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Thread: First major disaster.

  1. #1
    Join Date
    May 2009
    Location
    Nottingham
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    3,604

    First major disaster.

    Well yesterday was the first major disaster in a long time.
    Had an exhaust stud snap clean off at the cylinder head
    So had a go with a really good carbide drill to hand drill it out. Which was going very well untill it came to the end of the stud.
    And with the small amount of presssure I was pushing. It went like butter through the alloy into the cylinder water jacket.
    Don't see any way off repair. After re threading and tightening a bolt in it leeks when filled with water.
    I pressume 11 and 12 heads are different?

  2. #2
    Join Date
    Jul 2005
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    Scotland (West of)
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    Re: First major disaster.

    What you want to do is tap it out a larger size (10mm or a BSP size) and get a stepped stud made with an 8mm thread at one end and the larger size at the other.

    Fit it to the head with a decent thread sealer or alloy cement and you will be good to go.

    OR - drill / mill the stud hole out to accept a threaded bush and get it welded in.

    Either way it would be better if the head was removed.

    Kendo
    Take the pieces and build them skywards !

  3. #3
    Join Date
    Jun 2014
    Location
    Norf East
    Posts
    8,062

    Re: First major disaster.

    Phil,

    Whilst I fully agree with Kenny, a head on fix attempt (I suspect you have little to lose) might be that if your thread is ok would be to get some JB weld (not the shite from Halfords) and use it as if it were a thread lock, butter the stud and get a bit in the hole before hand (not enough to block the water jacket).

    Its good stuff and got me out of several bad situations

  4. #4
    Join Date
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    Location
    Nottingham
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    Re: First major disaster.

    Thanks guys I suppose its worth a try.
    With something like this stuff ? or other recommendations. :- http://www.ebay.co.uk/itm/JB-Weld-Hi...item541bd0f811
    Middle cylinder so will get very hot.

  5. #5
    Join Date
    Jul 2005
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    Scotland (West of)
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    Re: First major disaster.

    What state is the original thread ?

    If it is good and not too loose then the cement may work , if it is fucked then you will be asking a lot for the cement to seal and retain the stud once the exhaust is tightened up.

    If you slap too much cement on the repair then you run the risk of forcing it into the water jacket , now there is a hole in it , and restricting the flow.

    If you try and do it in situ then it is not the best environment to try and drill + tap with any degree of accuracy.

    If it was my bike i would remove the head and send it to me who will attempt a repair and remove the remainder of the studs and fit lovely stainless ones with flanged stainless nuts.

    You have nothing to loose apart from a couple of hours work and a few ,expensive, gaskets.

    As it is no good at present it has got to be worth a punt before you purchase another head , if you can get one.

    Kendo
    Take the pieces and build them skywards !

  6. #6
    Join Date
    Jun 2014
    Location
    Norf East
    Posts
    8,062

    Re: First major disaster.

    Phil, If I was using JB weld I would use this - which has been known to fix cracks in the cases of a 1200 bhp CV12 engine so its good stuff.

    http://www.ebay.co.uk/itm/JB-WELD-WO...item3cba661719

    That said, if I could of sent Kenny 6 tonnes of power-pack to repair it would of been no contest and although it means a bit of time away from your latest project I would take the man up on his offer (and they you can have the relaxation of lapping valves etc etc and stem seals are not arse rippingly expensive if you wish to go the whole hog)


    Makes me smile tho that every machinist I know would rather sell his arse at kings cross than acknowledge the use of chemical metals

  7. #7
    Join Date
    Jul 2005
    Location
    Scotland (West of)
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    Re: First major disaster.

    Quote Originally Posted by ZRXNige View Post
    Every machinist I know would rather sell his arse at kings cross than acknowledge the use of chemical metals
    No way i am returning to that profession , it was a complete pain in the arse.

    Kendo
    Take the pieces and build them skywards !

  8. #8
    Join Date
    May 2009
    Location
    Nottingham
    Posts
    3,604

    Re: First major disaster.

    No problems only solutions.
    Let me try the 4.09 one first, nothing to lose. If no joy it'll go to Kendo.

  9. #9
    Join Date
    Jul 2005
    Location
    Cheshire
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    Re: First major disaster.

    How hot do you rekon that area gets. Couldn't you just seal the new stud in with PTFE tape, it has a working temp tolerance up to 500 degrees.

    Or something like this, one of its uses is for sealing through holes........

    http://www.amazon.co.uk/Permatex-592.../dp/B0002UEOP0
    Last edited by phoenix; 19th April 2015 at 05:51 PM.
    Se si muove, sorpassilo. Se non, lucidilo.

  10. #10
    Join Date
    May 2009
    Location
    Nottingham
    Posts
    3,604

    Re: First major disaster.

    Quote Originally Posted by phoenix View Post
    How hot do you rekon that area gets. Couldn't you just seal the new stud in with PTFE tape, it has a working temp tolerance up to 500 degrees
    Interesting. But seems a very harsh environment for PTFE tape.

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