WARNING! Firesleeve throttle and mixture controls.

[Captain Mike]

WARNING! Firesleeve throttle and mixture controls! Ask me how I know. With appx 300 hours on my first RV-8 the throttle and mixture cables (Van's green type)became very difficult to move. The cables were not close, in my opinion, to any heat source, ie the exhaust pipes. Closest was 5.5 inches but never the less locked up over time. Both cables are now removed from aircraft to be replaced with new and FIRESLEEVED all the way to firewall. The removed cables cannot be moved at all by hand but have no external damage.
Hard way to learn this lesson as those cables including throttle quadrant had to be removed from completed aircraft to replace with new.
Mike Ballard
Building RV number 4
Flying RV-8 number 2
Sold RV-8 number 1 & RV-6A

[dan]

I used reflective heat tape on my throttle cable instead of firesleeve. My theory was -- firesleeve will resist flame, but may not "reflect" typical radiant heat as well as other things can. But I totally agree with you in principle about doing your best to keep heat away from those cables.

[frankh]

How about using auto store fuel hose slit down the side for insulation covered in reflective tape?

Frank

[Mike S]

Go look for a thread by Paul Dye about a similar problem, turns out the actual cause was electrical-------throttle cable provided a ground path.

Do you have a ground strap from the engine to the firewall???? Or at least back to the mount on the other side of the rubber mounts??

I have had the same problem in VWs, and Porsches.

[Ironflight]

Originally Posted by Mike S

Go look for a thread by Paul Dye about a similar problem, turns out the actual cause was electrical-------throttle cable provided a ground path.

Do you have a ground strap from the engine to the firewall???? Or at least back to the mount on the other side of the rubber mounts??

I have had the same problem in VWs, and Porsches.

In the interest of keeping the record straight, I never made that determination Mike. What I DID find was an area of discoloration right at the point where the cable was stiff, and the inner diameter had shrunk to where it bound on the moving core. This was directly over the exhaust pipe spreader - there was a part of the cable closer to the pipes that was not constricted. The discoloration looked like chlorine corrosion, although I don't really think that is what it was. I never came up with a good cause, but did replace both mixture and throttle eventually, and agree that insulation of some sort is a good idea - can't hurt! (I have several ground straps that are carrying the engine load, so I don't think it could have been that.)

Changing the cable at the quadrant is a horrible pain,....but easier the second time around!

Paul

[Flyrod]

Hey, funny this thread came up today as I just came from NAPA and picked up about $100.00 worth of heat mediation gear. If you look at their performance catalog, there is a company that specializes in heat mediation and control materials. The control cables are one of my targets as well as the fuel pump. I also picked up some exhaust wrap to help pump more heat out the cowling. Ordered a 90 degree elbow from Vans with tubing to get heat muff hot air out of the cowling when cabin heat is shut off which is most of the time here in Florida.

[Mike S]

Originally Posted by Ironflight

In the interest of keeping the record straight, I never made that determination Mike. What I DID find was an area of discoloration right at the point where the cable was stiff, and the inner diameter had shrunk to where it bound on the moving core. This was directly over the exhaust pipe spreader - there was a part of the cable closer to the pipes that was not constricted. The discoloration looked like chlorine corrosion, although I don't really think that is what it was. I never came up with a good cause, but did replace both mixture and throttle eventually, and agree that insulation of some sort is a good idea - can't hurt! (I have several ground straps that are carrying the engine load, so I don't think it could have been that.)

Changing the cable at the quadrant is a horrible pain,....but easier the second time around!

Paul

Paul, sorry, my mistake.

My poor old brain just aint up to remembering as well as it used to.

Anyway, I looked up the original thread about your cable---mixture---and the comment that I remembered about the ground problem was by "Monkey".

However, a bad ground can cause this type of problem.

Right thread, wrong post.