Heater rebuild

[Robbie693]

Hi,

I know this has been discussed a few times but I can't find an answer to my specific questions about the materials required to refurbish my Plus 2 heater.

I found this site which may be useful for the bits:

http://www.smfoam.co.uk/index.html

Problem is I don't know what kind/size of foam I need.

Firstly, should I use an open or closed cell type for the flaps and around the matrix?

Also, what thickness would be required for wrapping around the matrix?

From what I have gleaned from the archives, a foam strip about 3mm thick would be about right around the flaps but what kind of width will I need?

I'm asking this in advance - I haven't got the heater unit out yet (still removing the dash) so apologies if I'm asking stuff that's obvious when it's apart

Cheers

Robbie

[kcrossle]

You're doing this the right way - asking first... instead of my approach: rip out the old then wonder what it should be. Note - I was concurrenty removing some sort of beast's nest so that is some excuse. I seem to remember the foam being similar to the weatherstripping you can buy for doors and windows. Just a bit wider maybe (3/4"?).

Looking forward to authoritative replies... or what you discover when you get to it (please hurry I'd like to put the heater back in this weekend

[carrierdave]

Hi Robbie/Keith,
I used closed cell foam for the damper blades, approx 2 to 3 mm thick (From Wollies trim). The reasoning behind this was open cell will tend to collect more dust than the closed cell type.

From memory the damper blades are around 12 inches long by 6 inches wide. The very bottom damper blade then has 3 lengths of runner seal, riveted onto the bottom face of the blade.
This provides a bottom seal around the blade to stop leakage when you are demisting. If yours is like mine, then this seal will be brittle and fall apart when you touch it. I used the same closed cell foam to replace this; alternatively you will need to find some rubber of about 1mm thick.

The matrix we held in with open cell foam, this was attached to all four sides. You would need foam that will compact very well so open foam of around half an inch thick would work. The matrix is around 12?x 5? so you won?t need a great deal.

Dave

[Robbie693]

Well I've got this stuff, approx 3mm thick by 25mm wide. It's not very compressible compared to sponge, will it do the trick?

I wonder about how compressible it should be to achieve a good seal...

[carrierdave]

To be honest the words ?Lotus heater box? and good seal don?t go together in the same sentence!!

From what I could see, the only reason for the foam on the damper is to stop the damper banging against the flange.

The top damper has the foam on the bottom face and the lower damper has the foam on the top face - both of these cushion the damper when it hits the frame edge.

The only true seal is the rubber edging along the edge of the bottom damper.

The best thing to do is try the material on the damper ? personally it looks fine.

Dave

[Robbie693]

Thanks Dave, will do.

I'll report back when I've got the heater out and apart

[Jason1]

Hi

On a sort of related topic my new heater knobs just arrived in the post from SJ Sportscars. The original one is on the left and the new one is on the right, I think they are ok for ?3.50 +vat each.

I have been looking for ages for these as mine are a shabby.

Jason

Ps
I have nothing to do with SJ

[handi_andi]

Thanks Jason, I need at least one as one of mine has snapped and wondered where they could be sourced from.

On the foam subject, personally I would always go for closed cell foam as open cell will soak up moisture like a sponge.

Cheers

Andrew

[kcrossle]

Hmm - here's my heater and you can see remnants of the seal around the "flap". Is there a 'mating' seal around the whole opening? Inside.. in the middle position maybe? Or is it just the seal illustrated here?

(Reminder - always take pictures upon dis-assembling things!)

Thanks

[kcrossle]

Better illustration of existing seal in yellow

[kcrossle]

One more note on this topic... it struck me as rather odd that we are discussing a '60s English car and its Heater... an oxymoron to many. Reminds me of my TR4A in New England in the '70s. I would drive to NJ from MA at night each weekend in winter. Lights, wipers, heater. Choose one and a bit.

[handi_andi]

Ah the electrics of a TR4 where you can choose slow or slower with the wipers due to the use of a heater fan style resistor was used to give the two speeds.

Should this saying also be applied to an Elan heater, cool or cooler perhaps?

Andy

[carrierdave]

Hi Keith ? Yes the one indicated is the only true seal in the heater box. It basically either seals against the lower edge, allowing hot air to your feet or is in the upper position to direct the air to the demist vents.

On the inner face of this damper you will find the remnants of a foam gasket. This closes against a raised opening on the discharge side of the coil.

When you take the side panel off all will become clear.

[msd1107]

The Elan heater was just fine as long as you remember heat output was basically dependent on throttle position and to a lesser amount on how far the knob was pulled out.

So fast or up hill was fine, but going down hill you froze your butt off!

And if you were unlucky, you got the heater working in the summer time no matter how you pushed in the knob. Best to go into the engine bay with a screwdriver and manually close the valve.

[Robbie693]

Thanks for the replys so far, Sorry Kcrossle - didn't manage it by the weekend

Update - need more help..

Got the heater out and the side cover off. The foam is disentegrating so definitley needs replacing. The bottom flap rubber seals aren't too bad - bit of a tear in one though (see pics). I may try and stick some of the closed cell foam I have to the rubber blades for extra sealing... The matrix foam is in good condition and looks like it has been replaced at some point.

I can see what Dave meant about sealing being an alien concept to the Smiths heater - there are gaps everywhere!

The outlets for the side vents are completely unsealed and a really bad fit, maybe some open cell sponge around here will help?

Now to my next questions:

How do I get the flaps out of the casing? Do the levers on the ends come off the rods?

Also, can someone tell me how the control levers should be installed in the dash? The picture shows how it was installed in my car but I believe it is the wrong way up as there is a detent for the middle position in the top lever (hot/cold) which I would have thought would be for the screen defrost position..

If I turn the thing over then the cables will be going to the right before bending round to the heater where they attach on the left. Will they fit like this?

The manual shows the controls installed as mine were - how's yours?