View Full Version : head bolt poped on final torque to 90*


3rdCoastPowerSports
04-20-2012, 01:01 AM
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

gregrob
04-20-2012, 02:44 AM
You probably cracked the block...

Did you clean out ALL the water / debris before torquing down the head bolts?

00byrd
04-20-2012, 03:36 AM
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.

baxsom
04-20-2012, 04:12 AM
this right here is the exact reason why lashway is doing my build. i have read too many posts of this exact same thing happening and my luck will put me on the list as well.

Paul Bell
04-20-2012, 07:37 AM
Another good reason to go with studs.

vettenuts
04-20-2012, 07:45 AM
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?

gMAG
04-20-2012, 08:57 AM
It is also possible that the threads were damaged to begin with.

3rdCoastPowerSports
04-20-2012, 10:34 AM
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?

upon further inspection i don't think the hole had been heli-coiled before.
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.

BigBirdLS1
04-20-2012, 10:58 AM
If you want to fix it correctly an not EVER worry again a Time Sert is your answer.

3rdCoastPowerSports
04-20-2012, 11:33 AM
I know for a fact that this block has had the heads R&R maybe 7 times over the course of its 10 year life span. could this be why the threads tore out?

The holes were properly cleaned, chased and dried before the bolts went in

S10xGN
04-20-2012, 08:10 PM
Another good reason to go with studs.

Times 10^3! ;)

badazz81z28
04-20-2012, 10:25 PM
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.

BigRich954RR
04-20-2012, 10:51 PM
I know for a fact that this block has had the heads R&R maybe 7 times over the course of its 10 year life span. could this be why the threads tore out?

The holes were properly cleaned, chased and dried before the bolts went in

YES alum threads wear as you RR the bolts so might be the cause . big reason racers also go with studs

Burken01
04-21-2012, 02:08 AM
got any pics??? you might be able to put studs in and save the block if the damage is slight>>

01ssreda4
04-21-2012, 02:23 AM
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.

3rdCoastPowerSports
04-21-2012, 01:28 PM
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.

yeah the sound sucks... as soon as i head the loud pop i just put my shit down, went inside and had a few beers before investigating what the pop was. I just bought the kent moore time sert kit J-42385-100 & 300. set me back about $350 bucks,,, but damn it looks badass.
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 :judge:

92slomaro
04-21-2012, 08:42 PM
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 shit 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!!

SF 1HOTLS1
04-21-2012, 10:21 PM
If you want to fix it correctly an not EVER worry again a Time Sert is your answer.

Whats a time sert? i googled it and kinda looks like a helicoil

3rdCoastPowerSports
04-21-2012, 10:37 PM
http://www.denlorstools.com/autoblog/2011/09/time-sert-vs-heli-coil-whats-the-difference/

SF 1HOTLS1
04-21-2012, 10:39 PM
thanks!

3rdCoastPowerSports
04-21-2012, 10:41 PM
no problem. Time sert is bad fucken ass man. just expensive to purchase

vettenuts
04-22-2012, 08:38 AM
I think you are taking the right approach. A long thread like those in the block are more highly loaded near the top. Because bolts have been used so many times along with the load distribution in the upper part of the threads it is not surprising that the upper threads have failed.

Good luck going forward.