Sonex-A purchase - What to look for

[Area 51%]

Also, one spring that connects the two sections of the exhaust on one side is stretched nice and tight, and the other one is much less tight. Is this an issue? Also, the previous owner ran safety wire down the middle of the exhaust pipe connector springs. Is this necessary?

I personally believe it a necessary add-on. Springs can lose their tension when they get hot allowing the pipes to separate and vent exhaust gases directly on the injector/carb. I experienced such a failure that caused total vaper-lock with a resulting uneventful emergency landing.
At the very least, if you wrap the pipes, keep the springs on the outside of the wrap.

[BRS]

I used to fly a gyroplane, think pusher propeller. The exhaust had about six springs which did a real job when going through the propeller. Wire through the springs were a must. The other thing we did was to run a generous bead of high temp silicone across the stretched springs. Gotta do what you gotta do. In the Sonex I guess it's more about not torching things under the cowl as it's not so likely a runaway spring is going forward.

[Hambone]

Thanks for the replies. I'll run safety wire in the middle of the springs. It can't hurt, and could possibly help.

[bvolcko38]

Add some red RTV to the springs...it keeps them from vibrating causing metal fatigue.