Header Wrapping

[Geking]

I did search and found http://forums.hybridz.org/index.php?/topic/74897-wrapping-headers/page__p__713175__fromsearch__1entry713175

 

Has varying reports. I am using cheap Ebay headers so I wont worry about them rusting through or cracking after 100,000 miles.

 

The reason why I am doing this is the wiring harness tape on the passenger side is burning off due to the temps. (gen2 chevy small block) I tried some advance auto parts wrap, and the stuff smoked like crazy, went darker and then caught fire when I held the motor at 3k. Am I using the wrap wrong, should make some sort of heat shield (if so I would like to hear your oppinion on how to make and mount it) or some other option.

 

Thanks in advance.

[SidWell]

I did search and found http://forums.hybridz.org/index.php?/topic/74897-wrapping-headers/page__p__713175__fromsearch__1entry713175

 

Has varying reports. I am using cheap Ebay headers so I wont worry about them rusting through or cracking after 100,000 miles.

 

The reason why I am doing this is the wiring harness tape on the passenger side is burning off due to the temps. (gen2 chevy small block) I tried some advance auto parts wrap, and the stuff smoked like crazy, went darker and then caught fire when I held the motor at 3k. Am I using the wrap wrong, should make some sort of heat shield (if so I would like to hear your oppinion on how to make and mount it) or some other option.

 

Thanks in advance.

 

It sounds like you got the wrong wrap from the parts store. There are two basic applications: one for headers and very high temps, the other is for water systems and keeping heat away from the fuel lines. I suspect you purchased the lower temp wrap. Make sure the stuff you purchase says it is made for headers.

Edited February 21, 2010 by SidWell

[strotter]

I cut a piece of 1 1/2 90° aluminum angle to cover the wiring, fabricated a couple of little brackets to hold it in place to form a cover for the wiring. Goes on and off easily, looks fairly neat, protects from heat, and gives access to the wiring loom when I add, subtract, or replace some wires. If i were doing it again, I'd get a piece of 2" tube, section it in half.

[Geking]

It sounds like you got the wrong wrap from the parts store. There are two basic applications: one for headers and very high temps, the other is for water systems and keeping heat away from the fuel lines. I suspect you purchased the lower temp wrap. Make sure the stuff you purchase says it is made for headers.

Believe it or not, it is labeled as header wrap Only a small part caught fire and it went out quickly once I turned the motor off, I might let them 'cook' for a bit next time I fire the motor and see what happens, with a fire extinguisher of course.

 

Strotter, I do like your idea, cleans up the bay a little and protects the wiring. Now I just need to see if I can fit all my wiring into a small L stock. (I have stock harness, 4 gauge wire from the alt to the batt, and a rather thick shielded 4 pair wire that I am using to get USB for the GPS unit under the driver's side fiberglass headlight bucket.) If the header wrap eventually cooperates I will use both, as the manifolds have paint runs and what not on them.

 

Thank you both.

[Daeron]

The aluminum wire cover could function more as a cooker for the wire harness unless used in tandem with some other barrier to keep the heat from the header away from the aluminum cover itself. The radiant heat that would otherwise go straight into your harness and cause an issue, will instead rapidly heat the aluminum wire cover and while some of it will be kept out, if you are THAT close, you'll just wind up cooking the whole affair together.

 

I mean, the cover would probably be more help than harm, but I am pointing out that it's like shooting your foot with a .22 rather than a .45, unless there's another heat shield. The wire cover WOULD let you get away with a rinky-dink heat shield, though, while tucking the harness away at the same time.

[strotter]

Daeron, your concerns crossed my mind when I installed the thing. I think there are a couple of things working for the aluminum cover: first, it effectively stops radiant heat from the headers, which is quite intense in that area - I have about 4" clearance at the closest point. I went to some effort to stand the cover off from the wiring - I'd estimate I have about an inch between the cover and the wiring, so there's plenty of room for air to move beneath it. Second, aluminum is a great conductor; my cover runs almost the entire length of the engine compartment. Fully warmed up on a hot day (around here, we get well over 110 some days July/August), the ends are quite warm - not "burn your fingers" warm, but getting up there. At the same time, the center (near the headers) isn't a great deal hotter. I think it's transferring heat out to the ends, where the air is cooler. I had the melting wires problem early on, now it's ok. Overall it works well.

