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Head bolt hole repairs

Posted: Tue Nov 17, 2009 6:34 am
by IronMonkeyL255
Anyone stripped out a head bolt hole in the block before? I managed to do just that working on my car this week (See here for details of my incredibly shitty luck).

What is the best way to repair the threads so this won't happen again?

I thought about drilling it out to the next biggest size for the head stud, but ARP said the next size up is 14mm. That is a bit more material than I am comfortable removing.

I was looking around online, and it seems that Heli-coil does not have anything available in the correct threading for our head bolts (M11x1.25).

A company out of Australia called Recoil has a similar product, and has the correct thread pitch available. The only thing that worries me is that the inserts only have 7-8 threads, and i am concerned that would only lead to more issues down the road.

The most promising thing I have found the the Time-Sert insert kit. It is available in the correct threading, is 28mm long, but is not a wire-type insert like the others.

Has anyone had to repair this damage before? If so, what did you use and how has it held up?[/url]

Posted: Tue Nov 17, 2009 7:10 am
by PhyrraM
I've been lucky enough to not need any thread repairs on my cars.

But, being an industrial maintenance manager for a living....

I HATE HELI-COILS!

They are harder to install, and unless meticulously cared for not very amenable to frequent bolt removal and re-installation.


As long as the ridge on the top of the Time-Sert doesn't interfere with having to install them down in a hole, the Time-Serts are a better, longer lasting product.

There are also other types of inserts that don't need special taps. I would browse www.McMaster.com and see what you come up with.

Posted: Fri Nov 20, 2009 6:18 pm
by IronMonkeyL255
I ordered the time-sert kit. A bit pricey at $400, but it seems like the best solution given the options i have.

Posted: Wed Nov 25, 2009 3:44 am
by IronMonkeyL255
Well, the time-sert went went in alright. I will see how it holds once i get the new studs in and get it all put back together.

Posted: Thu Nov 26, 2009 8:15 pm
by 206er
dang, that is hardcore. i take it was an ej22t otherwise you wouldnt bother to repair?

Posted: Fri Nov 27, 2009 9:10 am
by IronMonkeyL255
Exactly. And these cars weren't too terribly common in this part of the US. I have seen a grand total of 1 other SS/TW in recent memory. I got really lucky being able to get my hands on the 1 other engine in the area, never mind trying to find ANOTHER one.


Good news is now i got the stuff to repair other blocks if someone needs.