Mar 042013

The final task to complete the heat insulation was to install the Koolmat in the cabin area. My main concern had been the ability to be able to bond the underfelt to the silicone side of the Koolmat. A number of adhesives were tested using off cuts of Koolmat and underfelt. Normal silicone sealant was found to be the best product by a considerable margin, which alleviated my fears.

However I’m now leaning towards replacing the underfelt with some 1/4″ Dynaliner when the final trim goes in. The combined thickness of the Dynaliner and Koolmat would be closer to the original bitumen sound insulation with underfelt and so there shouldn’t be clearance issues with the central console. Also the underfelt was destroyed when it was removed during the adhesive tests and so would probably cause more headaches if (when!) the trim needed lifting in future.

The Koolmat instructions suggest starting the installation with the toe box and then work backwards. I decided to do the two panels under the seats first, rather than dive straight in, as I’d not used the ALPHABOND AF178 high temperature contact adhesive before. This would provide a few easy panels to become familiar working with the adhesive before having to assume contortionist positions to install the toe box area.

Holes were cut in the Koolmat for the seat belt mounting and seat runner fittings, the latter would be screwed in place during the gluing to ensure good alignment. However, when the Kootmat panels were trial fitted, they would not lie flat on the floor as the ends of the Huck bolts for the radius arm mounting protruded above the floor pan. To overcome this an off cut of brake piping was used as a punch to cut out suitably size holes in the Koolmat, just about visible in the photo above.

The AF178 contact adhesive needs to be applied to both surfaces and then allowed to become touch dry, when it no longer lifts away when touched. The Koolmat can then be pressed in place. I chose to apply the adhesive using a brush and purchased a small wallpaper roller to apply pressure once in place, which was a good buy.

The contact adhesive certainly lives up to its name as there’s almost no opportunity to reposition the Koolmat once the two surfaces have made contact. As a result, the alignment of the first few panels was acceptable rather than perfect. I was glad I had started with the easier under-seat panels first. I then started adding alignment markers on the Koolmat and bodyshell during the trial fitting which help enormously during the final fitting, when you needed to get it right first time.

Martin Robey replacement floorpans had been fitted during the bodyshell rebuild. These are manufactured to cater for both the non-flat floor Series 1 and 2 cars and therefore have two separate sets of seat runner mounting points. The unused mounting points and floorpan holes were blanked off with short bolts and blanking grommets (9mm & 19mm) respectively to ensure the floor was watertight. I’m assuming the various floorpan holes are to provide drainage should it ever be required.

The instructions on the AF178 tin are conspicuous by their absence. I wanted to take my time and planned to install the Koolmat over several days, and therefore needed to clean the brush. The manufacturer’s ‘technical’ department wasn’t particularly helpful with their suggestion to use ‘a solvent’. I would never have thought of that! When pressed on the type of solvent, they didn’t know, and it took trial and error to determine it needed to be cellulose thinners.

I wasn’t too impressed with the accuracy of pre-cut kit supplied by Koolmat and if I were to do it again would probably purchase a roll of Koolmat and cut it from templates I made myself.

I think the person cutting the kits must have been working from memory and from a car they’d only seen once. I very much doubt they had ever fitted one of their kits!!

The issues that needed to be worked around were:

  • They suggest making incisions at each corner for the piece covering the lowered floorpan area. A much more effective way to mould it to the floorpan and avoid crumpling was to cut out narrow wedges perpendicular to the length of the floorpan as shown in the photo above.
  • They provide a piece to cover the area between the lowered floorpan and the toe box. This piece bears no resemblance to the area it is intended to cover. In the end I cut this into two small pieces for the floor, in front of and behind the lowered floorpan, and two very narrow strips to run along the outer edge.
  • From their installation photos, Koolmat simply cover over the gearbox cover. Therefore the two lower side pieces for the transmission tunnel around the gearbox were far too high and required trimming. They now finish just below the transmission/gearbox cover so the cover could be removed for maintenance.
  • The same transmission pieces overlapped the rear transmission tunnel piece by such an extent, that it was almost pointless fitting the latter.

To be fair to Koolmat, at least they provided a reasonable amount of off cuts to be able to complete the job where gaps existed.

The gluing of the Koolmat to the gearbox cover will wait until the trial fitting of the interior trim, including carpets, just in case there are issues with clearance. Finally a bead of silicone sealant was run along all the joints in the Koolmat.

Jan 202013

Several people had mentioned issues with heat soak due in the footwells due to the proximity of the exhaust. I was interested in avoiding this because I’ve had the same issue in my Elise while on long continental drives. I also remembered an article in one of the Jaguar magazine years back recommending lining the transmission tunnel with a reflective heat covering to reduce the heat coming into the cabin.

My main concern was to rebuild the car and then regret not fitting a reflective heat shield as it would be far harder to change my mind later on. Therefore, as a precautionary measure, I decided it was best to line the transmission tunnel now rather than later – probably overkill but hey ho.

After a little research into reducing exhaust heat, I went for a product from Zircotec which seemed to fit the bill. Their heat shield material comes in sheets and in three different thicknesses. The thinnest sheet should be sufficient as additional heat insulation was also being installed within the cabin. I’m glad I didn’t go for the next thickness up as I subsequently used the middle thickness Zircotec sheet to make a replacement exhaust heat shield. It would have been a little too rigid to mould to the curves of the transmission tunnel.

