Lock nuts aren't a bad idea, neither are serrated nuts. I lost one nut at about 1200 miles, I replaced it and torqued all the exhaust nuts to 120 lb/in and haven't had a problem with them since. I'm using the standard flanged nuts, no serrations. It's still a good idea to keep a close eye on them though.

 

Jam nuts
Stover nuts/Staked nuts/distorted thread nuts
Stage-8 header nuts
Etc.

 

Instead of loctite use copper anti seez on the threads. It will help prevent gaulding so the nuts can be removed, but it also fills the air gaps in between the threads and works like loctite to keep the nuts from coming loose.

 

In that area, locktite will pretty much heat & do nothing. Re-torque to speck & double-nut them...you'll be good.

 

I am not saying he was wrong, just that in my particular case I use it for piece of mind and I haven't had issue. But yes, proper torque does also mean more than just applying some product.

 

Come on now....

 

Ive been checking the nuts after each heat cycle but the nuts appear to have to much vibration going on. I may not have had them at 120 inch lbs but, I just dont trust torque wrenches, Ive gotten bit too many times by over-torquing with those damn things and getting bit by breaking an exhaust bolt is a risk I didnt want to take. They used to supply nuts with a dimple in it to give resistance to the nut. Now, the nuts spin on with ease and no resistance. Sounds like the simplest idea is to double nut the flange. The simplest solution to a problem is usually the correct one (Ochams razor).

 

Well if the torque wrench has been calibrated properly and has never been dropped or had any damage, torquing shouldn't have ever done that unless the torque was set wrong or there was damage to the bolt. But I can't speak for all instances and torque wrenches, just what I know I learned and used during my time as an aircraft mechanic. Sorry you were having issues.

 

I put on new stainless steel serrated flange nuts I get from ACE Hardware when I pull the pipes. I also follow up with checking the torque regularly...Even before I went to stainless steel, I do not recall ever finding one loose...so far...

 

always torque mine to 11 nm never had problem yet, but have just changed exhaust completely on the Fatbob so will be double nutting, it cant hurt to be safe, also if anyone uses locking nuts, do not forget not the plastic lined ones otherwise they will melt and fall off.