Muffler keeps coming loose
 

I have a U.S. 41CC engine I put on a Stinger. It flys great, but the muffler keeps coming loose. I tried the blue locktite, then the red locktite, no luck. After 30 minutes of flying, the muffler is loose again. I have tried 4 times now. I have cleaned everything before applying the locktite.I also use locking washers. I have used the stock gasket, and without. I am using a GP isolation mount, and have to be able to remove the muffler to use the mount. I am thinking of buying a b&b muffler, to replace the stock one. I am guessing the muffler might be damaged (crushed) where the bolts tighten. If anyone has any idea's how to stop this, please post or email me.

RE: Muffler keeps coming loose
 

I've had good luck using high temp never-sieze on my exhaust systems. I use the silver type.

RE: Muffler keeps coming loose
 

Find someone who knows how to safety wire. I think harley riders do a lot of it and its done on full scale aircraft. Safety wired bolts done correctly are physically impossible to have come loose.
Al

RE: Muffler keeps coming loose
 

This is a problem with a lot of gassers depending on the muffler type. If the bolts are crushing the muffler it is doubtful that wiring the bolts heads will help. Use large, thick steel washers or a piece of steel plate to stop the crushing potential. Not sure if your particular muffler has any supporting straps on the far end but this is what a lot of muffler types need to prevent them from shaking loose, particularly Pitts mufflers.

RE: Muffler keeps coming loose
 

Safety wire the bolts to each other or around the engine/muffler. Even if the bolts do loosen, there is nowhere for them to go. This will end your problems. I do this on all my engines right away and have never had another problem.

RE: Muffler keeps coming loose
 

Lose the isolation mount, use loctite & large washers.

RE: Muffler keeps coming loose
 

Not necessarily. Depends on what is causing the problem. If the bolts are getting loose due to the muffler crushing at the bolt locations the wire will keep them from backing out completely but may not stop them from getting loose. The problem is not the bolts falling out. All it takes is a very slight amount of movement for them to get loose enough to cause the muffler to rattle. Once this starts, it can deteriorate the gasket (if there is one) and cause RF interference.

RE: Muffler keeps coming loose
 

Try a dab of high temp gasket silicone on the screws. Let them cure completely and they should stay. Personally I use red loctite and have never had one come loose. I am thinking the isolation mount is causing your problem. I have heard that muffler flanges can break with isolation mounts.