Helicoiling the valve cover mounting holes

Discussion in 'The Garage' started by gn77b, Jul 27, 2012.

  1. gn77b

    gn77b Been here awhile

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    dang this sucks.
    I made a test blind hole on scrap, tapped it and tested to see what happens if the tang is not broken. what happens is that the screw catches part of the last thread, bends it, and the insert strips the part of the screw.
    #41
  2. Bounder

    Bounder ExternallyDisplaced

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    Thats why I prefer Timeserts.
    #42
  3. corndog67

    corndog67 Banned

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    Is there a flat surface next to and around the hole you're drilling? Make a drill guide, get a piece of aluminum, maybe a 1/2 or 3/4 inches thick, and drill the correct size hole through it, preferably in a drill press, the same size as your heli-coil tap drill. If possible, use a drill press to get it perpendicular. Figure out a way to clamp it to the cylinder head, or just hold it down with your hand, it will help guide the drill in a perpendicular fashion when you drill it. And it will also tend to keep things from wandering around and making that hole 3 times bigger than it should be.

    Clear as mud, right?
    #43
  4. JimVonBaden

    JimVonBaden "Cool" Aid!

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    They both have their benifits and drawbacks. Timeserts require more meat drilled out, cost more, and are not necessarily required or stronger, depending on the circumstances. Doing the job correctly would have prevented this issue.

    Jim :brow
    #44
  5. GreaseMonkey

    GreaseMonkey Preshrunk & Cottony

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    +1 on the timeserts, I suspect that just like in church the people who talk about them the most have not had much experience working with them.

    Also agreed that this is now a RTFM type of issue, and believe me I am qualified to comment on those as well.
    #45
  6. kantuckid

    kantuckid Long timer

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    I am in the camp with the "overthinking the problem" people & not saying that to be critical either.You heard that from a voice of experience which is often worth listening too. Yes , I did this sort of repair as a routine thing(as in for a living) & find the alloy stuff part of my reason for the above comment. As to Helicoils,timeserts, comparisons: there is a reason that there are not only different brands of thread repair items but also different choices with in a brand. I have seen perhaps 6-8 variations and all have their merits. I have used Thinserts & Timeserts often & choose them over helicoils most of the time but not always. This stuff is available in Europe & some made there too. The German inserts are sold on ebay and several other thread repair items there in small #'s/kits for home repairs. There are even "other brands" of Helicoil. The most common issue I find is what insert works with the metal left in the wall thickness or getting the depth I want. At times it is necessary to choose a new size thread over the original damaged one.
    Too bad you are "on the moon":huh where you couldn't just get the originally suggested professional opinion , then go ahead with the fix yourself. My popcorns gone, good luck with the threads.
    #46
  7. Beezer

    Beezer Long timer

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    ". what happens is that the screw catches part of the last thread, bends it, and the insert strips the part of the screw."


    ahhh..... shorter screw? add a washer? :evil
    #47
  8. gn77b

    gn77b Been here awhile

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    you are making assumptions too.
    I am not "on the moon" but finding a place to keep my bike with the engine open whilst I go to have the job done would've been more of a headache than just going to my garage at the countryside and do it myself. not everyone has a garage where they live.
    also, I had finished the job before you posted.
    all went OK except that one of the towers broke when torquing the bolt down. maybe because of a bad torque wrench, maybe because of some oil that went to the threads and caused overtorquing. or maybe I somehow inserted the "spring" a tad too much and it reached the unthreaded end of the hole. not likely since the bolt rotated freehand but who knows. a point to pay extra attention to in the future though, provided I ever get to do a similar job. anyway that was repaired meanwhile and bike is up and running.
    #48
  9. bomber60015

    bomber60015 Anatomically Correct

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    GN

    First, congrats on finishing the job!

    Second, relax a bit ;-}
    #49
  10. gn77b

    gn77b Been here awhile

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    I don't recall typing with caps, bold or multiple exclamation marks that would indicate that I'm tense.

    as seen from my previous post this turned not to be exactly a problem-free job. removing the caps, redrilling and retapping was a piece of pie but somehow that "tower" cracked so the "just go ahead and drill, grind, cut and then weep" approach is not exactly recommended. I'd advise everyone to do similar jobs with extra care.
    #50
  11. bomber60015

    bomber60015 Anatomically Correct

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    GN --- you're correct. Absolutely correct.
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  12. kantuckid

    kantuckid Long timer

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    Thread repairs are something I had the luxury of being trained to do,was paid for learning too & had great teachers from the "greatest generation" who were trained by others before them-point being , that when you're not trained, then it's tough learning on your own machine,over the web,etc..It can be tricky business, fraught with chances to cause expensive damages, esp. when engines are involved.
    To offer a comparison, there is a reason I have always paid someone else to lay my new carpet, not wanting to learn on my dollar, even though it's not that technical. Glad your back in business!
    #52
  13. Anorak

    Anorak Woolf Barnato

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    Timeserts use the same size STI taps as helicoils for the same diameter fastener.
    #53
  14. JimVonBaden

    JimVonBaden "Cool" Aid!

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    If you say so.

    Jim :brow
    #54
  15. Anorak

    Anorak Woolf Barnato

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    Your not familiar with STI?
    #55
  16. gn77b

    gn77b Been here awhile

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    well wrenching is a bit of a hobby. I'm perfectly aware that a lot of things you only properly learn after doing them wrong but I'm up to pay the price. so far I haven't caused any disastrous or expensive damage.
    as for paying the trained person to do it, I can't recall the times when I needed to re-repair the repair done by the professional plumber, just to give an example. or, having seen an improperly torqued rear axle nut causing the wheel to travel towards the rear of the swing arm that it's a wonder the chain did non break, and all that done by "professional" mechanics...
    my sensation is that in the last years there's a tendency towards quantity over quality and that includes trained people.
    #56
  17. kantuckid

    kantuckid Long timer

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    Sounds pretty bleak? Truth be known we are well into several generations of non-professionals that cannot hang a picture on the wall!-all thanks to the move away from teaching basic tool skills & process, was called "industrial Arts " in my day.Same is happening to art,P.E. & music. We still have artists and so forth but some cause me to think they lack talent at times too.:D Used to be the future bankers & doctors,etc. even took some basic shop skills classes, what with many ending up as serious hobbyists too.
    As one that taught people to "fix stuff" I can assure you, there are some pretty darn good ones out there , even today. Why don't you attend a tech competition and see for yourself that skill lives on. Todays' vehicles are designed for throwaway so it's a bit different in many respects(no rebuilding waterpumps for $6,e.g.) but still their are those that want to learn via use of hands & brain in combo. Are there those that are lacking, sure. A friend of mine employs a kid/guy that was a winner in auto body competitions. I'm not so certain that he would score high enough for Ivy people on the ACT but can tell you with certainty that he is a star in the shop! Actually quite an articulate person in the ways that matter in everyday life.
    #57