Cylinder bolt problems about to throw it away

Discussion in 'Motorized Bicycle General Discussion' started by Houseworth_t, Feb 22, 2011.

  1. Houseworth_t

    Houseworth_t New Member

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    Breaking in the engine had a sudden loss of power up hill found out exhaust was leaking through head gasket tried to tighten head bolts up while warm with torque wrench to 10ftlbs when one bolt kept turning Crap! taking cylinder off found block threads were stripped or so i thought threaded the bold it with cylinder off it went in fine and got tight seemed fine i put thread lock on too to be sure went to tighten all up and kept turning along with another bolt CRap! now I am frustrated spec is 12 ftlbs im at 10. this thing has cost so much and so many problems out of the box with carburetor clutch throttle assembly chain coil pack and spark assembly everything the other bike went together great what should i do thread it out and helicoil it? I know this is cheap stuff but am i over tightening it? oh and the peddle strippend out and fell off while i was peddle starting any hints there (was probably funny to watch) HELP thanks for your time. this is a grubee 66 kit .bf.
     
    #1 Houseworth_t, Feb 22, 2011
    Last edited: Feb 22, 2011
  2. HT2005

    HT2005 Member

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    Since you've had so many problems with this kit, especially the stripped block, the best thing that you could do is buy another engine. That way you could use your current engine for parts if/once something breaks.

    If the actual plastic pedal stripped off the crank arm then you should wait until you gather enough speed before releasing the clutch to start the engine (try 7-10 m.p.h.). I know that from experience pedaling the engine until it starts will put plenty of stress on the pedal joint.

    P.S. It would help tremendously in the future for you to use proper grammar and punctuation in your writing. Separate thoughts by paragraph as well. Doing so in the future will help us to help you by understanding what you're writing. I had to read your post three times to fully understand it.
     
    #2 HT2005, Feb 24, 2011
    Last edited: Feb 24, 2011
  3. Drewd

    Drewd New Member

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    on your next engine replace studs with better ones and in the process JB weld them into the block. Your issue is very common and this tip solves future problems. I do it on all of my engines.
     
  4. Mac

    Mac New Member

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    A PROPERLY done Heli-coil will work perfectly. Have a machinist do it and you can get the results your dollar, If machining cost becomes a factor, get a new motor, save the old one as parts of sell it to re-coup some $$., forgot to mention, do you have 8mm studs or 6mm studs for your head hardware, 10ftlbs is wwaaay to much or 6mm, OK or 8mm.

    Good luck
    Mac
     
  5. Joey

    Joey New Member

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    i suggest you put a pin into the bolt, solved my problem perfectly..
    i can get you a picture if you want.. but basically, tap a hole in the side of the engine, then just put a pin into it with jb weld :)
     
  6. biknut

    biknut Active Member

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    Installing a helicoil is actually very easy to do. All you need is a propper size drill bit and tap. A thread repaired with a helicoil is stronger than stock.

    Part of your problem could be your torque wrench if it reads in ft lbs. I would use a wrench that reads in in. lbs.
     
  7. biknut

    biknut Active Member

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    After riding about 100 miles be sure and retorque the head bolts.
     
  8. dmb

    dmb Active Member

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    vw's are prone to pull studs they use heli-coils but they call them case savers and work so well that all rebuilds use them and they come in sets of 16. check out the web sites
     
  9. thatsdax

    thatsdax Member

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    I have found that 80 inch pounds is good for M6. 85 max. That is around 6.5 ft lbs of torque. Go to 40 , then 60, then 80 using a criss cross pattern until you get to 80-85 inch pounds. After the 1st hour of riding, check and make sure they are at 80 inch pounds. I have found that even at 100 inch pounds once the engine heats up and everything expands, it can pop the threads in the block. Factory spec is 101 inch pounds, but I have found this to be a little on the high side and at 100 inch pounds under expansion during run in, it can pop the threads. I have had the best of luck at 80-85. Enjoy the ride.
     
  10. dmb

    dmb Active Member

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    a big foot lb on those small studs didn't seem right to me. but you work with what you have. i've built, honda's, motoguzzi's, harleys,sbc's[who hasn't] and even cummin's diesel's and i alway's learn new things except spelling. anyhow i like the small torque wrench with the needle arm, there cheep and don't need calabration, sears husky ect at a yard sale. and snap-on is way over rated, they won't replace worn wrenches
     
  11. mrmpg91

    mrmpg91 New Member

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    thank you for the advice
     
    #11 mrmpg91, Apr 18, 2011
    Last edited: Feb 12, 2017
  12. DaveC

    DaveC Member

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    If your talking about pulling the stud out of the block then there are three things you can do,
    1)JB Weld the stud back in
    2)heli-coil the hole
    3) drill and tap to the next size stud

    Biggest problem is the Chinese often do not tap the holes in the block all the way, cutting costs. What happens then the stud does not go to the bottom of the hole and there's less threads engaged by the stud. You put the acorn nut on and before it can tighten the head down the acorn nut stops threading on and the stud turns, giving a false torque and you pull the stud out of the block.

    ALL the holes need tapped, something most do not do and then wonder why things fail. It's because the Chinese don't care. They know where these things are going and if a motor holds together long enough to be put in a box it's good enough.(yah, cynical, I know :p )
     
  13. heyscuba

    heyscuba New Member

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    heli-coils,... don't know what this means
    to heli-coil a hole,...?
     
  14. heyscuba

    heyscuba New Member

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    when I 1st worked on my motor one stud came out with the acorn nut provided, I had a hard time getting it back in, so I actually ground 2 flat spots on the center of the stud (between the threaded area's) and used a small wrench to tighten it down in there,...
    Probably no the best idea, but it worked and it's not like that bolt is holding up an I beam or anything,...
     
  15. Drewd

    Drewd New Member

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    heyscuba,
    Your best bet due to your level of mechanical knowledge is to take it to a machine shop and if you are lucky, ask them to allow you to watch how they repair your engine. Also, try to find someone locally who is mechanically inclinded and can teach you how to maintain the engines.

    I personally prefer time-sert over helicoils. ++ TIME-SERT Threaded inserts for stripped threads, threaded inserts, thread repair stripped sparkplug's, Ford sparkplug blowouts, threaded inserts threaded, repair stripped threads, stripped threads, inserts threaded inserts, Ford spark plug repair, You can google/youtube timesert and find videos how to use these thread repair products.

    Good luck, there is only so much learning you can get from a forum.
     
  16. heyscuba

    heyscuba New Member

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    thanks drewd,...!
     
  17. GSU

    GSU New Member

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    I have a Gt5 skyhawk and I think that two of my threads stripped out in the holes that go into the head. When I took all four bolts out, the two that would not tighten came out with the acorn nut still on top and aluminum on a few of the threads at the bottom. Just wondering what did yall end up doing to fix this. How much are the helicoils? Can I use the same size again if i helicoil?
     
  18. Drewd

    Drewd New Member

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    Not sure how much helicoils cost because I use Timeserts instead. However, I do know that Harbor Freight carries helicoil clones and I'm sure they are cheaper.

    Do not reuse the OEM studs-they suuck. Get all thread from fastenal (what I usually use) or buy replacements from sickbikeparts.com.

    Please review my tips for newbies. One tip is repalcement and JB welding of the studs so they never loosen causing mistaken tightening up of acorn/headbolt nuts which strips out the partially backed out threads on the block. All of my tips are based of years of uncovering issues with HT engiens and are written to help make your engine bulletproof.
     

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