Melted Firesleeve near Exhaust

[mike3715]

I recently had to remove the exhaust from my RV-7 to pull cyllinders, and noticed some melted firesleeve around one of the control cables:

Photos

I removed the firesleeve and noted some charring on the metal sheath, but it appears OK otherwise.

Any recommendations as to how to proceed?

[Kyle Boatright]

Make or buy something like this to clamp to the outside of the firesleeve.

https://shop.vansaircraft.com/cgi-bi...t=heat-shields

It'll block the radiant heat and provide a protected air gap between the exhaust and the cable.

[Scott Hersha]

I also have (had) an AWI exhaust, and had a similar control cable situation. I used firesleeve like you did, but also used the exhaust heat shield like Kyle recommends. That worked for me. I used one on my throttle cable and also the mixture cable going to my Avstar fuel injection servo.

[mike3715]

Thanks!

Is there a straightforward way to put on a new firesleeve without removing the cable?

[Scott Hersha]

Split the firesleeve and just wrap it around. Use safety wire wrap to hold it in place. You might be able to use some silicone tape, but that may melt if it?s not the right kind. Firesleeve is basically a ceramic batting wrapped in a silicone type sleeve - I think anyway....

[BillL]

I have RV7 with AWI and mine is not that close. I have IO360 with horizontal servo. I did stick a thermocouple in the sleeve and measured temps well below the limit given by McFarlane . Tested at peak EGT's, then I added some foil wrap. Not much room for a standard heat shield on mine. it absolutely can not touch the exhaust.

I don't know any proper way but to release the engine end of the cable. I had to do that as the sleeve was shorter than I was comfortable with, resulting in replacement.

BTW - like your hanger.

One more thing - I found I needed some shielding on the underside of the skin, firewall aft, to prevent heating of the FW and fuel in my tunnel. Did you or AWI add the center exit for the breather? I want to clean up that for mine.

[DanH]

Looks like a Sky Dynamics pipe.

Reflective tape is your friend.

[TS Flightlines]

Guys----firesleeve is rated at 450*-500*. If you lay it on hot exhaust and it is allow to cook----it will fail. Whether its a hose, or a throttle cable, its still a bad deal.
If things are that close----put a stainless shield between the exhaust and the firesleeve, or re-route things.
Be careful.

Tom

[BillL]

Originally Posted by DanH

Looks like a Sky Dynamics pipe.
.

Ahh, yes. .

[snopercod]

This stuff works well: Thermo-Flex