Heat wrap and erosion

[BOOT]

HEAT WRAP IS THE DEVIL!

Ok now that we got that out of the way, I plan to use some cast iron manifolds and I've wrapped a few sets of headers w/o problems but I've always wrapped them correctly. Anyways since I recently ported a set of cast iron manifolds it occurred to me that I may want to OVER wrap the parts I can't get to n let it maybe port itself.

Thoughts?


edit: Checked once in awhile n removed eventually.

[user-23911]

It's always been the devil.

Unfortunately, there's people who sell it and to do so they'll tell us otherwise.


There's nothing good about it.
Proper heat shielding is made from sheet metal.
It blocks radiated heat while allowing hot air to escape.

[Newold1]

On some of the hotboat offshore racing engines we put together we were using a HeaderShield metal system and they held up well with minimal corrosion and rust unlike that funky wrapping fabric type tape.

Talk to these people

http://www.headershield.com

[gnicholson]

aircraft engines etc use a heat blanket material sandwiched between thin stainless steel. that would work great im that application

[j-c-c]

HEAT WRAP IS THE DEVIL!

I've wrapped a few sets of headers w/o problems but I've always wrapped them correctly.

Please explain.

[BOOT]

I'm not trying to find another way to heat shield objects from burning/cooking, letting hot air escape defeats the point of heat shielding if your trying to reduce underhood temps.

Correctly means follow the directions and don't overwrap to speed up the erosion, not corrosion that so many think is the result. The trapped heat erodes the metal from the inside until it becomes so weak it crumbles. I want to try n control the effect for limited concentrated erosion then take the wrap off. THEN I'll have the manifold ceramic coated inside & out.

[user-23911]

I'm not trying to find another way to heat shield objects from burning/cooking, letting hot air escape defeats the point of heat shielding if your trying to reduce underhood temps.

But what is it that you're trying to achieve?

To me it's wires that you don't want melting, paint you don't want to blister and hoses you don't want to melt. Then there's sensors which fail prematurely with too much heat.


Underhood temps?........that's totally irrelevant. The air intake should always be in a place that sucks cold, not hot air.


All of the above are fixed by blocking radiated heat and allowing hot air to escape.
By allowing the hot air to escape, you're not increasing the temps of the exhaust pipes which WILL fail sooner if heat wrapped.

[digger]

One of the things higher Under hood temps does is degrade the life of rubber, plastics etc etc even if it's not subject to direct exhaust radiation

[BOOT]

I'm not trying to find another way to heat shield objects from burning/cooking, letting hot air escape defeats the point of heat shielding if your trying to reduce underhood temps.

Correctly means follow the directions and don't overwrap to speed up the erosion, not corrosion that so many think is the result. The trapped heat erodes the metal from the inside until it becomes so weak it crumbles. I want to try n control the effect for limited concentrated erosion then take the wrap off. THEN I'll have the manifold ceramic coated inside & out.

[Belgian1979]

Although overly expensive and complex, I could see how a double wall tube prevent to much heat in the engine bay.

[user-23911]

Double walled tubes were used some 30 years ago with early factory turbos on bikes, might have been Suzuki?

Needless to say , they had the same problems only worse.
The tube burned out from the inside.

[Belgian1979]

Double walled tubes were used some 30 years ago with early factory turbos on bikes, might have been Suzuki?

Needless to say , they had the same problems only worse.
The tube burned out from the inside.

Burned out or corroded. I assume corrosion as burning of gas produces water vapour that can condense in the tube when the motor is not running. A stainless would take care of that.

[user-23911]

It WAS stainless.


It's a really dumb idea.
No different from using heat wrap instead of sheet metal.
Pretty much all heat shielding from OEMs is sheet metal.
Because it lasts a long time and doesn't affect the life of the pipe.



Still waiting for an explaination as to why hot air in an engine compartment is a bad idea when you've got all the hot air from the radiator ?

[Belgian1979]

It WAS stainless.


It's a really dumb idea.
No different from using heat wrap instead of sheet metal.
Pretty much all heat shielding from OEMs is sheet metal.
Because it lasts a long time and doesn't affect the life of the pipe.



Still waiting for an explaination as to why hot air in an engine compartment is a bad idea when you've got all the hot air from the radiator ?

Simple because the exhaust tubes add that much more heat.

I still don't see how a stainless steel would rust and with an 321 ss it would be heat tolerant as well.

[j-c-c]

Well now I have a explanation of "heat wrap correctly", and i strongly disagree. Not so sure I have seen exhaust failure due to "erosion" from wrapping, although I don't doubt its possible. Citing moisture as a contributing failure factor with heat wrap IMO is mainly an old wives tail. Heat wrap mainly traps heat in the the wrapped tubing, and that causes two things to occur, gets the steel/carbon component to high enough temp it oxidizes (rusts) quickly, and it heat fatigues the metal as it takes it to such a high elevated temp it effectively heat treats the metal, and that causes problems as it cools faster upon shutdown then the metal prefers, to maintain any useful ductility, and it occurs every run/heat cycle, that the process is repeated, and the tubing eventually "crumbles" from gross heat fatigue. There is no way to "correctly wrap" tubing to prevent this eventual outcome, other on a non running motor, IMO