The 24 Hours of Lemons Forums → Lemons Tech → sealing up firewall questions
we had to do a lot of reconstruction on the firewall, basically the trunk disappeared so i built a box around the fuel cell out of sheetmetal.
there's a few gaps around the edges, so we need a quick way to seal the edges. Can I use expanding foam or RTV silicone to do this? Structurally the metal isn't going anywhere, we riveted the crap out of it.
I have a question on this as well. We pulled our ac, but still have the 2 holes where it passes into the firewall. The exchanger is still in the car, so there is no place where engine bay air meets cabin air (aka its still sealed, just a continuous loop back to the firewall. Is this OK?
I got a response from jay in an email:
Expanding foam (or the equivalent patch) isn't good enough. If you've got cracks in the seams, you need to attach angle pieces (you can buy pre-formed 90-degree aluminum strips at most hardware stores in the HVAC section) that are big enough to cover the cracks completely. If you're the a/c holes guy, patch the holes over with metal cutouts held by self-tapping screws.
well.. this might be rather difficult. 
rushman,
The exchanger should be OK. From what you've said it sounds just as sealed as anything else going through the firewall (wires, hoses, steering wheel, etc). I suggest you send a picture to Jay. Barring that, the easiest course of action is just to sawzall anything sticking out and then cover it with a piece of sheetmetal.
Two words for you...aluminum tape.
Two words for you...aluminum tape.
did they pass that? and where can i get some?
so tomorrow i'll be getting the lid for this done, plus i have a corner on the front with some large gaps that i need to deal with.. the seams pictured aren't that bad, honestly i think a bead of RTV would make it water-tight.. i'm just really nervous about tech.
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