Helicoil in cylinder block?

Discussion in 'Mechanics Garage' started by crynsie, Jun 13, 2010.

  1. crynsie

    crynsie New Member

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    One of my spark plugs was not tightened up properly at the last service and has been rattling around an stripped the thread in the cylinder head.

    I have two options, to try and find another cylinder head (hard and expensive) or get the thread helicoiled with a steel sleeve.

    Going back to the muppets who did the service is not an option so I am left with the two options.

    Has anyone helicoiled a spark plug cylinder and what were the results?

    Is it worth it for a short term option or just bite the bullet?

    Will the steel sleve react with the alloy head and what about the different heating and expansion rates (alloy vs steel in the same block)?

    TIA


    Si
     
  2. dwntwnsac

    dwntwnsac New Member

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    Well as as a guy who has come to realise that I know just about nothing of motorcycle mechanics. I have had quite a bit experiance with cars. And since I think I over torqued my first plug in a porsche 914 with aluminum heads. I used a steel healy coil to repair that little f-up. I drove the pis outa that car for two years over heating it more then a few times and even went so far as replacing the rings and reusing that head. I feel confident in recomending you try the coil first. I mean why not? What's the worst thing that's gunna happen? It fails after a few weeks or months and you're no worse off then you are now. But, and this might be my lack of kowlage on these V4,s I think it would be a good fix. The only thing I would worry slightly about is the metal shaveings droping in the cylinder. But a flexy mag. should take care of that. Hope my two cents helps.
     
  3. rodm850g

    rodm850g New Member

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    stripped threads

    crynsie,
    having gone through a similar repair of an aluminum headed Transporter then subsequent re-repair....the heli-coil is not the way I would go. I recently did a resto"refreshening" on my screen name sake...lost 5 of the 8 cyl head to the exhaust bolts. Havinghad experience with the brand name Time-sert was invaluable. The time sert is stainless and threaded inside and outside. Once in place there is a tool that comes with their kit that more or less stakes the distal end of the insert and locks it in place. Fastenal lists them in their catalog and there is a national company at wttool.com that has a complete list of their offerings and while this won't be a cheap set of tools it will save you the price of a head and will be good as new fix vrs. a coil of wire that could unravel.... good luck.....
    Rod
     
  4. CBR600F4i

    CBR600F4i New Member

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    +1 for Time Sert. I have the full set that covers every thread on the Caddy Northstar aluminum engine block, but I use them more often on bikes. They won't come out like Heli-coils.
     
  5. donald branscom

    donald branscom New Member

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    Heli coils have been around for 50 years.
    Take it to a machine shop and have them do it right.
    Also as far as the steel aluminum thing....Remember that the spark plug is steel too.So
    the aluminum /steel connection is still the same and steel and aluminum get along galvanically just fine.

    Also ONE more thing..... Always start spark plugs by HAND and they won't be getting stripped.
    Only remove spark plugs when the engine has cooled down.

    Time sert video...http://www.timesert.com/html/faq.html

    Ask the machinest about both.
     
  6. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    I have had success with heli-coil as well. It was professionally installed by guys that do them on a weekly basis. The heli-coil was installed with the head still on the engine.

    I understand that they will usually not guarantee/warranty the process.
     
  7. crynsie

    crynsie New Member

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    Thanks for all the replies.

    I will not be doing this myself as I have the mechanical aptitude of a small rodent.

    The helicoil option is one way to go but it will be done by a motorcycle mechanic shop.

    As has been noted they will not be able to put a warranty on the work.

    There is a cylinder block on david silvers site for 150 pounds and all up to nz will be 200 pounds (about 550 NZ)

    Still waiting for the shop to get back to me, I think they may be scared to tell me the prices...

    Thanks all, I will keep this up to date with the goings on.


    Si
     
  8. donald branscom

    donald branscom New Member

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    There is a lot of things in life that have no warranty. Don't worry about it.
    As far as the shop not wanting to tell you the price ....I doubt it.
    To put in one heli-coil they should only charge you about $20 max.

    The reason they probably cannot tell you price is ,is that they are going to take it to a machine
    shop and act as a middle man, and then charge you $150.00 for driving it over and picking it up, which they will pay some kid to do for $10.00 phr.

    WAKE UP!!! Just take that cylinder head over to the machine shop your self.
    Get it done and DON"T pay the motorcycle shop - especially when they don't have the heli-coils and do not know how.

    Just trying to help you from getting screwed. Thats all.
     
  9. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    disagree -

    a good shop will heli-coil it right on the motor. They grease the tap with a heavy grease and they turn the motor over to a position where the intake valves are closed and the exhaust valves are open. Then they apply a flow of air into the exhaust to create positive air pressure in the cylinder. Any chips that don't get trapped in the grease are forced to blow out of the cylinder thru the spark plug hole.

    donald's just bitter.
     
  10. donald branscom

    donald branscom New Member

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    "Donalds just bitter" Well yes I am. When I see motorcycle shops that cheat people, do poor work and do not have any experienced menchanics, I am down on them.
    When you want machining services go to a machine shop.

    What you say is right, as long as you can find "A good motorcycle shop."
     
  11. FJ12rydertoo

    FJ12rydertoo Member

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    +2 for the Time-Sert.
     
  12. dizzy

    dizzy New Member

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    I've installed both time-sert and heli-coil. They both work. Time-serts are a bit more elaborate and probably better. BRP recommends time-serts for thread repair on their products...that's a pretty strong recommendation.
     
  13. crynsie

    crynsie New Member

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    it's back

    Finally got my bike back yesterday and took if for a 250k ride. The engine is running sweet (I got a service as well) and new tyres which are sweeeeet (BT 023's, love em!)
    I am still scrubbing the tyres, but first impressions are great. The bike feels lighter at turn in and very little road noise (on the crap they call roads here... very coarse chip)

    All in all, very happy!!!


    Si
     
  14. donald branscom

    donald branscom New Member

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    Thanks for reporting back. Where is the PHOTO of the bike with new tires?
     
  15. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    it's back - but you didn't tell us which way you ended up going with the thread repair?
     
  16. crynsie

    crynsie New Member

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    Sorry tinkernstuff, went with the helicoil. The bike shop had to take the cylinder head off to get at it properly. Coast a little more, but I prefer that the mechanic does a good job rather than a fast job.

    I will try and get some photos up of the new tyres when I get some time.


    Si
     
  17. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

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    Guess I am not that surprised. The threaded part is very recessed from the top because of the cams and such. Glad you are back on the road.

    Were you given any instructions to insure lonGevity of the repair? I.e. Antisieze/torque spec? How was the cost? All important to know for the next guy who runs into this problem.
     
  18. crynsie

    crynsie New Member

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    Unfortunately not given a lot of detail of the repair, ie torque spec etc. The shop had their senior mech on it, but even then, they will not give a warranty on the repair as it is not a "honda" part (the helicoil) Anecdotal evidence is that it will last for a while (maybe a couple of years, maybe longer) but if it does decide to let go again, I will source a new cylinder head from David Silver spares.

    The cost was NZ $800.00. I guess that works out around 500 - 600US.

    Just a bouquet for David Silver Spares. I was quoted NZ$170.00 for an airfilter from Honda NZ. David Silver has them for 15 pounds (around NZ$30.00) I ordered online and it was here in 5 days. Very impressed with the service and the price.

    All up I paid NZ$1722 for the helicoil, service (oil etc), new BT023 tyres (approx NZ$680) and labour.

    Very happy to be back on the road again although very cold here (around 10 deg C). I know it gets colder elsewhere, but very cold for Auckland.


    Si
     
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