Original heater matrix and box

[Doc Watson]

I have it on good authority that the original Mk I cars had a 'modified' heater box from a MK I ford cortina car. Can anybody confirm this? if so what modifications are required.

It would be logical to assume that the original matrix and fan was retained and the modification was on the 'fan box' shape and the vents which come from it.

I've found an old exploded view of the item in question (not from a GT40 but the same heater).

The reason I ask is because I now own one of these and plan to put it on my car, routing the water from the 'cow horns' (look at an original engine water outlet pipe) through the central spine to the heater and back to the water pump with one of the water pump outlets blanked off. This keeps all the hot pipes in one place and also alows 'instant' heat as the water takeoff point will not be in a part of the circuit which is controlled by a thermostat. (Do the original cars have a thermostat to prevent water flowing through the radiator on engine start-up???)

BTW it cost £4.99 !!!!

Andy

 

Heres an over all view of MK 1,
don't know if this will help ???

 

[Doc Watson]

Not quite original but 1960's.... Picked up this sorry looking article and applied elbow grease... will get zinc primer and then gloss black once its all clean. Will need to wait for the chassis to fabricate correct sized plenum chamber that it sits on.

Andy

 

[Doc Watson]

Forgot to mention its from a Land Rover Series II. The original box sucked air through the fan and out the sides of the box. The 'flip' sides on the box were used to provide crude airflow, basically left, right or both!!!.

The GT40 conversion will suck air through the side via filtered grills (to be made) and blow hot air out the fan hole into a custom made plenum.

The plenum will have 2 ducts to the windscreen grill and a butterfly valve allowing feet warming.

 

[marcel]

Hello Andy

I am quite often looking to your detailed investigations. What I really like, is, that you pay attention to the details. So, that's important for me too.

Would be helpfull if we could talk or write once about several details, cause you already did severel steps I still have (and also would like) to do.

As I understand (sorry for my english), you will take the heater from the Land Rover 2. Do you have any suggestions for the "panel" ? Of course it is under the dash. Did you took also this one from the Landy ?

Regards from Switzerland Marcel.

 

[John W]

Andy, that is a standard smiths part, used on a number of cars.
It can be found on things such as Reliant Robins, Land Rovers, etc.
The lotus 7 used to use this heater too.

The water flow was controlled using a seperate valve in one of the flow pipes, not via a thermostat.
Hope that helps.

 

[JimmyMac]

John,
You are incorrect.
The water temperature was controlled via a Ranco thermostat valve and the the heater was made especially for the GT.
Those applications which you mentioned appear similar, however on the real one the air is moved through the bottom of the heater through an iris vent to a double plenum and not simply by the side doors as in the Land Rover.
The fan motor is fitted lower and the heater coil matrix inside is also different.

 

[John W]

Really ?
I can't say for sure on all your points, but can tell you the heater on my friends Lotus is exactly the same as the GT40 one, and the heater in my Caterham is almost identical too (has an extra braket on it similar to in the above picture for the control valve, but long since cut off).

Does the above have a single or dual speed motor ? (looks to be single to me)
There are two types with differing dimensions, the two speed being longer...
Its over 20 years since I fitted this heater in the Caterham (time flies !), so appologies if I have it wrong. There will not be a heater in my 40, unless you include the FE lump in the back

 

[JimmyMac]

John,
Indeed, the early Super 7 cars had a Smiths heater unit almost the same as the GT40.
This is where I got my first heater from. However, it did not have the Ranco, nor the bottom vented air box and the plumbing layout was different.
The air box rivetted to the heater and the plenum were from Len Bailey's pencil.

 

[John W]

Okay ,happy to be corrected on this. It seems funny that I actually cut that bracket off my box when I got it. Ho hum...
That valve on mine was cable controlled though, not thermostatically. Its now replaced by a plastic bodied cable operated valve in the feed pipe.

Your right though, it definitely didn't have the round closing vent on the underneath as in your picture. I had assumed that was part of the gt40 hatch.

 

[JimmyMac]

John,
Agreed. They obviously custom made the complete assembly using available parts from the Smiths catalogue.
See the photo of a spare bottom vent plate.
The main plenum box covering the heater is also an integral part, I have one at the workshop but can't find a photo of it presently.