heat insulation - interior

[NutmegCT]

I did a forum search here on "insulation" and found many references to sound insulation (Fatmax, Dynamax, etc.).

I'm much more interested in lessening the engine heat radiating into the interior through the floors and firewall; sound proofing I could care less about. Fatmax and Dynamax are advertised for sound deadening, not for use against heat.

I just put Reflectix heat insulation under the carpets of TeeYah. A "profound" improvement on the heat transferance problem I had. Didn't glue it - just cut and laid down under the carpeting (including floorpan area, transmission hump and firewall).

Which "under carpet" heat insulation products are you guys using (if any)?

Thanks.
Tom
PS - here's a sample of Reflectix: like foil enclosed bubble wrap.

 

[Harry_Ward]

Tom,

I'm using a similar heat reflective material about 3/4 inch thick, taped all the seams with furnace flue pipe tape, but unfortunately cannot recall the product name. It was purchased at a local hardware store owned by a GTO gear head who also uses it. Works OK (not great) on a poor mans budget. The main thing I've found to keep the 3 cool inside in the summer is to turn that heater valve off! Even with the heater rheostat switch off and the heater doors shut that little heater radiator circulates the hot stuff real well. I use to leave the valve open because I thought the engine would overheat quicker with the valve closed but this summer has proved that theory wrong. So now I have the valve shut. Don't you know though the wife now complains it's too cold at night with the heat off. I just can't win. At least the valve gets exercised more often and maybe wont seize up.

 

[TR3driver]

I had a similar product, but with synthetic felt rather than "bubble wrap". There's also some sort of fiber bonded to one side, for strength. Bought it at a swap meet, but I've seen the exact same thing in Home Depot sold as "water heater insulation". Worked quite well for both heat and sound; I'll be using in the project TR3 as well.

Heater ? What heater ?

 

[MGTF1250Dave]

Aloha Tom,

I have a piece of thick felt like carpet padding that I shaped to fit over the gearbox cover. I got it at a carpet shore, the guy gave me a piece of scrap. I used duct tape to hold it in the shape. It seems to work for me in reducing both noise and heat. A carpet shop guy gave me it I think most of the heat, at least on the drivers side comes from the gear box. The passenger side might be warmer from the exhaust system, but I never ride on that side.

 

[Aldwyn]

Anyone try the stuff Moss sells? Ironically, I just ordered a sheet with an order I placed last night!

 

[TR6oldtimer]

IMO, the original jute under felt provided a sufficient sound and heat barrier, especially if covered with the wool carpet. It also made a great sponge every time it rained.

 

[Geo Hahn]

I too use a felt-like material with the foil stuff on one side. I found it at a local auto-upholstery supplier. They sell to the trade but also take walk-in retail.

I think one key point for heat resistance is to have the foil side towards the heat source (i.e. down).

The original jute may be okay for some but I was getting complaints about the heat from my passenger... perhaps because her feet (in a 4-cylinder TR) are directly above the exhaust pipe.

 

[ALLAN]

I think one key point for heat resistance is to have the foil side towards the heat source (i.e. down).
[/quote]




I posted this question about 1 year ago as I had originally installed mine with the foil down, but the greater majority of responses said not to install down because of rust issues.

I am now going with Raam-mat which in independent testing came out rated higher than the original Dynamat at a better price. With most of the commercial sound deadeners the foil goes up. Even though they are primarily for sound deadening according to most reports they are very good at stopping the heat.--------here is the testing and ratings that have been posted here before, https://www.sounddeadenershowdown.com

 

[Guest]

The rust issue that you alluded to is not that the foil surface itself will rust but that the foil material will have a tendency to abrade the painted surface on the floor board and moisture will eventually start the rust problem on the steel floor board.

 

[ALLAN]

Good point Bill, also when I pulled my old insulation up (with the foil down) it was hard to remove and some of the foil had embedded into the paint--pulling up some the paint with it.

