exhaust header insulation wrap

[dougmiller]

i've wrapped my headers with insulation, but unique users report that this will dramatically reduce the life of headers. i read the previous posts in this forum and still have no clear opinion of the truth.

one thing that made sense was that it wasn't the rust factor but the heat cycle that will cause the pipes to fail.

can you add any data to this subject. building a unique 289 fia, with a stroker 351 W

thanks

doug

[dougmiller]

further information, i've had the headers and side pipes cermanic coated,

[Robert T. Faust]

Hi Doug,
I had my pipes wrapped for 6 years, and there was no problems (metal deterioration/rotting/rust/etc.) with them when I removed the wrapping last year and had them ceramic coated. I removed the wrapping on account of all the horror stories about gas leaks and the wrapping acting as a sponge, and then fires. It never happened to me but if it could happen,?????? I had the pipes ceramic coated and in my opinion it's better then the wrapping. You can now almost touch them soon after shutting the engine down as the silver (was advised that the silver cooled faster the black coating) ceramic coating seems to have a faster heat reduction.
However, I must say " the wrapped pipes looked more "Senor Lloyd Bridges El Mui Macho"!
Bob Faust

[Mr.Fixit]

I have seen header primary tubes get a hole blown in them from header wrap. Right where the primary tube turns down just outside the exhaust port. (not on a cobra though)

[cobrajeff]

Have had my headers wrapped from day one - no problems after 7 years of use.

I had my headers custom fabricated out of stainless steel, and then had them coated white by Airborn Coatings. I wrapped them, and then sprayed then with VHT white paint (didn't care for the brownish color of the wrap). I actually sprayed VHT silver first, then white - the VHT white alone seemed to dissappear as it soaked into the wrap. The silver seemed to give better coverage, and then I sprayed white over the silver.

Ran into the guy who built my headers a year later, and he said he did not recommend wrapping them. Said the extra heat caused by having them wrapped could cause failure due to hyrogen embrittlement. After some discussion with him, I came to the conclusion that it might be more of an issue for a race car with extremely high temp changes, than it might be on a street-driven car.

Have not taken the wrap off, and have had no problems.

regards,

Jeff

[flipper35]

If you call a major manufacturer you will find they will void any warranty if they are wrapped. It is hard to tell what shape your headers are in just by looking at them because it weakens the metal. I had mine wrapped for years, but since they are custom I took it off and had them ceramic coated. I think the wrap keeps the heat in better and I could bump them when the car was running with only a very minor burn.

[Michael C Henry]

I bought a used EM.It had wrapped headers.They looked great and engine bay temps were OK.A week later #7( left next to the rear) pipe blew out at the first bend from port.I unwrapped the rest and all were all cracked (many many small crackes and fractures.They were just painted.I was told heat embrittlement was common with wrapped pipes. They keep the heat in at the expense of the headers. I had new headers and sidepipes built and then had them ceramic coated. I'm hopping they will last for ever.

[jjtarnow]

I'm researching wrapping my headers. When I bought my E-M the headers were wrapped. A few months later I thought I had a simple exhaust gasket leak only to find major cracks and breaks all over my right bank header. My concern is that without wrap the heat could ignite the fiberglass (keep in mind I have a 514 (460 block) and the pipes are somewhat close to the sides (inch and a half at one point)). Any thoughts?


Josh

[Michael C Henry]

My EM has heat sheilds over the front and sides of both the footboxes.They are thin alluminum with a 1/2" of aluminumized fiberglass insulation between the aluminum and the fibrglass footbox.I had to remake all pannels because they had been all banged up and cracked .The new headers had a flange before the headers went through the body and I had to make a void in the heat sheild lower outside for clearence.The short pipe sections did make having the pipes coated inside doable.

[Rick Parker]

This has been discussed extensively previously, but the condensed version is that mild steel will crystalize if it is unable to rid itself of the heat generated by the exhaust. The wrapping does an excellent job of retaining (not radiating) the heat in the pipes and at that point the pipes become an expendable commodity. In my build (see my gallery) I had areas on the driver side that I was quite concerned about (1/2" ) and after ceramic coating and reflective matting everything appears to be ok. The aluminized reflective matting does a very good job and at the same time provides an "Air Gap" to some degree. If I were to do it again I would make the headers out of 321 Stainless without the coating as stainless by nature retains more of the heat and radiates less.

Rick

[Roscoe]

I've had my headers wrapped for over 4 years and 21k miles, no problem.

The problem with header deterioration is moisture. When you wrap headers you should spray them with high temp paint and bake them. This will seal the material and prevent moisture from getting into the wrap.

Roscoe

[Michael C Henry]

The fiberglass doesn't burn but it looks like it explodes when the pipe fails and all that throbbing -pulsing exhaust hitts it.I'm certain that the fiberglass of the footboxes wouldn't like it either.I still have the original exhaust in the attic above the garage as proof.I thought that the short lengths that my replacement exhaust were in lent it"s self to ceramic coating inside and out.and was the best choice.Heat is still there .Not as good as glass wrap but better than bare pipes .keeping air moving is enought to keep everything alive and comfortable.This is one of the concerns with my upcoming start up and cam breakin. Last time I let it run in place for extended time it burnt outline of engine and exhaust into lawn.I want one of those 4ft fans I saw at Home Depot.

[Bart Carter]

It would seem to me that if you first ceramic coated the headers inside and out to protect them from extra heat, hydrogen embrittlement and moisture, the wrapping would not be a problem.

[jjtarnow]

Does anyone have suggestions regarding who they used to coat their headers? What the turn around time was and cost?

Josh

[ERA Chas]

I have mild steel primaries on my SO which were wrapped for 3years with no damage. The heat retention was so good, that I had to re-jet the carbs as the vacuum signal improved. The deterioration of the wrap [got brown and freyed] prompted me to remove it and have them coated.
I chose Swain Tech's white ceramic which is .015" thick and applied throughly in and out of each pipe. It's a coarse coating, not meant to be pretty and shiney which gives excellent results.
Also didn't have to re-jet as the vacuum signal remained high. The stuff's nearly bulletproof.
Don't remember the price but they're nice people and I got good turnaround.
Hope this helps.