Viewing 18 posts - 1 through 18 (of 18 total)
  • spark plug bagginess
  • jedi
    Full Member

    having snapped a spark plug in my corsa we used an easy out to get the thing out but now the threads are ruined.
    the plug is baggy when fitted and not tight fit. are there any fixes that dont involve taking engine apart or buying a van?

    oneoneoneone
    Free Member

    not sure if some ptfe tape will do?

    if not some sort of lock tight

    nasher
    Free Member

    That sparg plug will be under extreme pressure and heat.

    Maybe loctite do some special paste, but i think you may be F*&^%$d

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    dave_aber
    Free Member

    There is a threaded insert you can get which you screw into the head. Involves making the hole bigger with a tapered tap – use lots of grease to trap the swarf and keep most of it out of the engine.

    Best bet is to go and ask your local engineering workshop if you have one – the sort of place that can skim cylinder heads, regrind cranks, etc.

    jedi
    Full Member

    🙁

    TandemJeremy
    Free Member

    Wot dave said – you can helicoil a spark plug thread – and if you grease the tap heavily most of the swarf stays on the tap so its a five minute job without dismantling the engine. To do it properly you need to remove the cylinder head but a helicoil without removing the head is possible

    toys19
    Free Member

    wot dave and tj said, don't be tempted to use ptfe tape or loctite as you need to earth the plug through the engine block otherwise it wont spark!

    dave_aber
    Free Member

    The one I used (many years ago mind) was more like a pipe threaded internally and externally than a traditional helicoil (like a spring). It had a certain amount of 'wall' there too.

    One tip I got was once the new, bigger, thread is cut, clean off all the grease. Get the external thread wet, with water, before screwing it into the head. Grease the spark plug before you screw it in. The idea is to encourage the 'repair' to seize into the head over time, and not unscrew with the plug on the next service.

    This baby should do it and be cheaper than taking the head off.

    s8tannorm
    Free Member

    Don't grease the spark plug thread, the grease can't take that kind of heat and will become a horrid gungy mess, it'll also make the plug run hotter and stop it earthing through the head … instead, rub a pencil over the threads this will lubricate them without causing problems.

    Better than a helicoil would be a 'Time Sert' made by a company called Wurth. There's plenty of car garages out there with them, have a ring about and tell them you'll take the risk of doing it with the head in place.

    s8tannorm
    Free Member

    Jedi … I've just thought. What size plug is it?

    If it's a 10 or 12mm then you might just get away with re-tapping the next size up. You'd have to run a mixture of plugs but it's not the end of the world.

    If it is 10 or 12 and you're not in a desperate hurry let me know as I've got taps, I could pop one in the post to you. If you need it in a hurry a tap should set you back about a tenner. You'll need either 12×1.25mm or 14×1.25mm.

    Cheers Stuart

    jedi
    Full Member

    i think its time to get another vechicle 🙁

    fergusd
    Full Member

    Helicoiling spark plug threads is not uncommon, difficult or expensive . . . once repaired it'll be as good as before . . . without doubt it'll be cheaper to fix it than replace it . . . I would never consider anything other than a helicoil repair and if you are not completely confident, you need to find someone who has done a few . . . local engineering shop would be the place to speak to . . . and find whoever overtightened the plugs last time and kive them a kick up the arse . . .

    Fd

    toys19
    Free Member

    Tony,
    You cant just tap it, has to be drilled.

    Just had a chat with my brother who is an aircraft engineer for flybe, before that he used to work on piston engined prop planes, he has done this job all the time.

    They do it with the head on, but the exhaust removed so you can suck the swarf out as its produced, and then flush it out after, any tiny bit of dust on (if its alloy) apparently get burned up. He reckons most car places do it without removing anything and just suck the swarf out..

    He was keen on doing it for you in return for some jedi training credit but he's in Cov and hasn't got time to go to MK…

    2unfit2ride
    Free Member

    Try this, available here, you never know, it can withstand the temperature & you could always run a separate earth to the plug if needed.

    🙂

    Cheers.

    jedi
    Full Member

    gunna try liquid metal

    2unfit2ride
    Free Member

    Check the heat rating, the above will take heat well.
    Cheers.

    stratobiker
    Free Member

    Put the end of the plug in a vice and very carefully squeeze it a bit so as to ovalise it a little thereby making it bigger across.

    SB

    knottie8
    Free Member

    2nd what strato said or fit a helicoil ,there must be someone on here who lives local and can fit a helicoil for you .

Viewing 18 posts - 1 through 18 (of 18 total)

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