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Spark plug thread broke! ZZR250 thread still screwed in...

Discussion in 'Technical and Troubleshooting Torque' started by cptnrickstar, Dec 2, 2008.

  1. Hey all,

    I Was removing my sparks plugs to investigate a rattle I have in my engine (which I have another topic about), the spark plug came out but with no thread on it :(
    The thread from the spark plug is still in the spark plug place.
    I didn't force it, done it a few times with no dramas surprisingly it is an NGK (normally they are good quality?? or maybe not -must of been a cheap batch from factory)

    Does anyone know how to get around this and remove the thread? It is just hard to see and very deep down. Of course it is screwed in with nothing to grab onto! Man I have really had some bad luck with this bike :shock:
    Any advice on what to do in this odd situation would be great. :grin:
  2. Use an easy out. Just weld a socket to the end of the easy out so you can get it through the head with an extension connected. Spray some penatrine or simular down the hole and ther just screw it out. I have removed many spark plugs fron twin cam car engines this way before.
  3. Hi thanks for the reply, what excatly is an easy out??? Where would I get it?
  4. Hi again, Just searched google and found what you mean. Where is the best place to find an easyout? as it would be a particular thread because I have a small park plug. that idea of welding the socket to it makes sense.
    I just don't understand how the pieces of metal would come out wouldn't they go in the hole when I am using the easyout repairing the thread.
  5. You can buy easy outs from Bunnings. Buy quality though and not cheap stuff Sutton is a good brand but will cost about $70 for a set. The threaded portion of the spark plug is 1 piece and the easy out will just go through the centre of it and wind it out with nothing going into the bore. The thread will not be damaged using this method. This might be a job that you need profesional help with.
  6. Don't try to fix it yourself.

    It will be difficult enough to fix as it is and if you fcuk it up again you will be spending big dollars to repair the damage.

    Using an easy out will first require a hole drilled dead centre into the plug or the easy out will likely break. Even if you get the hole drilled correctly, easy outs break without too much effort. They are hardend steel which allows them to tap into the original bolt but it also makes them very brittle so care must be used.

    If the easy out breaks it will be expensive and frustrating for you. You may need to remove the head, find an engineer who does spark errosion and have them remove it at a price. Short of spark errosion, it can only be ground out with a carbide bit which in turn means drilling and re-tapping the thread with a helicoil.

    If you're desperate to try, then have a go yourself but make sure you soak the thread with penetrant and leave it overnight first (and remember that if you stuff it up you'll be fairly well fcuked).

    Of course you know you could have avoided this situation by being more careful. If plugs/bolts don't want to come out, use penetrant and let it soak in over night before trying again. Never try to force them or you will most likely break them (as you found). :)
  7. Hi all, I brought a set of easy outs from Bunnings. I got the easy out locked in the spark plug thread and with some luck it came out fine! I was able to also get a new spark plug in , no problems! Thanks for your help!!! Now I just need to get onto the camshaft noise that I might have!! This time I made sure I didn't tighten the new spark plug too tight!!
  8. Good job. :)
  9. You should lighty oil the plug thread, before you put it in. It is being threaded into alloy, so it will ease the process, and will help when you take it out again.
  10. What brand was the spark plug that broke? I remember doing about 10 cars in 1 week back in 98 that had this problem. The cars were Hyundai Excels with the twin cam engine. The genuine plug at the time was Champion. Hyundai changed to NGK for all models in about 99/2000 as we were getting heaps of spark plug related problems.
    The problem that you experianced is due to a manufacturing fault and not overtightening or dry threads.
  11. That is not necessarily true, mate. He could be "rough as guts" for all we know.
  12. Re: Spark plug thread broke! ZZR250 thread still screwed in.

    Maybe I / We should all read the OP again. He mentioned the brand as NGK, This is a surprise as they are good quality. He also mentions he did not force it. Unfortunately sometimes spark plugs do break. The porcelain part comes out and you are then left with the metal part left in the head. It is not a drama though as the easy out just goes through the centre of the old plug in place of the porcelain and they usualy come out easy.
  13. I have never had a problem with ngk, and use them exclusively.
  14. NGK + Denso is all i'd use.
  15. Torque settings can make a huge differance to spark plug removel.. :wink:
  16. The metal part with the thread is the bit with the hex on it. I wouldnt have though you could exert enough force on the plug to snap it before the head stripped.