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1986 Cj7 popping noise out of the carb?

Discussion in 'Jeep CJ' started by Greg DrinkH2o, Jul 2, 2017.

  1. Jul 2, 2017 at 8:12 AM
    #1
    Greg DrinkH2o

    Greg DrinkH2o [OP] Member

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    Good Morning,

    I just bought a 1986 Cj7 258 IL6 that needed new head gaskets for 1800 bucks! Good deal or not? So before we installed the Gasket we had no popping sound coming from the carb. After install we have a very rhythmic popping sound from the carb. The sound is faster when you give it more gas. We think it might be a sticky valve. What do you think? Thanks in advance for your thoughts. Good deal or not?
     
  2. Jul 2, 2017 at 10:03 PM
    #2
    OFFGRID

    OFFGRID Well-Known Member

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    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    Is your timing set 6-8* BTDC? Sounds like the timing may be off. Make sure all of your plug wires are connected tight and the routing order is correct.
     
    JKBob 25 likes this.
  3. Jul 3, 2017 at 8:45 AM
    #3
    Greg DrinkH2o

    Greg DrinkH2o [OP] Member

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    Thanks for the great comment OFFGRID. I am currently at work and when I get back I will check those thing out and let you know what I find appreciate it!!!
     
  4. Jul 3, 2017 at 10:27 AM
    #4
    JEEP # 5

    JEEP # 5 Well-Known Member

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    Another thing you can do is pull the plug wires while the engine is running one at a time to isolate the cylinder. Then once you know the cylinder for sure, shut it down. Pull the plug, check compression in that cylinder. If the intake valve is sticking open, compression will be much lower then the others. This will also cause the popping or backfire. Same if the intake valve has a burned spot. This should have been looked at / inspected when the head was off. Lastly, before spending bucks on bigger issues, be sure to check the obvious easy to overlook items in the tune up list as Offgrid mentioned. IE Cap, wires, rotor etc.
     
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  5. Jul 3, 2017 at 12:38 PM
    #5
    Greg DrinkH2o

    Greg DrinkH2o [OP] Member

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    Thank you so much JEEP # 5!!! I will do all of those things awesome info!! What r some things that could cause the intake valve to stay open? And do you think 1800 was to much to pay for the old girl? Thanks again for the great info!!!
     
  6. Jul 5, 2017 at 7:14 AM
    #6
    JEEP # 5

    JEEP # 5 Well-Known Member

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    A valve can be sticky. A valve stem can be bent just enough. A Carbon built up ridge on the stem will can cause a sticky valve. But don't worry about these until you cover the basics first mentioned above. How many miles you have on this jeep? Jeeps hold their value very well. Good purchase will depend on after it is running right and investment that it took to get there.
     
  7. Jul 5, 2017 at 11:44 AM
    #7
    Greg DrinkH2o

    Greg DrinkH2o [OP] Member

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    OK great info Jeep # 5. So I am at work now when I get home the valve cover is coming off and hopefully I just did not seat on of the stems properly! I will post some more pics of the old girl soon so you can see what I am working with! Thanks again. Please have a safe and great day!!

    8-1-2017

    Hello everyone. For some reason I cant write a new reply so I am editing this one. So the popping has just gone away!! And now the cylinder closest to the cab is make a whole bunch of valve noise and no oil is come up to it? I am afraid the lifter or lifters are bad or not getting pressure. Can you pull the lifters out without taking head off?Thanks!!
     
    Last edited: Aug 1, 2017
  8. Aug 1, 2017 at 7:07 AM
    #8
    Greg DrinkH2o

    Greg DrinkH2o [OP] Member

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    So the popping has just gone away!! And now the cylinder closest to the cab is make a whole bunch of valve noise and no oil is come up to it? I am afraid the lifter or lifters are bad or not getting pressure. Can you pull the lifters out without taking head off?Thanks!!
     
    chris4x4 likes this.
  9. Aug 1, 2017 at 7:33 AM
    #9
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    JKBob 25 and Bob like this.
  10. Aug 1, 2017 at 9:22 AM
    #10
    Greg DrinkH2o

    Greg DrinkH2o [OP] Member

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    Thanks for the info Chris4x4. Great video!! I will let you know how it turns out. Appreciate it!
     
  11. Aug 1, 2017 at 7:08 PM
    #11
    JKBob 25

    JKBob 25 Well-Known Member

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    Finally a video from Chris4x4 that didn't leave me looking for my Meds with a drain bramaging song in my head. Lol.
    Very informative. Thanks Chris.
     
    Greg DrinkH2o [OP] and chris4x4 like this.
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