Exhaust bolts

[CDenton]

My exhaust manifold bolt keep backing out. Had mechanic redo them all and I believe he stripped the threads out on the number one cylinder. I can tighten it but it never “really” gets tight. If I remove the bolt and run a tap down thru it, I need to know what suggestion is the best way to keep it tight in the head, I do not want to use Locktite or know if that would work anyway. During travel had to have another mechanic look at it, he redid it again, new gasket, and it is coming loose again. I do tow with it. Any help is great.

 

[lpennock]

If bolt was stripped you may need to helicoil the hole.

 

[CDenton]

I never used them before. I guess they come in different sizes? Is there any tricks I should know about using them? Thanks

 

[lpennock]

They are pretty easy to use. Clean the crap out of the hole after each step of drilling, and tapping before inserting. Having a bottoming drill helps some but as long as you get enough depth for the coil it isn't required. Other than that it is just like tapping a hole.

PS, they are usually stronger than the metal they are in so your tread strength increases massively.

 

[Ozymandias]

If bolt was stripped you may need to helicoil the hole.

Jep, Helicoli is the #1 Solution for stripped threads.

https://www.ebay.com/bhp/helicoil-kit

And be careful, a Helicoil can only be turned IN and never again turned OUT, it is self locking once inserted.