Boot Floor Sound Deadening

Does the Flintkote sound deadening material used the the boot of Ser I coupes go under the gas tank, and if so how far?

On my S 1 1/2 it went all the way under the tank to where the floor starts sloping up. The tank had glued itself to the stuff in one spot and was damned difficult to loosen and take out.

On my early 4.2 FHC it went behind the seats, up the ramp and stopped at the transition to horizontal.
From there it was a white crackly material and then nothing at all in the tank cavity other than a soggy matt the tank sat on.

Boot/tank cavity:

Rick OBrien
65 FHC in FL

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I had the same stuff on my 65 Rick. I ripped what I could out and put that dynamat all around best I could.

So are folks recommending Dynamat under the gas tank as well? Any experience? does it make it harder (more so than normal) to get the tank back in?

Whatever you put in there will certainly affect the installation and fitment of the tank. I would certainly do a test fit of the tank with no product and get an idea of how much space you have to deal with. To some extent, the tank “hangs” from the 4 attachment bolts so some gap is plausible. I just don’t know how much and it would vary from car to car and tank to tank.

I slipped a plastic bag under the gas tank and filled it with spray foam. This way you get a perfect support with nothing sticking


Brilliant idea! Plus 20 insulations.

I took two sheets of sound deadner and stuck together and just slipped underneath so it could be removed. I used closed cell style stick on sound insulation for the rest so it will not absorb fuel or odor. The thicker dynapad could also be removed at any time.

Thanks gentlemen. I’m having the boot floor replaced in my coupe. I’m using a 3M product 08840 which are sound deadening pads. They are some type of bitumen like product, sticky on the back, have a diamond pattern on the surface that is similar to the original Flintcote but is a bit more aggressive. They are fairly hard. I don’t like using Dyna Mat on the floor as the foil is easily damaged, and they develop dents etc from being so soft.

Terry, I like the 3M product you recommended, from an appearance standpoint. Any experience with lingering odor as the product off gases?

Harvey - it has no smell that I can detect. It’s cool here but I think it’s odorless. I’ve only been working with it for a few days. If you want to paint it you remove a clear plastic coating on top, but even then no smell. We’re planning on painting it.

would like to see pics.

Are you painting it to be concours correct? I think mine were originally painted over.

Hi Bill - should be done and available for pix in about a week. I’m not trying for concours authenticity but I like to keep it close. I like the quietness of the coupe so I decided to redo the deadening. This is the only product I thought acceptable - that it somewhat resembles the stock material is more a happy coincidence.

I used a similar product, no issues. Once you run a roller over it to bond it to the boot floor it’s only about an eighth of an inch thick. I also left the rust promoting pad off of the underside of the tank.

James I think you will have a significant problem with water getting between the floor and the coating you’ve installed. The rear of these cars is seldom water proof.

I agree, it’s all removable though, and is closed cell foam, so it doesn’t absorb the water.
We do drive the car in the rain so I can expect there to be some water leakage. The drains are important. There is one just below the fuel tank.
I remember the first time my lady and I got the E type from CA to FL we were driving local and got caught in a rainstorm. We may as well had the windows down. Haha they sure as hell aren’t very weather tight.

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Hi Bill Photos of the finished boot with the 3M sound dealing. It’s appearance as it relates to original is: “Close enough for government work” as they say.

IMG_8957 IMG_8956


That looks way to nice to clutter up with a spare tire.

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I can’t find it listed anywhere but 10 sheet quantities.
Had I seen this stuff I would not have bought a roll of the shiny stuff.