Header wrap

[dontoe]

Anyone using/tried the fabric header wrap? I bought three rolls from JC Whitney a while back and wondered if it is a waste to put on me 73 K-5 with Thorley headers.

 

[big83chevy4x4]

my friend put them on his ford and they cracked down just about every tube in about 6 months. im not gonna use them.

 

[dontoe]

Cracked down? What'cha mean?

 

[84_Chevy_K10]

Header wrap ruins headers. Get coated headers if you want to hold the heat in.

 

[sled_dog]

with thorley headers they should already be coated, so basically you'd be puting them on just to protect spark plug wires, and as long as you route them right there is no problem.

 

[big83chevy4x4]

the cracks ran along the tube, most were about 1' long.

 

[dontoe]

I bought the chrome Thorley headers a few years back. Hoping the wrap would substantially reduce the heat in the engine compartment and floorboard. Actual tubes cracked or the wrap?

 

[big83chevy4x4]

the tubes, he had to replace the headers

 

[dontoe]

WoW /forums/images/graemlins/doah.gif Wonder why? /forums/images/graemlins/confused.gif

 

[84_Chevy_K10]

[ QUOTE ]
WoW /forums/images/graemlins/doah.gif Wonder why? /forums/images/graemlins/confused.gif

[/ QUOTE ]

Because they get hotter this way, heat = expansion = cracks.

 

[sickquad]

I used to work with a guy that made custom headers for hot rods. I asked him about the wrap and he said never do it. Gave the same reason of expansion and cracks and such.

-Chris

 

[tx_sub]

the wrap works to reduce underhood temps and speed up exhaust flow but at the cost of accelerated header breakdown. cracks like you guys are describing would be caused by temperature differentials in the material. any sudden change in temp would cause the molecular structure to expand or contract. any existing stress concentrations would be increased and start crack propagation. at those temperatures the exhaust gasses may react more readily with the steel inside the tubes to accelerate breakdown. racers who do limited runs on their engine components can afford to use the wrap. they tear apart their engines almost as often as we fill up our gas tanks.

 

[dyeager535]

Yep, I agree, don't run it.

Headman states not to use it as it voids their warranty.

What I have experienced first hand though, is that headers coated INTERNALLY greatly reduce the amount of heat dissipated into the engine bay. I've seen the same in testing in magazine articles.