Head bolt did not torque down

When I took off my heads, one of the head bolts snapped off in the block. It actually felt loose immediately when I began to torque it off, like it was sitting in there loose before I touched it, and sure enough, it was broken. To make a long story short, I resorted to using a heli coil kit (Napa's "head bolt repair kit"). When I torqued the new bolts down on the new heads, the heli-coiled bolt only got to 50 ft/lbs, unlike the 75 ft/lbs needed. After that, it just spun and did not get any tighter. Obviously, this is not good, I want a good reliable car, not one that will blow head gaskets and such.

What are my options here? Do I have to get an entirely new block? Let me know what you think, thanks.

z2o_what said:

you could probally get the hole rethreaded

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Can you elaborate on this?

jrichker said:

If you helicoiled one of the short lower bolts, the helicoil may have spun down into the water jacket. Remove the helicoil and apply some permanent grade Locktite to a new helicoil and install it. Let it harden according to the Locktite package directions prior to installing the head.

On all the short bolts, use teflon pipe dope (hardware store or Home Depot item) on the bolt threads, and anti-seize under the bolt heads. Use lots of anti-seize on the long bolts under the bolt heads and on the threads.

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It was indeed one of the short lower bolts. I used the red high strength loctite and let it cure for over 24 hours. I also used the teflon liquid thread sealer on all of the lower bolts. And I even used anti-seize where the head bushings contact the head (I am using Edelbrock performer heads, so it requires me to use the Edelbrock bushing kit instead of the washers that came with the ARP bolts or whatever). Good to know that I am at least doing some things right. The ARP bolts came with instructions as well, and just said to use 30 weight motor oil on the long bolt threads, and not anti-seize, because it would throw the torque readings off, so I just used the oil on the long bolt threads.


When I initially torqued the bolt to 30, it was getting tighter, and then let loose and spun easily. I knew the heli coil let loose at that point, and just kept turning it. It caught again and torqued to 50 before it started to let go again. I think what happened is I put the heli coil halfway down, and when it initiallly started spinning, it rode up the hole towards the head, and finally ended up butted against the head, where it caught again and was able to torque to 50. However, it started spinning again, which could only mean that the hole ended up slightly larger than it was supposed to be, which is entirely my fault.

So I have already followed the directions, and your advice, to a tee when I initally tried this. Now what?

I am probably going to take it in somewhere to see what a shop says. I am the one that screwed this up, and since my efforts at repair have failed, I should let someone more experienced try to fix my mistakes. Will a shop be able to do anything for me? Or would someone recommend that I try one last thing? It will not be fun to move the car anywhere at this point.

z2o_what said:

if your threads in the block are stripped, you could take it to a machine shop and have them rethead the holes.......or, you could do it yourself if you have the tool

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Alright, so what you are saying is that they can put metal back inside the block?

I take it that because no one is replying, no one wants to be the harbringer of the news that I need a new block.

A member of the local mustang club suggested something interesting to try. Perhaps a head stud is the answer, since it is less of a twisting torque so to speak, and more of an upwards lifting torque. I might give that a shot.