Umm...Gearbox Insulation pad

[andrewh]

I have just been trying to fit the insulating pad on top of the gearbox ( 4.2 synchro) and under the cover. Not a chance. Its about 2 inches fit, very dense and just too much material to fit under there. Anyone managed it or got a better recommendation. I recall buying a pad from SNG for the 3.8 which was very much more realistic in terms of size than the one they just supplied for the 4.2?

[Heuer]

A piece of foam from somewhere like Dunelm is what I have used. Easy to cut and you can choose the thickness and compression to match your needs.

[andrewh]

Thanks David. Will try to find a Dunelm near by.

[Tbob]

I skipped the foam pad and covered the underside with Dynamat. Cool and quiet, and it fits without headaches.

[andrewh]

ok, another option I guess. I have now bought some foam from Dunelm and will use that. I did use Dynamat on my previous restoration but on the outside of the tunnel. Its good stuff!

[Heuer]

Dynamat is excellent at stopping reflective heat (hence the silver) but not so good with conductive heat. So the rule is to use Dynamat to bounce heat away and install it on the underside of the transmission tunnel or firewall. Installing it on the inside of the car is counter productive as you are reflecting heat from the inside of the car back into ......... err the inside. To insulate the inside of the tub you need to use something like Koolmat which insulates against heat conduction. So think heat reflection and heat conduction. Dynamat on the underside with Koolmat on the inside.

As for Andrew's question the upholstery foam is the best way forward.

[andrewh]

thats new news to me!! I don't doubt you but I had Mick Turley install it throughout my 3.8 and I have to say that the car does not get hot and it of course has the added benefit of making the car feel quieter and generally more well built. I will check its performance tomorrow on route to Bicester

[andrewh]

this is the link to the Dynomat website detailing its fitment to the inside of vehicles, as per my installation
http://www.dynamat.com/automotive-and-t ... at-xtreme/
viewtopic.php?f=8&t=2185&start=80

[Heuer]

Dynamat without the silver backing (or fronting) would indeed work as an insulator but the silver reflective layer is, like a mirror, designed to 'bounce' radiant heat away. So it is redundant on the inside of the car and would be better used between the gearbox and the body or between the diff and the body. You insulate to stop conducted heat through metal (e.g. oven gloves) you add shiny material to keep the innards cool (e.g. cooking foil) from radiant heat. Simple first year science - insulate with felt, reflect heat away with foil. Now obviously marketing may say something different but physics says otherwise. Every trimmer I have spoken to hates Dynamat with a vengeance as nothing sticks to it properly. Besides, no mainstream car producer uses Dynamat or similar for interiors it as far as I know.

[64etype]

I fabricated a sandwiched pad. The bottom layer is cut from a sheet of the silver Mylar bubble insulation available from home improvement stores. The second layer is adhesive backed Dynaliner (not Dynamat). The sound pad/heat deflector is sized slightly larger then the hole in the tunnel. An opening is cut out for the shift tower. The sandwich is fairly flexible, but stiff enough not to droop (although I added some "S" hooks around the perimeter of the opening just in case). It's a sort of dome that hovers over the top of the transmission case and curves outward and downward against the sides of the tunnel. The mylar layer is both a heat deflector and an insulator (air bubbles). The DynaLiner is a (closed cell) noise dampener plus heat barrier. While the Dynamat company likes to mention the heat rejection characteristics of the aluminum backing of Dynamat, it's primary design function is noise control.

Since my car is located in the American Southwest and it was a ground up restoration with complete access, I placed extra emphasis on heat reduction in the cabin...full coverage aluminum honeycomb heat shield between the frame rails (above mufflers), DEI heat padding in the transmission tunnel, ceramic coating on bottom side of transmission cover, and Jet Hot type ceramic coating on the entire exhaust system including mufflers (heat barrier and rust preventative). The interior side has a layer of Dynamat for sound suppression, and then a layer of Dynaliner (sound and heat). No jute padding in this car. No Kool Mat. As already stated...heat rejection outside, noise control inside.

[Heuer]

Actually I do have Dynamat lining the interior of my FHC and it does provide good sound and heat insulation but I think that is due to the bitumen like backing rather than the foil. I have Koolmat in my OTS which also acts as a good sound damper and is an excellent heat insulator. Both my wife and I agree the Koolmat is the more effective of the two.

[iani]

I managed to fit the overly large foam mat from SNGB on my car, it wasn't easy however and I was tempted to cut half of it away before I finally managed to get the cover on.

Ian

[64etype]

Here are some photos of heat solutions (I just figured out how to post from photo bucket).

Reflective bottom insulation (aluminum honeycomb center shield and DEI pad)



Killer dog guarding ceramic coated exhaust system



Transmission pad (mylar bubble plus dynaliner)