Snapped head bolt PLEASE HELP!!

brendonv

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11:24 PM
Joined
May 18, 2008
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286
Location
Perth, Australia
Man i new i shouldnt of touched it but i did, my head was loose and wen i pedaled it made a hiss sound. I tried to tighten the bolts ( not with a torque wrench ) to see if i could close the gap, then im tightening the bolt more and there goes a bang, the top of the bolt gone. Snapped off, what do i do im freaking out, i just got my engine as a birthday pressie, i loved it, just tightening all the screws and things, try tighten the head bolts and bang it snaps. There is still a bit of thread sticking out if i take the head off so lets hope i can take it out with some pliers. Im also freaking out because if i tightened it that tight i may have stripped some thread inside. OMG im so scared, i just want to ride it. Why did i do that man, i hope i can fix it by buying a new bolt. Please tell me how to fix it. I heard people change all the head bolts to high tensile ones anyway so maybe they were **** quality bolts, if i get it out then ill change em all around if thats the case i just need some1 to tell me its fixable and i didnt just f*** up the engine, please help.
 
Scroll down to the bottom of the page & refer to Similar Threads.If unsuccessful there do a search.....i know it's a hassle but it's a good way to learn.
 
I have two options, first take the whole head off, cut a slit in the thread and use a flat head to remove. Second option is buy a removal kit like ezy out i think there called but thats the more expensive option. Then since im taking it all off it gives me a reason to change all head bolts to high tensile (stronger) ones. My only worry is will i need to get a new gasket? Ive only been riding the thing for about 60-80mins all up, do i need a new top gasket? The bottom one should be fine but i heard once the metal one has been compressed you shouldnt reuse it or ur creating more problems than your fixing. Any things i should do while the head is off? Should i locktite the head bolts in or oil them or anything? Anything i should do while its all opened up. I think i no why it snapped, i didnt tighten them the second time in a criss cross fashion i just tightened one wen the one on the other side also needed tightening so i was tightening it while it was on a slight angle which i think is why it snapped. The snap is on a slight angle so i think that was my problem. When i tighten them again ill tighten them like this: 4ft/ lb, 8ft/lb 12 ft/lb and in a X pattern.
 
Take the head off, get a pair of mole grips (vice grips in the USA), grip the threads and screw them out. You might aswell replace all of them. Jam two nuts into each other to screw the new studs in, I use loctite blue that way they can be replaced easily, if you use anything stronger you may have to heat up the stud should you ever need to replace it again.

BTW: I always cut up M6 allthread to replace studs, i woulnd't bother buying a new stud from a vendor.

BSA
 
but mine are like a full bolt, cant i buy long M6 bolts to fit? getting a thread screwed in there then putting a nut on top seems hard.
 
but mine are like a full bolt, cant i buy long M6 bolts to fit? getting a thread screwed in there then putting a nut on top seems hard.
It's not difficult, if you did use a bolt it would have to be Exacltly the right length, better of using thread and nut.

BSA
 
so locktite the thread in then locktite the nuts on then cut of the excess thread then start torquing.
yes, but if you can make the new studs about the same length as the old one, that way you don't have to cut of excess with the head on (which is awkward)
Don't forget to use beefy nuts, perhaps reuse the old domed nuts.

BSA
 
Buy or borrow a torque wrench too. 10-12 ft-lb is not a lot of force, but that's all you need. Remember that when the engine warms up, the head and cylinder will expand a little, making the actual torque higher. I set the torque wrench to 4ft/lb, tighten in an X pattern, then 9ft/lb, then 12ft/lb. On one engine, I found that the acorn nut was bottomed out but the stud was loose. On all of my builds, I have replaced the acorn nuts with metric nuts and copper crush washers. I have kept the stock studs, and made sure they were threaded all the way into the crankcase and used thread locker on all the hardware.

Good Luck
 
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