Heat Muff Clamp Wanted

[mikerice]

I have a stock Taylorcraft exhaust with the aluminum heat muff running under the mags across the back of the engine.

Our clamps that hold the heat muff together are looking poorly. I would like a couple new clamps to replace the old ones.

Anyone have any clamps they are willing to part with? I'll go the SS hose clamp route if I have to, but would prefer the softer aluminum clamps.

[Hank Jarrett]

Re: Heat Muff Clamp Wanted

SS Hose clamps will eat into the shroud. Do you have access to a wood laith? If you turn a disc shape into the end of a block you could form a soft aluminum clamp like the original that would wear out instead of destroying the shroud. It would be a lot less expensive to make clamps than a shroud. I would also bet there are a BUNCH of guys who have used SS in the past who would want aluminum clamps.

Hank

The aluminum of the shroud IS weldable and can be repaired, but practice A LOT on scrap first!

[Hank Jarrett]

Re: Heat Muff Clamp Wanted

SS Hose clamps will eat into the shroud. Do you have access to a wood laith? If you turn a round edge disc shape into the end of a block you could form a soft aluminum clamp like the original that would wear out instead of destroying the shroud. It would be a lot less expensive to make clamps than a shroud. I would also bet there are a BUNCH of guys who have used SS in the past who would want aluminum clamps.

Hank

The aluminum of the shroud IS weldable and can be repaired, but practice A LOT on scrap first!

[PA1195]

Re: Heat Muff Clamp Wanted

Maybe put a replaceable sacrificial layer of aluminum between the SS clamp and shroud. Did that on Pipers and it helped spread the clamping force and stopped wear of the shroud.

Gary

[Hank Jarrett]

Re: Heat Muff Clamp Wanted

That is actually a pretty good idea. It would be easier and I would probably take the clamps off at annual and inspect. If the aluminum was showing wear, just put a new piece in. Probably could make the sacrificial part from the bottom of a Turkey pan!

[3Dreaming]

Re: Heat Muff Clamp Wanted

If I needed them I would make them. The middle ones are just a flat strap IIRC. The end clamps have a bead, but still fairly easy to make.

[Hank Jarrett]

Re: Heat Muff Clamp Wanted

Talked to my IA and he said the idea of a sacrificial soft aluminum piece under the clamp shouldn't be a problem at all. Might consider putting it in even with the original clamps.
I still think it wouldn't be very hard to make the correct clamps.

Hank

[PA1195]

Re: Heat Muff Clamp Wanted

Not sure Hank what your shrouds and clamps look like. On one Cub someone had tig welded heavy aluminum doublers over the shroud where the SS clamps went. But then the shroud became a clam that refused to give up its pearls and cracks formed adjacent to the doubler's welds due to stress of periodic opening for the muffler inspection AD. So I replaced the 1954's shroud and had the removable doublers installed.

They also wear internally where the aluminum frets on the metal muffler flanges. One annual fix was and is to apply Permatex Ultra Copper RTV to that surface and let it cure after shroud installation. Once set it offers a lubrication interface that will eventually wear away and needs replacing but that's better than aluminum, especially if it's made of Ancient Unobtanium. That RTV stuff is amazing. I use it on motorcycle muffler to header slip-on connections and it lasts very well under heat providing it remains clamped and doesn't rattle about. Local mechanics use it on aircraft exhaust gaskets to reduce blow by until the header facing area on the heads can be properly resurfaced.

Gary

[mikerice]

Re: Heat Muff Clamp Wanted

If I needed them I would make them. The middle ones are just a flat strap IIRC. The end clamps have a bead, but still fairly easy to make.

I need the end clamps with a bead. Hanks idea of turning a form is a good one. I'll try that route. Thanks for the suggestions.

[Hank Jarrett]

Re: Heat Muff Clamp Wanted

Gary, we were thinking of a piece of "turkey pan aluminum" on the steel inside as well as a wrap around the outside. Steel is just a really bad idea against soft aluminum. Especially with high vibration! The exhaust design on the Taylorcraft never was very good. If it was done again the heat shroud should be completely redesigned and the exhaust itself should really be redone so it could come apart and you didn't have to pull the engine to get the exhaust off!

[PA1195]

Re: Heat Muff Clamp Wanted

The double layer to protect the shroud would be good. They are very expensive to manufacture (duct adapter welding and so on). In some Cubs there's a middle ring on the header pipe so sticking an aluminum one over it and under the shroud would be problematic. That Ultra Copper RTV will hold like glue to whatever it's applied to once set up overnight should someone want to put a layer of aluminum inside the shroud. It also seals any end leaks. It does give off brief smell on first heating: https://www.permatex.com/products/ga...-gasket-maker/

There's also SO (not sure that's the name) soft aluminum available at metal supply, plumbing, and hardware stores in sheets. Not as tempered as the shroud (maybe).

Gary