by dinofritz » Fri Feb 03, 2012 1:23 pm
Hi Nigel,
Well, I guess that you know that the rubber is a closed cell Neoprene rubber, which can be brought in sheets from any larger rubber shop / dealer. These sheets were used in both the inside and outside footwells of the car and the rear firewall. The rubber makes not only a good heat insulator, but also sound as well. The downside is that the rubber holds a lot of oil and water, so when removing it, don't be surprised to find rust (hopefully not too much).
If you're really keen, I guess it could be done without removing the engine, but you would have to perform the bottom half from under the car (e.g. sides of footwells, lower rear firewall, etc). It may take longer, but one advantage is that you can check the clearances as you go (I tried using the 13mm thick rubber in most places, but went down to the 10mm rubber when clearances got too tight - with the motor out, you don't get the luxury of checking this). But, it is easier to do with the engine out, and this is what I would recommend.
To remove the old rubber, try to cut away as much as you can so that you have a pattern (if possible), then the best way to remove it all is to scrape and sand the remaining bits (remember that you'll probably have to patch some rust and seal with a water base bitumen before regluing any rubber). Cut patterns with newspaper, then cut and install the new rubber.
Another suggestion is to make sure that you seal all holes, especially around the heater box and on top of the heater box near the fresh air intake (minimises the amount of engine heat that may creep its way into the cabin).
Don't forget to do this inside the cabin in the footwells too (in fact, maybe start with this easier job - you may be happy with just this improvement). Especially the footwell ducts - make up some cones of rubber to fit inside, and this area gets so hot due to its proximity to the back of the motor. Even the exhaust at the floor of the cabin lets in quite a bit of heat, so this may be a good place to start.
Good luck,
Dino