Morris Minor - heater installation

Symptoms of problem :  Freezing cold - no heater fitted to vehicle since 1957 !!

Vehicle : 1957 Morris Minor 1000 Pick-up (LCV) - a CKD MM built in Petone, New Zealand. (part Series II, part Minor 1000 I think!)

Time : 4 hours   Difficulty : 4/10   Parts required : Heater, heater tap, gasket for heater tap (or gasket paper), radiator with bottom pipe fitting for heater hose (or bottom hose with side branch and a short length of half-inch metal tube), length of half-inch heater hose, 4 x jubilee clips, bowden cable and lever for control of heater valve.  Cost : approx. 30

Special tools required :  Nil

Here in New Zealand, heaters were not fitted as standard, despite the fact that the temperature in many parts of the country drops to zero or just below often during the winter. On this particular MM, a 'Ute' (Utility vehicle = Pick-up) the passenger seat was also an optional extra, believe it or not ! There are several types of heater available locally secondhand, so I chose to fit the type that was originally intended - a rectangular unit manufactured here in Wellington, N.Z.  Also available is the round style of heater which will be more familiar to British readers. They both have little doors that open to direct heat downwards and 2 outlets for connection by narrow ducting to the windscreen demister slots.  

At the rear of the heater unit, hot water in/out connections are via 1/2" rubber pipes through the firewall to the engine cooling system. On the 1098cc engine fitted to this particular vehicle (non-original, it probably was a 948cc or maybe even a feeble 805cc?) there is a metal blanking plate at the back left of the cylinder head where the heater hot water take-off and control tap or cable-driven valve is fitted. Cooler water from the heater is returned to the bottom of the radiator - either by using a special bottom hose with a side branch (a short  length of half-inch metal tube allows connection of the rubber heater hose) or to a metal access hose at the base of that type of radiator. The latter method is preferable (although I had to buy a secondhand radiator of this type) because it allows the rubber hoses to be shorter and run more neatly in the engine compartment - the 'side-branch' method means routing a heater hose across the top of the engine and down to the bottom hose on the right hand side of the radiator.

radiator   heater valve

                       Radiator heater return fitting - lower LHS                                                Hole in cylinder head for heater tap

Electrical connections to the heater are simple - there is a single-speed fan (although the fan speed could be switched or controlled electronically very easily) so only a FAN ON/OFF switch is required. 

firewall    

Threaded lugs and large grommet in firewall for fitting of special NZ-made heater unit

heater 1

                        Special NZ-made heater unit

I don't have either of the (metal I think) special fittings which connect to the windscreen demisters. If I'm really stuck I'll try modifying the similarly-shaped plastic pipe-end fittings you get with vacuum cleaners !

Many of these early heaters were 'recirculating' i.e. not 'fresh-air'. As you can see in the photo above, there is a large rubber blanking grommet in the firewall to allow fresh air to reach this type of heater - via the gap behind the battery - but I'm hesitating about removing this grommet because MM owners tell me that it means you have to keep the heater ON all the time to compensate for the cold air rushing in here. I'll see how 'recirculating' works in terms of how much fresh air is needed from the windows, before deciding about this. I'll also need to figure out how to move the Bowden cable which will open/close the heater control valve.

heater 2

The photo above shows the heater installed in position, but with the demister pipes still to connect.  The fan is connected via a toggle switch mounted under the speedo to the main fuse - the group of green wires which are fed with +12v when the ignition switch is 'ON'. This fan is not as noisy as the fan fitted to the 'round' type of heater.

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