a65 exhaust stack failure

[KCOI7]

Curiousm how common are exhaust stack failures?

One of mine cracked - 15 hours after a 50 hour SB inspection.

Also, any thoughts on uding no-blo gaskets versus the thin metal ones?

[Paul Agaliotis]

They happen pretty regular. Grab the stack on preflight and wiggle it, should be no crunching noise. There is an early AD on this problem. Go to the stainless stack and you should be good, no AD on them. Stay away from Wag-Errors stuff, they break quite often. The no-blo gaskets are good but pretty large and fit can be a problem, the copper/asbestos work good with the brass exhaust nuts. The stainless shim gaskets will work but need to be installed correctly. They need to be used in pairs and the beads in the gasket need to be positioned correctly. What ever you use, put the same gasket in all locations. It will keep from loading the header stack and causing rapid cracking.

Paul

[KCOI7]

<<<<<<<<<<<<<<< Go to the stainless stack and you should be good, no AD on them.>>>>>>>>>>>>>>
I thouhgt the AD did not offer any relieve for going stainless, even though the stainless work a lot beter




<<<<Stay away from Wag-Errors stuff, they break quite often>>>
Who else makes them?


<<<. The no-blo gaskets are good but pretty large and fit can be a problem, the copper/asbestos work good with the brass exhaust nuts.>>>>
are you indicating that "copper/asbestos" is a different product )from no-blo?


<<<<<The stainless shim gaskets will work but need to be installed correctly. They need to be used in pairs and the beads in the gasket need to be positioned correctly. >>>>
I was wondering about the proper orientation - thinking 2 per exhaust port, top gasket - ridge up, bottom gasket -ridge down. Is that good?

Thanks - Danny

[Paul Agaliotis]

The Service Help and Hints #25 covers this.

Check with the aerospace welding shops and Univair.

Copper asbestos gaskets come in the overhaul gasket kit. Check with Fresno.

The beading should nest together, two per cylinder.

Paul

[KCOI7]

<<<,Copper asbestos gaskets>>>

I got the no blo wspiral wounds. Had to trim a little to fit- interference with adjoining cylinder

Curious about the coppers ... saw a blurry pic on Fresno's webpage/

Are these thin like the steel ones with the ridge that crushes on installation (and leak)?

[Paul Agaliotis]

The copper are the set I like to use. The stainless shim gaskets will leak if you install them improperly.

Paul