Paper templates were made to determine the smallest size of sheet needed (it's quite expensive!) Four pieces were required: two for the front footwell area, two for the transmission tunnel around the gearbox

Paper templates were made up to cover the transmission tunnel from the front of the footwells back to where the transmission tunnel becomes enclosed, near the handbrake. The templates could then used to determine the size of Zircotec sheet required and then to cut out once it arrived.

The installation was really helped by making accurate templates to cut out the Zircotec sheets rather than try to re-shape in-situ. I ditched the original paper ones as they were too flimsy. In the end I used the clear sticky-backed plastic sheet that was often used to cover my school books of old.

Next is the installation of the Koolmat cabin insulation ….

Jan 152013

Sound Insulation
The original sound deadening was provided by thin, perforated sheets of a bitumen type substance. I’m not sure if this is still available but there are a number of alternative products available, all of which have self-adhesive backing. Essentially all a sound deadening material does is add mass to the panel to stop or reduce its tendency to resonate. The more mass, the greater the sound deadening.

The product I decided on was Dynamat which is 1.7mm sheets of butyl rubber, covered in a metallic sliver foil to reflect heat. It normally comes in 18″ x 32″ sheets which can easily be shaped with a Stanley knife. Quite a few have used it in restorations covering the whole floor, footwell and transmission tunnel areas to stop heat soak from the engine bay into the cabin. Although I wasn’t convinced of its suitability for heat insulation and so will only be using it for sound deadening, in the following areas:

  • Door skins
  • Rear bulkhead in cabin
  • Boot floor

The only difficulty was the door skins due to the limited access. A paper template was used to obtain the shape necessary to cover the door skin, leaving an uncovered 1cm strip around the perimeter. This was to allow the waxoyl to seep as far into the door frame to door skin joint as possible.

Tapping the large flat panel under the fuel tank resulted in quit a loud drumming sound so soundproofing was added to this area The doors were quite difficult. No only just to get the Dynamat into the door space but then to remove the adhesive backing while in-situ The rear bulkheads got the same treatment. I'm still undecided whether to do the vertical panels up from the floor due to the type of trim used there

The main mistake I made was to try to cover the area high up on the leading edge of the door, above the hinge area. There’s barely enough room to get the sheet in so the backing had to be removed before it was put into position. So it naturally stuck to the surrounding areas as it was manoeuvred into place.

I’m not sure whether it is a good idea to use Dynamat on the vertical panels coming up from the floorpan as these will be trimmed with moquette, which is quite thin so the imperfections (creases) in the Dynamat may show through. I’ll decide later when I come to install the trim.

Heat Insulation
The reason why I wasn’t convinced about the Dynamat for heat insulation was that the reflective layer was innermost – ideal if you wanted to retain heat within the cabin but possibly not that effective against heat soak from the engine bay.

The Koolmat at the top is woven glass fibre covered with a grey cured silicone. Below is the type of fibrous trim backing that needs to be bonded to the silicone sideAnother product on the market is Koolmat which looked far more promising. It’s woven glass fibre covered with a grey, cured silicone layer and is designed as a barrier for conducted heat. Being quite dense, it also act as a sound deadening layer.

Koolmat is much cheaper in the US and, as luck would have it, a relative was coming over so I asked if they would be able to it back for me. I think it took up almost half of their luggage weight allowance!

The Koolmat kit for the E-Type contains 20 pre-cut pieces and some high temperature silicone sealant. The white glass fibre side is bonded to the car body with a high temperature contact adhesive and the sealant then used to seal the butt joints where two pieces meet.

A short time after, I was dropping the seat frames and centre console off at Suffolk & Turleys. They had come across Koolmat but weren’t too keen on it, as it’s difficult to get anthing to bond to cured silicone. I had a similar reaction from Andy when I dropped into Hutsons.

A comparative test was done to select the best method of bonding the trim to the Koolmat's cured silicone sideNow I was really concerned that I’d gone for the wrong product. However one of the knowledgeable folk on the E-Type forum suggested it was a good product and they didn’t have any problems.

However I wanted to make sure it would be possible to bond the underfelt to the silicone side before even considering installing the Koolmat.

The Alphabond AF178 contact adhesive simpy peeled away. This will be used to bond the Koolmat to the body but Allbond Silicone Sealant will be used on the grey side.Several phone calls later to get advice from various adhesive companies and it was time to perform a comparative test. Off-cuts of jute and Koolmat were used to test the bond for number of different adhesives and sealants.

The best by a significant margin was your standard bathroom silicone sealant! I guess that shouldn’t have been such a surprise – the only thing that sticks to silicone is silicone!

The image, above right, shows problem of bonding to silicone. It shows the test of Alphabond AF178 contact adhesive verses the eventual winner, Allbond Silicone Sealant. The Alphabond AF178 is the contact adhesive that will be used for bonding the glass fibre side of the Koolmat to the body. However when used on the silicone side, it simply peels away from the silicone. With the sealant, the bond is strong enough so the fibrous jute fails before the bond.

So a clear (rather than bathroom white!) Allbond Silicone Sealant will be used to bond the interior trim to the Koolmat. I’ll cover this at a later stage.

I’m also planning to cover the area in the engine bay around the gearbox and transmisssion tunnel with the Zircotec I heatshield material. With luck, this should reflect much of the exhaust and engine heat back into the engine bay.