head bolt poped on final torque to 90*
04-20-2012, 12:01 AM
#1
head bolt poped on final torque to 90* i was torquing the center m11 head bolt to its final 90*, at probably 80* i heard a loud pop. as soon as i heard the pop the bolt turned alot easier but still took slight effort to turn. i backed the bolt out to investigate. two threads on the bolt have aluminum stuck in them so im guessing the bolt pulled out the threads in the aluminum block.
but why only 2 winds of aluminum on the bolt i pulled out? if it stripped the block and pulled out the alum block threads shouldn't there be alot more aluminum stuck on the bolt. did i maybe pull out a old helicoil repair? any insite is appreciated...
if the bolt looks like this [|---=======
............................right here^ is where the aluminum is stuck in the threads of the bolt
but why only 2 winds of aluminum on the bolt i pulled out? if it stripped the block and pulled out the alum block threads shouldn't there be alot more aluminum stuck on the bolt. did i maybe pull out a old helicoil repair? any insite is appreciated...
if the bolt looks like this [|---=======
............................right here^ is where the aluminum is stuck in the threads of the bolt
Last edited by 3rdCoastPowerSports; 04-20-2012 at 12:40 AM.
04-20-2012, 02:36 AM
#3
Make sure all water is out of the bolt holes...I used a straw and taped it to my shop vac. and then used paper towels to make sure it was dry. Also check your torque wrench, I broke a ARP bolt on time because of this. No sicker feeling. Btw drilled mine out and fixed with a helicoil from autozone,held fine.
04-20-2012, 06:45 AM
#6
Couple of questions, you mention a heli-coil, has the block already had a thread repair? If yes, do you know the "D" of the heli-coil that was used? ("D" is a measure of length by bolt diameters).
When a bolt loads internal threads, the upper threads take more load than lower threads. When you removed the bolt, did you back it out by turning counter clockwise or did it simple pull straight out?
When a bolt loads internal threads, the upper threads take more load than lower threads. When you removed the bolt, did you back it out by turning counter clockwise or did it simple pull straight out?
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04-20-2012, 09:34 AM
#8
Couple of questions, you mention a heli-coil, has the block already had a thread repair? If yes, do you know the "D" of the heli-coil that was used? ("D" is a measure of length by bolt diameters).
When a bolt loads internal threads, the upper threads take more load than lower threads. When you removed the bolt, did you back it out by turning counter clockwise or did it simple pull straight out?
When a bolt loads internal threads, the upper threads take more load than lower threads. When you removed the bolt, did you back it out by turning counter clockwise or did it simple pull straight out?
When i removed the bolt I had to back it out, it would not pull out. in fact after i heard the pop you could still tighten the bolt more until it would no longer tighten. before the pop it felt like normal, then i heard the pop and the bolt felt more slacked but still felt like it had alot of threads left. the pop just ripped out the top two block threads. if i shine a flashlight down the hole i can see the threads that tore off.
GregRob the block is not cracked, there was no coolant in the bolt hole, the hole was chased and blown out. block is on a stand after i got it back from the machine shop (motor was never filled with fluids or started). i already had a fresh set of heads bolted up but decided to tear them off and go with some ported 243's before installing the motor. I used new bolts for both sets of heads. first set bolted up great.
I was planning on using a time sert to fix the threads. kinda expensive though.
Last edited by 3rdCoastPowerSports; 04-20-2012 at 10:33 AM.
04-20-2012, 09:25 PM
#12
Dude sometimes they can just go. It sucks, Its aluminum and soft. I have stripped my fair share of threaded holes... Threads can be trashed and still allow a bolt to thread in and not pull out, but once you apply torque, it will let go.
04-21-2012, 01:23 AM
#15
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This is a sick sound to hear. Same thing happened to me. I bought a Kent Moore kit, repaired the one hole, sold the kit, and changed to ARP studs (because i'm paranoid). So far so good, and good thing because I've had the heads off several times since.
04-21-2012, 12:28 PM
#16
looks like im all about the studs now... Im pretty sure this is the last build i will use head bolts on... saving money always cost more money
04-21-2012, 07:42 PM
#17
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I had this happen on my friends 02 camaro when we put the heads back on. I asked him if he clean the holes and he said he did. i put the bolts in and when the first popped, i pulled the bolt back out it had coolant on it. i did what someone else on here said and sucked the water out with a straw and vac. after that the bolts went in fine. i cleaned mine out with a vac and everyone i have done since. no problems. just better prep work. the sound scared the **** out of me, i just stared at the engine for a mintue, nervous to pull the bolt out. felt sick to my stomach, lol. simple fix though for me. good luck!!
04-21-2012, 09:21 PM
#18
