I want to reduce the temperature of my bonnet above the exhaust manifold.
In true locost fashion, I am thinking of bolting on an thin ali sheet about 15 mm from the bonnet and then filling up the space in between with an
insulator.
The wall cavity foam type stuff would be ideal but it is flammable so thinking of making a matrix of silicone sealant beads to keep air in
"cells" since I have that stuff.
Temperature I reckon should not be more than 120 C - is that ok for silicone sealnt stuff?
i hope its not flammable as i've packed my silencer with it, i'm also thinking about bonnet and side wall heat as its a prob in my kit
now when you say insulation do you mean that stuff in a can ? it goes everywhere but where you need it.
Wouldn't the air cells just get hot too? It might be best to get some small metal standoffs and allow the air to flow.
I've seen some sealants safe up to 250C but I guess it depends on what stuff you have?
quote:
Originally posted by graememk
i hope its not flammable as i've packed my silencer with it,
now when you say insulation do you mean that stuff in a can ? it goes everywhere but where you need it.
The last Silicone exhaust paste I saw was rated up to 300c
quote:
Originally posted by joneh
Wouldn't the air cells just get hot too? It might be best to get some small metal standoffs and allow the air to flow.
I've seen some sealants safe up to 250C but I guess it depends on what stuff you have?
How about using some alluminium cloth ? - it's designed for the job. I know it's a bit more expensive but it will be quicker to install and will perform much better.
quote:
Originally posted by RazMan
How about using some alluminium cloth ? - it's designed for the job. I know it's a bit more expensive but it will be quicker to install and will perform much better.
Bathroom silicone sealer and ally sheet will work just fine, though they may try to part company after a while.
Give them a try though, nothing to lose and the silicone will be fine at that sort of temp.
what about the fire blanket out of the kitchen ?
why not just get some ali sheet, create some thin ali strips and make them into spacers, rivet the lot together so you've got .........
*********thin ali sheet*************
*spacer*__________________*spacer*
*********thin ali sheet*************
no silicone worries now (short or long term) and the same effect.
edited to try and improve the ascii diagram
[Edited on 8/6/06 by MikeR]
Mike - that is what I am thinking but without the spacers since metal one would conduct heat.
current thinking is that a sheet about 10 mm away may work.
when driving, there will be air flow so under bonnet temp should be ok.
when stationary and idling, the stationary air "trapped" between the plate and bonnet will act as an insulator.
(I've already have the holes in the bonnet, just need to find the metal sheet)
For the time being, I'm keeping away from echasut wrap due to it trapping moisture and rustingthe manifold and it will be awkward to wrap round
the 2 traingular boxes (4-2-1).
[Edited on 9/6/06 by 02GF74]
i'd have thought (ie i'm no expert) that the amount of heat transmitted by a few small (1 inch) spacers would have been minimal
Rivnuts as spacers?