foam trim under hood?

[lotusdelta]

I was looking at the pic of the plus2 for sale and saw the foam strips under the hood and it reminded me to inquire, what this is for?

Does it make a better seal to force more air into the radiator?

My Spint Coupe was sans foam when i bought it and wonder if I should add it.
Can i just cut a strip of foam or do i have to order a spcific piece?
Thanks,
david
72 elan sprint coupe

[elanbaby]

Hi David,
yes, it?s purpose is to force air through the radiator than rather let it take the easy way above.
As far as I know this item is not available anymore, but it shouldn?t be too complicated to cut some foam to size.
Juergen

[trw99]

The strips are available still from Susan Miller at ?3.95 + VAT. She also does the thin foam strip that runs along the top of the engine to bonnet (hood) closure closest to the windscreen.

Tim

[lotusdelta]

Thanks for the reply....I;ll probably just cut a piece of foam to fit...

any issues with the foam getting hot?...

also , any ideas as to what source I can use to locate the exact spot to fit or should I just eyeball it..

Thanks, David

[trw99]

David

The foam strip is in two sections. The longer foam strip, glued to the bonnet (hood), sits along the top of the radiator. There is a gap for the radiator filler cap and then the shorter strip fits on the other side (carbs side) of the radiator top. Hope that is clear!

Tim

[elanbaby]

Here?s a picture how the foam looks when glued to the bonnet.
It?s not my Elan and I can?t remember who it belongs to. I took the picture at Donington and the owner may forgive me.
Juergen

[kayenney]

If you look closely of the photo of the +2 for sale, you will notice that there is also a strip of clear perspex running across the width of the engine bay that the foam seats on when the hood/bonnet is closed. If this is not clear, let me know and I will try to take a photo that shows it better.

Ken

[lotusdelta]

Ken,
Thanks for the photo, it shows the placement perfectly..appreciate the effort,
david

[denicholls2]

Any hardware store or the evil Wal-Mart will have foam used to seal air conditioners in windows (seal the partly open window). It's about an inch thick and is great for this application, usually around a dollar.

[DJThom]

I work in R&D for the world's largest automotive polyurethane suppliers. When you sandwich foam between the rad and hood, you are essentially simulating one of the standard tests we do, known as compression sets.

In this test, foam is compressed 50 or 75% at 70 degrees C for 22 hours, relaxed for 30 minutes. The thickness is measured before and after. The objective is to measure permanent deformation, which would degrade the seal between the rad and the foam over time by destroying the foams ability to "spring" up against the rad.

There is a huge discrepency in performance in this test between foams, and it is exaggerated by humidity.

Not only is there recovery issues, but airflow issues. You want air to go to the rad, not though the foam.

Thus, I would not suggest a cheap foam. I would suggest a high density (greater than 2.5 pound per cubic foot pcf) to minimise permanent distortion which would give a bad seal, and a semi-closed foam such that air can not penetrate as easily and is forced through the rad.

Suggestion would be to find one of these small companies that make mattresses. They should be able to give you an offcut of some sort that met at least one of the suggested criteria. You can blow on the foam to get an idea of airflow. There is quite a difference from grade to grade.

[stuartgb100]

I've just gone through the process of adding some sort of barrier above the radiator, but took a different approach.

I used offcuts of felt (the sort used for sound insulation under the car's carpets) stuck on with contact adhesive. Then painted them with matt black paint to match the underside of the bonnet/hood.

Looks good, but no idea how efficient it will be !!!

Regards,
Stuart.

[DJThom]

Probably better than foam.

I don't understand how you have room for anything. My rad is nearly hard into the bonnet,and I've already drilled new mounting points to bring it back as far as possible. I can barely get the rad cap off!!!

[lotusdelta]

Hey stuart,

I've got some of that stuff left over from being used as an underlayment under carpeting in the trunk...(boot)...I agree it might be just the right stuff......but will it get hot?
Thanks, david

[stuartgb100]

Yes, I guess it will get hot, but I figure it's relative ....... a radiator header is not THAT hot after all .

I'll know better after the weekend. If our weather doesn't let up then I'll run it in the garage for a while.

As regards the gap ........... there's not that much to start with!
I've a single half inch thickness of felt each side of the rad filler cap, and then another single thickness to take up the curve of the bonnet.

Regards,
Stuart.

[stuartgb100]

Meant to add that I fitted one thickness first, then closed the hood/bonnet and ran it up to temperature. When it cooled, I opened the bonnet and could clearly see the impression in the felt where contact with the rad header had been made.

Simply added the second layer, where necessary, to fill the gaps.

Will try and post a picture if that doesn't make sense.

Regards,
Stuart.