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Thread: Spark Plug help

  1. #1
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    Default Spark Plug help

    Hello guys, I wonder if anyone can give me some advice please...

    I think I flooded my engine (26cc) on my Baja 5B as it wouldn't start, but to be thorough I removed the spark plug several times to check for a spark etc, each time I replaced the plug back it threaded in nicely. I have gone to screw it in again (just with fingers, no spanner) and for some reason after three or four turns it begins to tighten up! Fearing it being cross threaded i didn't force it.

    I have tried now a dozen times really carefully but everytime it begins to tighten after four turns.

    Any suggestions to what's going on (cross threaded?) and how to proceed?

    Thanks

  2. #2
    Baja-Forum Maniac llazaru's Avatar
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    If you have not forced it you could run a tap through it, head will have to come off though, can you not see if its damaged?

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    I have not forced it, but am confused to why its happened given that I haven't forced it? I can't see any damage on the head but the first few threads on the plug have that shiny look of a cross thread, so I have ordered a new plug, to try that first.

    if I had to run a tap down it, any idea what thread it is?

  4. #4
    Baja-Forum Maniac spentallmymoneyagain's Avatar
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    its not sommat as daft as the crush washers wound its way off or down the plug is it mate ?
    bit of a long shot but it is possible if the washers half way down the plug, ,
    but as laz says above, if theres damage then you would normally see it,
    also have you run the baja since you built it ?
    might be a bit of cruds got wound down the threads in the head if its been run ,ie; bit of grass or soil ,

  5. #5
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    Quote Originally Posted by spentallmymoneyagain View Post
    its not sommat as daft as the crush washers wound its way off or down the plug is it mate ?
    bit of a long shot but it is possible if the washers half way down the plug, ,
    but as laz says above, if theres damage then you would normally see it,
    also have you run the baja since you built it ?
    might be a bit of cruds got wound down the threads in the head if its been run ,ie; bit of grass or soil ,
    Nah wish it was something as easy as the washer, that is fine and where it should be!

    Yes I had the Baja running nicely last weekend.

  6. #6
    Baja-Forum Maniac spentallmymoneyagain's Avatar
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    Quote Originally Posted by Siholley View Post
    Nah wish it was something as easy as the washer, that is fine and where it should be!

    Yes I had the Baja running nicely last weekend.
    yeh what I was thinking was some crap from when you were running got onto the threads with taking the plug in and out mate,
    hence the tight spot,
    something I've found is that the actual plug threads are very easily damaged, I run tto temp sensors on my cars and you need to remove the crush washer to use em,
    I slipped with a pair of pliers and had the same issue as yourself, also I never went past the tight spot , tried a new plug and went straight in,
    plugs are cheaper than heads so hopefully you just somehow damaged the plugs threads

  7. #7
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    Quote Originally Posted by spentallmymoneyagain View Post
    yeh what I was thinking was some crap from when you were running got onto the threads with taking the plug in and out mate,
    hence the tight spot,
    something I've found is that the actual plug threads are very easily damaged, I run tto temp sensors on my cars and you need to remove the crush washer to use em,
    I slipped with a pair of pliers and had the same issue as yourself, also I never went past the tight spot , tried a new plug and went straight in,
    plugs are cheaper than heads so hopefully you just somehow damaged the plugs threads
    Yeah hope your right mate! Have ordered new plugs so will try that!

    Thanks for your advice and help, much appreciated

  8. #8
    Baja GEEK! Baja5b-SS's Avatar
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    You haven't over torqued the plug have you? This will round off the head threads, could have ripped threads on the way out.

    Did the plug come out once undone with your fingers or did you after keep wrenching on it to remove.

    If the threads are fked on the head it's not the end of the world heli coil kit will fix the head.
    CNC milled carbon fibre/Aluminium baja/losi parts stock, modified and custom.





  9. #9
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    Quote Originally Posted by Baja5b-SS View Post
    You haven't over torqued the plug have you? This will round off the head threads, could have ripped threads on the way out.

    Did the plug come out once undone with your fingers or did you after keep wrenching on it to remove.

    If the threads are fked on the head it's not the end of the world heli coil kit will fix the head.
    No I doubt it as I only nipped it up. It went in and out several times quite happily and then the next time went tight! The time it went in before going right was with finger pressure only!

    I'm thinking (hoping) that it's the thread on the spark plug and not the head.

    Have ordered a new plug so will try that.

    Worst case scenario, if it is the head then new bigger bore head kit :-)

    If I knew the thread size of the plug I could always gently run a tap down it.

    Cheers

  10. #10
    Baja GEEK! Baja5b-SS's Avatar
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    Worse case new head heli coil 10-20 threads M10x1
    CNC milled carbon fibre/Aluminium baja/losi parts stock, modified and custom.





  11. #11
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    I'm on holiday from today for two weeks, so will let you all know how I get on when I return. Gutted I couldn't run my buggy today before I went but at least it's something to look forward to when I get back.

    Thank you all so much for your advice and help!

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