I have to run my exhaust through a couple of tight areas, I was wondering which would be the best at protecting the starter, master cyl, brake and fuel lines. Making heat shields or using header wrap?
I always make heat shields. ('deflectors' in some cases; but usually 7075 aluminum sheet) Header wrap always looks like a band-aid to me... In the old days, "header Rap" meant the noise they'd make! I know, I know... BTW, did you know you are on post # 666??? OOOOhhhh... I noticed that...
I've used both on my Cadillac...I built a heat shield between the under floor brake master cylinder and the exhaust. I sprayed the heat shield with Lizardskin, both sides...but, since I'm still feeling heat on the floorboard directly above the exhaust pipe (and alongside the heat shield protecting the master cylinder) I wrapped the pipe with header wrap...there's some black stuff you can get now that you don't have to soak in water first... I bought a fifteen foot roll, $17.00, and wrapped a 2 1/4" pipe, from the headers back a total of seven feet. It made quite a difference in the floor heat, so I imagine it helped the master cylinder as well. Better safe than sorry,,,!!! R-
Header wrap might be better for protecting the parts, but shields might be better for protecting headers. At least that's what the header companies say, they usually won't warranty headers that have been wrapped. I don't use either....things get hot, but I make sure to leave plenty of room for stuff like fuel and brake lines. Put the exhaust in first, then route the smaller lines somewhere else.
My understanding is that over the long haul wrap will cook the carbon out of the steel & it can fail.
i did not know headers where heat treated.. shrugs. not sure how they would fail. interesting. chris.
i guess you can get to the point were the flange gets warped and your seal is ruined....but thats just in theory... other than that i would guess going with heat wrap...even though a shield might be easier to make...and wont leave you itchy in the end.
How does an old car body react, when put through intense heat...not very well. No heat treating prior there. Its pretty much the same with headers, youre taking basically thin wall tubing, and concentrating the heat within them. Notice how quick a regular pair of headers cools off, compared to a cast iron exhaust manifold. Instead of shedding the heat, its being thermally kept in. That combined with water, doesn't help either. Then again, it depends on what you expect out of your headers. Some cheapie $100.00 ones, that you don't care about...go for it, if ya want. But they wont live as long.
there has been a myriad of problems with rust forming under the wrap. Condensation from pipes cooling, humid areas - traps moisture and the dreaded deterioration begins. dj
I used a wrap on a custome snake pit header I made for a ford 300 inline. It literally caught on fire! I figured it must of been from all the tight bends of the tubing, who knows. Ive put wrap on 350 headers, 440 headers, inline headers and even harley header pipes. It looks ok on some things, but Im still not sold. Headers still get really hot, regardless of a wrap.
I can speak from experience. The carbon steel pipe was wrapped with a sandwich material which consisted of aluminum outer & asbestos inner. I took the covering off & the metal was coated with heat scale. The appearance reminded me of someone who stayed out on the beach too long!! The heat being contained inside the insulated covering cause the pipe to become deformed. This happened over 30K miles of use. I replaced the carbon steel pipe with one made from stainless steel.
deal is....wraps look like a Band-Aid® - we don't do that here. All mods are permanent...until replaced with the next permanent thing. Make shields....show off your metal-working skills rather than your EMS talents dj
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