 

[Scott_Hower]

I bought some reflective firewall insulation from Aircraft Spruce. Silver on one side, dense and foamy and sticky on the other.
About 2" wide strips, wasn't sheap, but works great.

 

[TR674]

Bill
it is more to do with contact between dis-similar metals. I specify similar products for roof/ceiling insulation in buildings. If any of the insulation foil (shiny side) comes in contact with a sheet metal roof, corrosion will occur and warranties are void. Always keep the foil side away from metal, painted or not. There is also a foil with paper covering both sides to avoid metal contact.
Try looking thru building insulation products.
Regards
Craig

 

[NickMorgan]

I think I will buy some Reflectix to wrap myself up in when I take the TR out for a drive. It just never gets hot enough here to need to keep the heat out of the car!

 

[NutmegCT]

I think I will buy some Reflectix to wrap myself up in when I take the TR out for a drive. It just never gets hot enough here to need to keep the heat out of the car!

envy envy envy

Reading all these comments has been very interesting. I would never have thought about the "metal to metal" friction leading to eventual corrosion, altho' I'd think that the multiple coats of POR15 I put on the sheet metal would delay that.

Hottest part of the car is the area just around the shifter, which of course is the area tight against the bases of the seats. Tough to get anything down there that isn't compressed very very thin.

I realize that sound insulation materials would provide some heat insulation properties. However, that sound deadener comparison website doesn't compare heat insulation properties at all - only resistance to heat damage of the product itself.

Thanks all.
Tom

 

[TR3driver]

I think one key point for heat resistance is to have the foil side towards the heat source (i.e. down).

Might make a small difference, but mine seemed to work well with the foil up.

I think the only difference would be reflecting the radiant heat (infrared light) coming off the floorboards; and with the padding in contact, I imagine most of the heat is conducted. If it did reflect any significant amount of radiant heat, it would just make the floorboards hotter and so conduct more heat anyway.

 

[YankeeTR]

I try to use Dynamat. You can buy it quite inexpensively at swap meets for about 40 less than you see advertised. The last time I bought it I got enough to do a '55 ford pick-up floor and back wall for about $40.00.

I've also used the 'bubble wrap' product...works good but I don't like the way it installs...

 

[RonMacPherson]

EXACTAMUNDO!

 

[mrv8q]

There's also some sort of fiber bonded to one side, for strength. Bought it at a swap meet, but I've seen the exact same thing in Home Depot sold as "water heater insulation".

Just this weekend, I went to Home Despot, looking for Randall's Water Heater Insulation kit. I insulated my water heater about 4 years ago, and really liked the stuff, but couldn't find the exact match. Looking around, I wound up with Frost King Duct Insulation: Self-adhesive Foil and Foam.

This had an insulation rating of 3.0, where the much thicker water-heater stuff had a 3.5 rating. I think this stuff is OK to use on the plastic of the TR6 replacement tunnel; not so sure about using it on the metal floor of a TR. Not too hard to attach to the 6's tunnel; but I wish I had done this before I put the tunnel in. A couple trims w/ scissors, and I taped the ends with left-over water heater tape from 4 years ago... ( and a couple small nicks from the metal-foil cover).

This stuff is 12 inches wide, 1/8 inch thick, and 15 feet long, and cost about $17. I've got enough left to cover most of the TR3's metal tunnel cover, if I'm so inclined...

I've yet to road test this however....

 

[DNK]

Hey, is your 6 Brown?

 

[NutmegCT]

Kevin - I'm very interested in how well your tunnel installation holds down the heat. Please keep us posted on after some road time in sunny LA.

Another thing that intrigues me is how well "compressed" thicker insulation works, compared to the non-compressed thinner stuff. If I put 2" thick insulation over the tunnel, it gets compressed down to about 3/4 inch under the carpet. And most insulation instructions say something like "compressing insulation greatly reduces effectiveness".

Thanks.
Tom