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Should I wrap my headers?


RisingSun280

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whattup everyone, i have an 83 280ZX Turbo. Been reading a lot about header wraps and header ceramic sprays. I've read that wraps can reduce under hood temperatures by up to 70%, however a lot of people say there are many downsides to wrapping. Is it even worth it?

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Well before this even progresses you dont have headers you have a cast iron exhaust manifold. Cast Iron exhaust manifolds should not be wrapped, it leads to cracking. 

As far as headers if they are properly sealed then wrapping is good and very effective. If not then the constant moisture/heat/cold cycles will destroy them over time. 

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No worries man, welcome. Try searching prior to posting in the future, these threads usually turn into a shit show. 

 

Start a build thread, let people see what your working with. 

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depends on the manufacturer. some manufactures stand behind their steel and welds, some don't. the reason some manufacturers won't warranty their headers after wrapping is because their welds will not stand up to the extra heat that is trapped by the thermal wrap...another reason is if people improperly wrap them, or they do not use a waterproof protectant over the wrap to ensure it is water tight.

 

So...not a good idea? Debatable. Cooler engine temperatures, more horsepower, ect...drawback is if you buy a cheapo header, it may pop welds, but lets be honest, that sucker will break anyway, and I have yet to see thermal wrap destroy a header that was of even decent quality. Maybe someone else can offer more input than what I have seen or I am aware of, but what I do know is, small engine...camper-loaded truck...header...yeah, been there, seen that, and the customer always comes back because it overheats on hills. How do you think the factory manifold cracked?

 

The motorhomes w/ headers I have worked on with properly applied thermal wrap seem to last longer and don't tend to pop welds, warp, or blow manifold gaskets. I know companies put the disclaimers on their labels about thermal wrap increasing weld temperature, but the truth is, a motorhome engine is usually overworked from the start, and without thermal wrap, the headers heat the engine bay up to the point where the cooling system cant keep up, and the motor home starts overheating and pinging, then EGT's go through the roof. Maybe my real world experience is co-incidental, but I have yet to replace exhaust components on a properly sealed thermal wrapped header setup, where as we often see motor homes and pickups used for towing in for cracked/warped headers, blown gaskets, or the "mysterious overheating issue that started the summer after installing my new pace setters"...but again, I may be wrong.

It wasn't an easy search, but the intel is there. It's nice to have a thread title so specific, so let's populate this bitch.

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I have been wrapping my headers as long as I have been using them. Under hood temps drop drastically in all cases. Every time I made sure the headers were were ceramic coated and wrapped properly, i.e. even overlapping, even distribution etc... and not once has a set failed on me. My current Z has had them 2 years, my d21 had them 2 years under heavy abuse, my z32 had them when I bought the car for 2 years already and they went another 2 years until the car was stolen. While I was a mechanic I wrapped many many headers, never a single complaint. 

 

Thats not to say the caution isnt warranted. Anyone who has had wrapped heads can attest that moisture to build up on the wrap and is steamed off when the engine warms up. A set of unprotected headers will most definitely take damage over time and a unprotected set using garbage steel and welds will fall apart in no time. This though is far from a valid reasons to not wrap headers and reap the gains of lower under hood temps and better exhaust flow through the primaries due to the insulation. If we discounted every mods and tech because of the side that does things incorrectly we would all be walking...

Cast manifolds are a different animal. Wrapping them no matter what technique is used causes hot spots. Thick cast manifolds are brittle and can't adapt to those hot spots and crack pretty easily. Cast manifolds dont have the surface area and thin walls of headers so they put off less heat overall and are almost naturally insulated as they are so the wrap is moot anyway. Just ceramic coat them and call it a day.

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I'm no expert, but I've done about 50k miles with my Hardbody's exhaust manifold wrapped - no problems so far. I also wrapped the coated header tubes on my Landcruiser truck - dramatically reduced the temp in the engine bay. Also no problems so far..

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Don't post pictures of your engine if it has a fram filter on it. Find out why first

 

Don't remove head or cam without finding out why you have to block the chain tensioner first and why.

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Any alteration voids a warranty, how can a company warranty a product after its been changed? 

Definitely something to keep in mind though if a person plants to return headers after 50k miles... 

