broke a head bolt!!

[squiblex]

hey was just wondering how bad is it if i broke a head bolt, i tightened up my head bolts on my holden 308 carby motor to almost 70 nm an the number 1 head bolt in the sequence snapped! every thing is already on the motor an i dont have the cash to rip all the gaskets off to re do it all, how bad is it if one bolt is not there?? will the heads worp or will the car run like ****??

 

[acarmody]

I would go talk to a head specialist, but I'd say its back to ripping the heads back off. Tough break mate.

 

[squiblex]

spewin, lucky me lol!!!

 

[bogan_vk]

id be ripping the head back off and hopefully theres still enough of the bolt sticking out to get some vice grips on to remove it shouldnt be too hard to remove.i dont think you really have choice in that situation. you might get away with re-using some of the gaskets all though i would just bite the bullet and buy new ones.

 

[Brett_jjj]

You should run an appropriately sized thread tap through the head bolt holes in the block first to clean out and tidy up the threads. This should always be done first before fitting and tightening the head bolts..This should also be done to any other bolt holes in the block like crankshaft bolt holes, and the timing cover or water pump bolt holes etc..

 

[ari666]

which head bolt btw. and is it actually the head bolt that snapped? the reason i ask is if it snapped at 70NM, then i would be buying a whole new set anyway. seeing as they are meant to be done up to around 100nm, how many others are weakened?

anyway. if its one of the 2 inner valley head bolts, then its not a problem. the casting for the threads is really weak and you should only do those 2 up to the first stage of tightening (50nm) later model heads dont even use them. i was advised by my builder to just delete the threads altogether. i didnt, but just nipped them up to 50 and left them. also if you have actually cracked the casting, make sure you get all the metal out of the valley.

 

[squiblex]

its the middle one on the outside of the head, yea its def snapped! lol an yea theres enough to get grips on there i just have to take it all apart again i recon there all pretty had it any way, plus i think my torque wrench is ####ed too its pretty old an been through the wars lol