Coil snapped - half stuck on spark plug

Discussion in 'Mechanics Garage' started by UnclePieface, Nov 4, 2017.

  1. UnclePieface

    UnclePieface New Member

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    Hi all.

    First post, hoping you can help me, aaaarrrgggghhh!

    You know when you do a job and it goes well until....

    Yep, that's me. Removed front left coil today and only half of it came out of the cylinder head. Other half is still in there and sat on the plug.

    Any tips on how to get this bugger out without a massive strip-down please? Pic of coil to follow...

    Thanks in advance one and all.

    U.P.
     
    Last edited: Nov 4, 2017
  2. UnclePieface

    UnclePieface New Member

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    That's the bugger :(
     

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  3. OZ VFR

    OZ VFR Member

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    You should be able to use long nose pliers to fish it out.
     
  4. UnclePieface

    UnclePieface New Member

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    Nothing to grip Oz.

    That's the problem.

    So, I tried to degrease, got a wooden spoon, put a blob of Gorilla Glue on the end and pushed the long handle down the hole onto the bugger. I've left it overnight and am praying I can get it out today.

    If this doesn't work, is the core able to take a drill do you think? [​IMG]

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  5. OZ VFR

    OZ VFR Member

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    No, I wouldn’t try to drill. The plug is still intact.
    I would try a couple of long thin screwdrivers on opposite sides and try leavening it.
    The cap is only held to the plug by a spring clip.
    It shouldn’t be that hard to remove.
     
  6. OZ VFR

    OZ VFR Member

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    That central metal bit you see should be the top of the plug. The rest is the plug cap.
     
  7. UnclePieface

    UnclePieface New Member

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    No, it's not the top of the plug Oz, there's a substantial bit above the plug itself. The difficulty is getting purchase. The finest thing I've been able to get down the sides has been a junior hacksaw blade, but it's not working. Wondered about vacuum cleaner with a really small hose cobbled onto it to "ventouse" it out? If it worked on my son when he was born then......



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  8. Diving Pete

    Diving Pete Member

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    epoxy would be my suggestion. Use an old socket that fits over the coil but down the hole. Put an extension on the it, place epoxy into the socket - DONT FILL IT then lower it over the broken bit of the coil. You will not need much. Then Wait till it cures - depends on how much hardener you have put in - lol
    lift out...

    You may also manage this with hot glue...
     
  9. UnclePieface

    UnclePieface New Member

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    Got it!

    Look at the state of it. I'm trying to suss how it was so mangled. I pulled it straight out so all this had occurred previous to me owning the bike. Strange.

    Any thoughts anyone? [​IMG]

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    Last edited: Nov 5, 2017
  10. UnclePieface

    UnclePieface New Member

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    Check this out.

    I think the spark plug came loose enough to still fire but heat travelled out of the plug port and slowly destroyed the rest of the coil.

    Knackered threads too. Worrying. [​IMG]

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  11. bigbadbass

    bigbadbass New Member

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    It would be a miracle if the cyl head plug threads are not damaged ...let alone further internal damage caused by broken, missing sections of spark plug.

    A genuine cause for great concern there...further *very close* inspection is called for.
     
    Last edited: Nov 5, 2017
  12. OZ VFR

    OZ VFR Member

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    ^ I agree, there is some serious heat damage there from hot gases bypassing the plug.
    I doubt the plug was tightened at all.
    Don't forget the head is made of softer metal than the plug, and the plug is melted.
    I would think it would at least need a new head, or an easycoil installed on the offending plug hole.
    Either way you will need to remove the head.
     
  13. UnclePieface

    UnclePieface New Member

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    What I would say there though Oz is that the head on the inside of the combustion chamber is the same metal as the threaded portion where the plug goes. I can't see that it would melt. It's clear to me that the coil assembly would have overheated and died though.
    Of note, all four plugs were loose. One took four whole turns to tighten.
    This was after the previous owner had the spacers checked...... or did he??

    Pic shows plug removed. Bit of debris to get with tweezers down there I see. [​IMG]

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    Last edited: Nov 5, 2017
  14. OZ VFR

    OZ VFR Member

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    The plug seat looks fine.
    You can just install new plugs and coil pack, take it for a ride and reinspect.
    It might be OK, I would keep inspecting for the next few weeks just for peace of mind.
     
  15. UnclePieface

    UnclePieface New Member

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    I think that's what I'll do Oz. Fingers crossed .
    Thanks for the help gents.

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  16. J800VFR

    J800VFR New Member

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    Personally, with that much damage to the coil and spark plug, I'd seriously consider inspecting the inside of the combustion chambers, piston crowns and the plug threads in the heads.

    At the least, and with the lowest cost would be to get one of those fibre optic inspection cameras (they're available almost everywhere now, including Amazon and Ebay and I've even seen them in Aldi & Lidle) .

    If there is any signs of pitting or damage, beyond normal age & mileage related wear, it's a case of head removal and refurb or replace.
     
  17. bigbadbass

    bigbadbass New Member

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    Just how could a damaged spark plug of that nature *NOT* cause damage to the cyl head threads on the way out? I'd consider it a miracle if they are *truly* intact.

    The spark plug must thread in all the way and additionally capable of being adequately torqued to spec...intact threads are critical to achieve.
     
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  18. J800VFR

    J800VFR New Member

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    I'd be very concerned to ensure that none of the debris from the damaged spark plug has fallen into the combustion chamber.

    Although these are not the most highly tuned engines they still run a reasonably high compression ratio.
     
  19. UnclePieface

    UnclePieface New Member

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    I'll do my best but bottom line is that it failed to fire on that cylinder 100 miles from home. Middle of nowhere so had no choice but to keep riding. I suppose the acid test is when I try and get that pot to fire when it's got a new coil and plug.

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  20. J800VFR

    J800VFR New Member

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    Then that makes it essential that you find out whether there's any internal damage, which I'd do before simply replacing the plug and coil and starting the engine. You could do more damage.

    As you should have the spark plug threads in the head fully inspected and possibly repaired (helicoil is possible) that will require to remove the head, which makes it easy to fully inspect the cylinder bore, combustion chamber, valves and piston crown.

    If any parts of the broken spark plug had dropped down into the cylinder whilst the engine was running then there's a strong likelihood of internal damage including scoring of the cylinder liner.

    If the damage is extensive than you have to choose whether to have it professionally repaired or possibly cheaper to buy a good used engine (such as from a crash write-off) with low mileage and do a direct swap, but the new engine would also be a bit of an unknown quantity unless some guarantee is included or you're buying from the original owner.
     
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