 

If I were doing it again, though, I think I might route the wires out through the fender well, possibly through some 2" or so tubing. It'd make the engine compartment look cleaner, let me get rid of those ridiculous, torn-up wire holders, and free up more room to get to the starter.

[Daeron]

Daeron, your concerns crossed my mind when I installed the thing. I think there are a couple of things working for the aluminum cover:

 

Excellent! I just had to point it out; its part of my nature. One rule my family and I learned this weekend: no such thing as too many layers of heat shielding!! (long, mostly irrelevant story, heh)

[Tony D]

I was forced to install headers on the daily driver turd, and was really impressed by the header blanket sold by MSA.

I wrapped my old set of headers, but this time put the blanket on instead using their little clamps and safety wire. There was PLENTY left over, so I could wrap whatever else I wanted for 'double protection'---but the headers are not causing any issues that the stock manifold did on my SU's---much different than my experience with the header wrap I had on another car.

 

This blanket was pretty heavy, and seems to do a VERY good job keeping header heat where it's supposed to be: next to the headers and not in the engine bay. It's a PITA to get on, but it seems to work superbly!

Edited February 26, 2010 by Tony D

[Daeron]

Thanks Tony... We had a heat soak issue with my brother's ITS car last weekend, and probably have it solved with a sheetmetal heatshield (already had that) combined with two layers of aluminized sticky expensive insulation material my brother bought at the track. However, as you said, "keep the heat where it belongs, out of the engine bay......"

[ezzzzzzz]

There are so many good products out there to reduce heat damage. One item is http://www.fuelsafe.com/store/parts-accessories/heat-safe.html which is added to the surface of items you want to protect. Another supplier is http://www.heatshieldproducts.com/p_heat_shield_mat.php which has a large variety of products. I've used header wrap on a DD and was disappointed. Actually, it isn't designed or intended for such a use. In my case, the tri-y header retained so much heat that it was glowing bright red and hurting more than helping. I know that some will instantly say the air/fuel was off but not in this case (2.5 four cylinder w/ single Weber downdraft tuned with an exhaust sniffer). Headers create a lot more underhood heat than the cast manifolds. In most cases the latter is fully functional and quieter but doesn't have the visual allure of a header setup. I'm using stock C2 headers on the LS1 in my 71 Land Rover. The fit and quality are hard to beat at any price. Considering that a header adds minimal hp/tq gains in most street applications I prefer to use the factory manifold(s) when I can. Getting the heat out of the bay should be the focus by proper venting. I opt to use shielding on the components I want to protect rather than an exhaust wrap but that's just me. Obviously, the track is a different environment where wrapping has it's advantages and the cars have an opportunity to cool down after a spirited run in most cases. Take all of this with a grain of salt. What the hell do I know?

Edited February 26, 2010 by ezzzzzzz

[brokebolt]

...I tried some advance auto parts wrap, and the stuff smoked like crazy, went darker and then caught fire when I held the motor at 3k...

Wow!!! That would be interesting to see! Not that I doubt they caught fire just surprised they did!!! Very dangerous indeed!!!

 

I have always used Cool It Termo-Tec Natural 2 inch wide header wrap. They make a copper and black version as well. I'm sure their are many others that will work just as well. But to comment on your experience, mine too went dark after a minimal run time, smoked for a while until they went dark, but no fire to report...yet. I don't DD the car anymore but the sport 600 motorcycle I did the headers on was used extensively without any problems. The real kicker on the bike was that if you run the pipe under the oil drain plug and the o-ring gets too hot and oil leaks on them, they tend to smoke more and longer... I'm willing to guess that's oil down there burning away though... "Use a Copper gasket next time, Copper..."

 

Heat shields used in conjunction with header wrap should provide decent results. I've never used the thermo blankets or Heat-Safe products but I say give it a whirl and report back your experience.

 

I like to take a more scientific approach to things, install a couple of remote temp gauges, like that which you might find at any home improvement store for measuring 'outside the house' temps, install several under the hood in various locations, drive the car around noting weather conditions and gauge temps in various driving scenarios (a buddy in the passenger seat helps) and then install one heat isolation item at a time, trying to repeat the same conditions each time. That should give you some 'real world data' that actually makes sense. And way better then slogans on the packaging that proclaims "Reduces under-hood temps by (as much as) 70%!!! *results not typical*"

 

Just my $0.02

Edited February 26, 2010 by brokebolt