Exhaust Header Blankets? Good or Not?

Mechanogeek

Mechanogeek

True Classic
Does anyone here have any long-term experience with a header blanket? I know there is a lot of discussion concerning heat in the engine bay, and I only found a couple posts about exhaust wraps...

Just curious if anyone has used them, and if so, whether they saw the engine bay temperatures drop considerably, and whether they encountered any long term issues?
 
Mechanogeek said:
Does anyone here have any long-term experience with a header blanket? I know there is a lot of discussion concerning heat in the engine bay, and I only found a couple posts about exhaust wraps...

Just curious if anyone has used them, and if so, whether they saw the engine bay temperatures drop considerably, and whether they encountered any long term issues?
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Using exhaust wrap will void most header manufacturers warranty, that should tell you something. Wraps hold in the condensation that occurs on cool-down, and accelerated rusting is the inevitable and speedy result. Ceramic coat if at all possible. Be sure to shop around for a good coater, and don't automatically go with the low bidder - there are some coatings out there that are pretty close to useless. Jet Hot used to be the go-to name, but I'm not sure they're still king of that hill.

Pete
 
I recommend the ceramic thermal barrier coatings over a wrap. As noted above the wrap will destroy the header. The thermal barrier will extend its life and reduce engine bay temps.
 
Personally I like to do both.
Ceramic coating will protect the underlying metal and offers some thermal insulation. A good wrap material offers better thermal insulation but will support rusting, as noted. The combination of both, ceramic coat then wrap, prevents the rust issue and offers incredible temp reduction in the engine bay. But that's just my preference. I also prefer to coat the inside of the manifold/header (unless it is stainless steel) as well; mainly to protect that side from rusting, but it also offers a bit more insulation. Additionally it seems to reduce carbon build up inside.
I'm sure this sounds like a bit of overkill, but it has worked very well for me. However it should also be noted, on extremely hot exhausts (e.g. turbo systems) retaining too much heat in the manifold will lead to cracking issues. So each application requires a unique approach.

I agree with Pete, not all coatings are created equal and not all services do the same level of prep and application (like any type of surface coating, it makes a difference how it is done). Although I will note I had a very bad experience with "Jet Hot". It was a customer service issue, so I'm not knocking their product, but it was severe enough that I will never do business with them again. I'll just say it cost me a irreplaceable vintage component and they would not do anything to compensate, despite guaranteeing the outcome in advance.
 
Shown is a header that was wrapped. I don't recall the length of time it took for this to occur but it was pretty quick maybe a season?? As mentioned above "It flaked apart like a piece of mica" describes the behavior perfectly.
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No actual analysis on my part but I would assume heat. No evidence of rust and the car was not stored outside or driven in the rain.
 
You said it occured in a "season", so I assume this was a race engine? If so, that might qualify for what I mentioned earlier as "extremely hot exhausts". In which case retaining too much heat isn't good (as I said earlier). Depending on the metal content, if it gets too hot it will change its molecular structure and begin to show degradation. For example this would not happen to stainless steel or even higher quality mild steels (I'm not suggesting yours wasn't high quality). Two things to keep in mind; 1) by ceramic coating the metal first (particularly both inside and outside), the metal is better protected and the heat will carry along the exhaust path better, and 2) on a street driven engine the level of exhaust temps won't get anywhere near that of a race engine. But I'm just speculating. Every application will have its own requirements.
 
Dr.Jeff said:
You said it occured in a "season", so I assume this was a race engine? If so, that might qualify for what I mentioned earlier as "extremely hot exhausts". In which case retaining too much heat isn't good (as I said earlier). Depending on the metal content, if it gets too hot it will change its molecular structure and begin to show degradation. For example this would not happen to stainless steel or even higher quality mild steels (I'm not suggesting yours wasn't high quality). Two things to keep in mind; 1) by ceramic coating the metal first (particularly both inside and outside), the metal is better protected and the heat will carry along the exhaust path better, and 2) on a street driven engine the level of exhaust temps won't get anywhere near that of a race engine. But I'm just speculating. Every application will have its own requirements.
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Dr, Jeff, same header w/o the wrap didn't suffer the same degradation in the same application. And as Brad related, it occurred in a relatively short period of time. Only thing that changed is the wrap. The wrap was very effective in keeping underhood temps down though. Just kinda expensive on that header - IAP long tube versions. Perhaps headers made of other materials would fare better? Don't know.
 
So then, good at keeping underhood temperatures down. Very harsh on headers. What about the Fiat stock cast iron exhaust manifold? Same issues?

I ask because I am examining heat control possibilities for my stock engine application.

BTW - Thanks for all the feedback so far. It has helped.
 
Dr.Jeff said:
You said it occured in a "season", so I assume this was a race engine? If so, that might qualify for what I mentioned earlier as "extremely hot exhausts". In which case retaining too much heat isn't good (as I said earlier). Depending on the metal content, if it gets too hot it will change its molecular structure and begin to show degradation. For example this would not happen to stainless steel or even higher quality mild steels (I'm not suggesting yours wasn't high quality). Two things to keep in mind; 1) by ceramic coating the metal first (particularly both inside and outside), the metal is better protected and the heat will carry along the exhaust path better, and 2) on a street driven engine the level of exhaust temps won't get anywhere near that of a race engine. But I'm just speculating. Every application will have its own requirements.
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No, my street driven car here in Michigan season meant summer. The header was an IAP header. I would assume the steel was 1008/1010 carbon steel.
 
My Abarth powered X1/9 I have the Cat wrapped, the turbo has a blanket as well and then some heat shielding. All of this reduces the engine bay temps. Just to let you know the stock Abarth exhaust manifold is made from 304 Stainless Steel.

TonyK.

Grimsby Ontario Canada.
 
It also depends on the climate in your location. Low elevation, sea coast: bad. High elevation, desert: Good. I use header wrap on my American iron with very good results and no noticeable rust. But it is single digit humidity here most of the year. I am looking forward to the next time I have the exhaust manifolds off the X. I have the wrap sitting on the shelf waiting.
 
Just wrwaped my pipes. Pretty low humidity, car stored inside and not driven in the rain. No salt on our roads. We'll see.
 
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