Exhaust Spring tension and wear

[Roger Lee]

Not having enough exhaust spring tension can cause problems. I told FD 4 years ago they didn't have enough exhaust spring tension. This is one big contributor to the exhaust leaks around the exhaust knuckle just on top of the muffler. The coils are too lax and some have no tension on them at all. There should be a slight bit of daylight between spring coils. I like to see at least a finger nail clearance between coils. Then you must add enough RTV silicone and work it between the coils and make it about 1/2" wide and 1/4" thick to make enough support strength to dampen the exhaust pulsation and vibration. Adding a little thin narrow bead isn't going to do you any good.

 

Here are some pictures of what happens if the spring tension is too light. This has happened to several people and can happen in less than 400 hrs.

 

The spring in the picture shows excessive wear from the vibration and the female receptacle on the muffler has been cracked in 4 places and actually a hole broken out. The exhaust pulsation just beat on the female joint.

 

To apply a little more tension just remove the safety wire, leave the spring in place. Take a steel rod and place it on top of the spring tension loop and smack it with a hammer and spread the gap to tighten the spring. Then re-apply the safety wire. Don't use the .032 use the.041. The .032 breaks to often. Don't make the safety wire tight it should be a little loose. It is only there to hold the spring from coming off the plane in case it breaks or comes loose.