eldabrock 600 and performance intake. My question is I'm getting a loud bang from carb. The higher the rpm the faster it is. I have ruled out a machanical issue. But no matter what I do it doesnt get better. I'm am beginning to think it could be vac leak of intake sucking air. I tried to upload a video but I wouldn't take it.
     
  2. Feb 24, 2019 at 11:26 AM
    #2
    Bob

    Bob Well-Known Member Moderator

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    Upload it to YouTube then paste the link to it in here
     
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  3. Feb 24, 2019 at 11:47 AM
    #3
    Jim Beam

    Jim Beam Well-Known Member

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    My first guesses would be ignition timing or to rich of a fuel mixture.
     
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  4. Feb 24, 2019 at 12:27 PM
    #4
    Jsims1973

    Jsims1973 [OP] Member

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    I have checked timing factory motor is 5° btdc I put it at 7° because of the cam. No matter were i move it it doesnt change. I could not adjust it out of the carb.
     
  5. Feb 24, 2019 at 12:37 PM
    #5
    Jsims1973

    Jsims1973 [OP] Member

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  6. Feb 24, 2019 at 2:51 PM
    #6
    Jim Beam

    Jim Beam Well-Known Member

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    The engine seems to sound good are you referring to that ticking noise?
     
  7. Feb 24, 2019 at 3:51 PM
    #7
    aggrex

    aggrex Well-Known Member

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    Based a bit off my Rochester Quadrajet carb days there was no backfiring thru the carb or banging on the video. Sounds more like lifter or valve noise which is not a good thing.
     
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  8. Feb 24, 2019 at 4:40 PM
    #8
    Jsims1973

    Jsims1973 [OP] Member

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    Yes
     
  9. Feb 24, 2019 at 4:43 PM
    #9
    Jsims1973

    Jsims1973 [OP] Member

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    I used a a screwdriver and held to me ear. Not any weird noise coming from valve covers. I plan on checking valves and rocket arms this week.
     
  10. Feb 24, 2019 at 7:24 PM
    #10
    JKBob 25

    JKBob 25 Well-Known Member

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    Agree. Thats not a backfire. Thats a top,end issue. Valve, rocker, lifter, or flat spot on cam. Either way. Not good. Sorry dude. Please post up updates. I'm sure we can help...
     
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  11. Feb 25, 2019 at 4:20 AM
    #11
    Jsims1973

    Jsims1973 [OP] Member

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    Finally got intouch with the builder. He said to check and adjust valves. Might have one to right causing valve not to close. I will check sometime this week. Thanks for all the help.
     
  12. Feb 25, 2019 at 2:27 PM
    #12
    Jsims1973

    Jsims1973 [OP] Member

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    20190225_170242.jpg problem found
     
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  13. Feb 25, 2019 at 3:54 PM
    #13
    aggrex

    aggrex Well-Known Member

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    Great! Always nice to discover and fix the problem!
     
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  14. Feb 25, 2019 at 4:34 PM
    #14
    Jsims1973

    Jsims1973 [OP] Member

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    I would like to thank everyone for the advice. I tighten the rocket back down. THE BOISE IS GONE. And didn't cost anything life is good.
     
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  15. Feb 26, 2019 at 5:20 AM
    #15
    TJ_abuser

    TJ_abuser Well-Known Member

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    Yeah that would do it must have had a nice miss also
     
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