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I wrapped a set of header years ago (not coated) not to lower under hood temps really, but to keep more heat in the pipes to help spool a turbo (different topic all together). I just knew they were going to rot off because of it, well, more specifically, because I had been told by everyone, but I was in a 'fuck it' mood and talked myself into it because they were ugly anyway and that would give me an excuse to buy new ones. That was 12 years ago and no matter how much I glare at them and say "rot you fuckers"...nothing.

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i wrap the pipe on my motard ... but its more about looks and less about the heat although it helps...... i like the look of wrap done correctly and tightly but it will trap moisture and rot steel tubes out....bikes exhaust is stainless...

 

i deal in a lot of ceramic coatings too but i dont use them anymore on my stuff .. there not as advertised ....... they seem to not stay ... i been blasting headers and manifolds ad high heat painting them and cycling them through he oven and having the best results so far .. .maybe its just cause a spray can cost 9 bux and ceramic is spendy ... i dunno im tired if seeing my ceramic shit go to crap ... or just trying to simplify things ..... the thinner the coating the less temp retention ....

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And I get the impression smoke doesn't exactly drive old ladylike. 12 years wrapped! Time for science experiment. Swap a new one in and let's see what's left of it. You got a few hundred bucks sitting around for science? Jk

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I don't have a few hundred bucks sitting around for food these days. Ha, for all I know, it might just be the thermal wrap with no metal under it. I have been really curious though, but they don't leak, so I have been afraid to 'fix' it.

 

Hell, for something that might be even worse, my sandrail header is wrapped. It has been charged through the salt water on many occasion. That's working on 7 years. 

 

PBRT1_zps98f9abe6.jpg

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Science says that chemical reactions slow with the cold and speed up with heat. The iron in steel is going to react to the corrosive exhaust gasses more if it's red or orange hot compared to cooler.

 

The buggy wrap is going to run cooler being out in the open like that with lots of air flow around it, Also the pipes aren't all jammed together.

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This is true, but I can tell you one thing for sure, they do glow under that, all the way up to the hot side of the turbo. One of the issues we run into with buggies and turbos is that the pipes get REALLY hot, but as soon as you kill it, the cold blowing air from the beach will cool them off really fast, thus making the metal brittle an almost like glass. Mix that with sailing through the air and landing hard with the weigh of the turbo on it and they many times will break. The way we got around this (kinda) was using really thick tubing to hold in heat longer after shut down. With me, that did last a little while longer, but I eventually got a crack. So far, with the thick tube, mixed with the wrap, it has not broken and I contribute that to a slower cool down time.

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I feel I should probably mention that I am not recommending wrapping headers, just relaying my own experience with the stuff. Header wrap is really not to keep under hood temps low (even though it does a little). What it is really for is to keep heat inside and improve scavenging. On an NA car, I have never seen a back to back comparison, but I do have doubts it would be very much of an increase, there are guys though, that if there is even a chance of an increase in something, they go for it and a bunch of little stuff will add up. Now, with a turbo car, there IS a huge difference, the more heat you can keep in the pipe, the quicker you will spool up. 

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  • 4 weeks later...

I wrapped the Hooker Competition Plus headers in my 425/427 BBC in my 1969 C20 Longhorn Pickup.

 

I wrapped the heads from flange to flange with a flexible, thick wrap (can't remember the brand but the stuff was almost like an Ace bandage going around bends.)

THEN, I coated them with a "Steatite" ceramic paste which hardens.

THEN, I wrapped them with heavy aluminum foil sticky duct tape.

 

Two things happened:

  1. I literally burned out the header tubes at the bend at the exhaust manifold flange.  The heater tubes turned to "welding slag."  RULE NUMBER ONE:  DO NOT wrap headers all the way to the flange - especially if there is a bend right at the flange.  Stay back at least 2 diameters (3 is even better.)
  2. The rest of the headers were like brand new and they had been on the truck for almost 10 years.  Usually the down tubes rot out where they make the bend to horizontal due to salt and water spray.  LESSON LEARNED:  You can really preserve headers if you went through the 3 layer process I used.  However, if you leave the wrap exposed, it is a water, oil, and dirt sponge and I would guess it accelerates header rot.
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