Broken Exhaust Springs?

Springs can break for a couple of reasons. First the safety wire isn't to prevent vibration. That is there to keep the spring in the plane and not fall off onto a runway or taxiway if it does break. You should be applying high temp silicone to the springs to help dampen the vibration or actually the exhaust pulsation. You shouldn't fill the spring with the silicone like Vans does because it reatins too much heat. The air around a normal springs allows for some cooling and for the spring to give up some of that heat and not retain it. The silicone should be applied to the outside coils and worked inbetween the coils. A pencil then line isn't good enough because it doesn't have enouigh body. I usually apply it at about 3/8" wide to and about 1/4" thick. This gives it some strength. Put the safety wire down through the center. It isn't meant to be tight and hold the system together. That's what the spring is for. I see your safety wire was wrapped around the middle of the spring. If the sprin breaks just above or below the safety wire then that half fals on the runway. Down through the middle keeps the spring right there no matter where it breaks. I prefer to use .041 safety wire. I've seen a hundred of the .032 wire break. Plus some probably over tightened it. Having the proper tension is key. Not too little and not too much. Too little doesn't keep the muffler joint solidly together and allows exhaust leaks  and too much breaks springs.

The other thing that breaks springs is over stretching. Usually about a 1mm space inbetween the spring coils. That's about the thickness of your thumbnail +/-. You could use a feeler gauge if need be. 

There are two types of springs that you'll see. Some stainless steel ones and just a metal one that has less tension.

So the take away is:

use the silicone and don't fill it down the center.

Don't over stretch them

safety wire down the center for better retension if they do break.

My A & P guy agrees with you Roger. I'm redoing spring wiring today.