So I am re-wrapping the fiberglass around the header (Merge 4:1) and the oil lines that are suspended between two.
I got the wrap locally, but they had none of the stainless straps. The straps in question are thin, impervious to heat as seen for four years of use, and 'snippable' (can cut the leetle guys with a wire cutter.)
Local FLAPS people sell the wrap and never heard of the proper ties. So they suggested the stainless doobies used to tie off universal joint boots. noooooo, they don't tie down far enough and man are they impossible to cut or what? Had to use a dremel.
Dunno. I'm just a-whining. I love living in the sticks except when I need some kinda urban thing.
You should be able to use plastic cable ties on the heat insulator if it is of any value. Remember that header wrap can crack headers in very warm climate.
Not entirely sure about physics behind it, I know for sure Rallye Raid'ers in vintage cars, like in the Peking to Paris are strongly advised against it. It could relate to cast iron manifolds only? It is a debated subject, but those who had failures had heat wrap, the others not..
I think it really might relate to cast iron because it is brittle and especially because it is unyielding. When my header was installed, it yielded fairly easily to bending it to fit properly (and tightly). I have dual quiet packs on the header, and they are supported by strong springs to the chassis. Springs let it move a bit when necessary.
I've studied a fair amount of information regarding exhaust pipe heat. It is interesting that the temperature of the exhaust gas falls at a huge rate per inch. The first three or four inches are so hot that the header radiates strong infrared. Then the temp drops until at the exit of the muffler, it's just warm.
The infrared radiation can head all the components near that part of the header and no amount of air cooling or wind can help any more than you can blow the beam of a flashlight aside - because infrared is radiation.
Wrapping helps a lot in that regard.
With wraps, the temperature remains high so that the gasses flow faster
- there is less cooling due to denser (cooler) air in the pipe.
The Bad News is the heat is very high were the wrapping stops - if you were to have the header blow at your pants leg, you could be badly burned.
The ultimate bad news is that my full-flow oil lines passed too close to the end of the wrapping. A line melted, spewing Mobil-1 straight onto the unwrapped part and EXPLODED in a ball of flame that the cars behind me will probably never forget. (I saw it immediately and hit the kill switch. Kill switches - some thing I learned from building motorcycles. A very good idea.)
But the explosion and its aftermath is a story for another day.
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