This is common. The Spitfire's lack of firewall insulation and the joints of
the tranny
cover cause a lot of heat to get into the passenger compartment. (And exhaust
fumes, too, if your exhaust system has leaks.) The fact that you are sitting
only a couple of inches from the engine doesn't help, either.
If your original cardboard tranny cover is not busted, you don't necessarily
have to replace
it. But most of them are in pretty bad shape after all these years. To inspect
or remove the tranny cover you need to first remove the padding piece that runs
across the bottom center of the dashboard, then the radio and the center
console thing,
and finally the shifter knob (just unscrew it) and the carpet. Inspect the
cover for cracks
and warping. See if it is properly screwed in place and if hot air leaks
through the joints.
Drive around with a passenger and have you and them feel for drafts.
If the rubber boot around the shift lever is intact, air should not leak out
from there.
To fully remove the cover, undo the screws around its base, the metal ring
around
the shifter boot, and also the two screws that hold the upper front corners
(accessible
from the engine compartment).
The tranny cover originally had insulation attached to the underside.
This needs to be in place to keep the heat and noise down. If this is missing
or damaged, or if you add a plastic cover, you really need to design and
install
some suitable insulation.
The ideal insulation, IMHO, would be a one to two-inch thick layer
of dense styrofoam molded directly onto the entire inner surface
of the tranny cover. A pity they don't come that way!
You might be able to cut strips or tiles from a sheet of rigid styrofoam
insulation and glue them to the underside of the cover. Sort
of like the planking of a wooden boat, or the space shuttle
tiles, but inside out :-)
Obviously the rubber seal between the cover and the body shell is important.
You may have to augment it with some sort of caulking, especially
for the joints between the front of the cover and the firewall. Make sure
you don't caulk it in place too well, or you may never get it out again.
You might try caulking with the latex-based foam-in-a-can. It is many times
less messy than the urethane variety, and the cured foam is rather weak,
so it would not be too hard to break the seam apart later.
Also look at ALL the holes in the firewall where the wire harness, etc., pass
through.
You may need to replace some of the rubber seals or find some other
substance to seal the holes. Also make sure the rubber boots in front of the
brake and clutch master cylinders are intact. All it takes is one 1/2"
unsealed hole
to make a blast of hot air!
I have applied pieces of "Dynamat" (those self-adhesive sheets of tar-like
stuff) to the inside lower
portion of the firewall, as far up as the flat "shelf". This keeps things a
bit cooler
and quieter, but it all the pieces of Dynamat had to be carefully cut to shape
to
fit around all the protrusions, seams, etc. in the firewall.
Also also consider adding more insulation (a.k.a. "underfelt") under the front
carpet pieces.
Good luck,
Doug Braun
'72 Spit
At 01:20 PM 2/24/2004 +0000, you wrote:
>I could use your thoughts on the possible/likely causes of heat in the
>interior of my '76 Spitfire. I've turned off the heater at the valve, and
>manually closed the vents, so I'm pretty sure the heat is leaking (more like
>pouring) in from the engine and drivetrain. I can feel it at our feet and
>just generally blasting in from under the dash/through the firewall (even
>shooting up out of the gearshift boot). A friend tells me I should install an
>ABS tranny cover, but I wanted to see if there might be any other less
>difficult and expensive things to try first.
>
>If not, and the tranny cover replacement is the thing to do, I definitely need
>some help. I've found the cover itself, but I can't find anyplace that sells
>the cover for the cover (carpet, vinyl, whatever). It's always part of a
>complete carpet kit (which I don't need). Can you get that separately (in
>tan)? Also, what seals, installation parts, etc. do you need in addition to
>the cover? In addition to the new cover, should I try to stuff insulation in
>and/or around it?
>
>Finally, what's the process for removing and replacing the cover - do you have
>to remove the shift lever? Any hints, secrets, special incantations? Thanks
>in advance for any help or guidance.
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