Heater Box Upgrades

My 72 GT suffered from an asthmatic heater. It barely would clear the screen of condensation. The air to the floor was pretty weak as well.

The MG Owners Club offered an uprated heater matrix, a more powerful motor and a bigger fan.

I just installed the re-conditioned heater box.

It makes an amazing difference. I can set the vent control to blow a blast of air at the windscreen and have good airflow at the footwells at the same time.

To be fair-here's the condition of the system prior to the upgrade:

The insulation in the heaterbox was in good shape.
The original matrix was not plugged
The rubber heaterbox seal (the one that goes at the bottom of the unit with the two holes) was not installed (so that will affect the airflow distribution).

But, all in all, this is a significant upgrade and not stupid money to do.

Sounds great. What degree of difficulty did you have on a 1 to 5 basis?

Matt, you look awfully young to be replacing a heater matrix! :)

Let us know not only what difficulty level this upgrade was, but also what steps were involved? Did you have to remove the whole heater unit from the car to do this? PITA, I've heard, and something that would scare most people away, I imagine. Or was it possible to install the uprated parts with the heater box still in the engine bay?

Besides heater matrix, 2-speed motor, and fan, were any other parts needed?

I agree with Matt. The upgraded bits deliver the goods. Fan spins up so well I added a motor control to give it variable speeds.
The funny part is when I got the package from England and opened it up, low and behold, the motor was made in Canada. Ha! Stuck a Smiths sticker on it to give it a bit of camouflage.;)

Jim- I'd give it a three-spanner rating. The only size difference between the uprated parts is noticable on the fan itself. This requires two things for fitment.

Drew-that's my father. Us Ruch's look young for our age. Extra bits needed include replacement gaskets and heaterbox seal, new fasteners for the heaterbox make installation easier and more attractive. You may need a new ventilation control cable. If you have a one speed fan switch, and want to use both speeds on the new motor, then you'll need a new switch.

Really, that's about it. Nothing that different from any other heaterbox renovation.

Except these two things:

1-The assembled fan and motor assembly won't fit through the hole in the front of the heaterbox. You have to install the fan on the motor spindle with the front heaterbox panel between the two.

2-The fan will probably foul on the ramp inside the heaterbox. There is a little bit of wiggle room with the fan motor; if you install it at the extreme 10-o'clock postion of the front cover it may clear. Believe it or not, there is a small amount of movement with the fan, so just by locating the assembly as far away as possible from the ramp, it may be enough. If not, the tack weld at the end of the ramp needs to be broken, the ramp manipulated a wee bit, and then re-secured.

There was an article in "Enjoying MG" a couple months back that detailed the process.

The motor is a two speed unit. I had (and kept) a one speed switch. I opted to keep it this way and simply did not use the third wire on the motor. I could have installed the two-speed switch if I wanted.

I did have some drama with the heaterbox after installation of parts...it really wasn't in good shape and the flap valve fell apart after installation. So I pulled the entire assembly again. I ended up taking the new parts to the MG Owners Club near Cambridge and they installed them in a reconditioned unit for me. I then re-installed that unit. So, I guess, ultimately I cheated a little by having the pros build the heaterbox for me.