ORIGINAL: Ferocious Frankie

Hi guys,

I got the third flight on my Yak today and for the third time the muffler loosened. On the first time, I used Z-42 blue thread locker. The second time I used Permatex Sleeve Retainer and it loosened again. I was thinking I had not let the retainer properly set, so I took the muffler and cleaned the muffler and threads with acetone. I used the retainer again, letting it properly set, and today for the third time the muffler loosened. This is a Slimline Side-Mounted Pitts on a Saito 1.80. The muffler uses a nut that screws into the engine's exhaust port and that is what is loosening. Mind you, I have tried to tighten that nut as tight as possible each time, but it just keeps loosening despite the thread locker and retainer.

I'm thinking next is red loctite, or silicone gasket maker.

Any suggestions?

Thanks