I cannot seem to get a nut to torque on one of my exhaust manifold studs. I can get the nut hand tight, but when I start using a torque wrench it just spins. When I take it off I can see that the stud has backed out of the engine block some. I then re-install the stud using the double-nut method and get it as tight as I can until the nuts on the stud spin (meaning the stud has been torqued into the block). Then when I re-install the turbos manifold and put on a copper lock nut and try to torque it down to even 20 FT-LBS, it just spins.

What is going on? What can I do to get this to torque down?

 

what are you torquing the studs down to? it almost sounds like the threads on the housing are stripped.

 

10 ftlb

 

I did more inspection on the hole, it does appear to be stripped.

What's the success rate of using a helicoil there?

 

I have used helicoils for lots of things and they hold up good. I have one in my housing but I have not tested it as of yet.
Thanks

 

Helicoil saved the day. Let's hope it lasts through the heat.

 

Let me know how well it holds up.