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MG MGB Technical - Heater controls
|Having forgotten which heater control mechanism went to what I did a bit of research and thankfully sorted it. However, my research showed that whilst the two mechanisms I have are both oriented in the same direction, as in the picture, some diagrams show effectively a left and a right handed layout. Paul Hunt's site shows the one I don't have if that makes sense! It would appear from this that some cars have the cables coming from opposite directions whereas in mine they both come from the right. Is this as normal as it gets with our cars?
|According to may factory parts book, you have the ones designed for a LHD car. The RHD application has everything reversed. RAY|
|That's not what I expected Ray. I was expecting to be told that one of each of RH and LH controls were the norm. Looking at the Moss pictures, not very clear I know, but it does appear as if it's one of each.|
As I said both of my cables 'approach' the controls from the right so you'd expect the 'outer' clamp to be first, on the right, with the 'inner' held in the trunion on the left. The vent control is definitely on the right side of the car so that would ideally need a 'right' handed control. I guess the heater valve cable could come in from the left if I'd run it that way but I'm pretty sure it's the way it was when I took it out over 5 years ago. Mind you, the old grey cells are not that clear about what happened yesterday let alone 5 years ago!
Thanks for the thought.
|Drawings and even photos can only be considered to be representational, IMO. I don't really see why LHD should be different to RHD in terms of which 'hand' the dash control is, unless the direction for 'on' was different to RHD - the flaps and taps were the same on both cars. However the part numbers are certainly different. The orientation of the RHD heat control changed from illogical to logical with rubber bumpers, for North America there were three heat controls and four air by the start of the 1971 model year. The part numbers changed again for the 77 model year, but all markets then seem to have used the same ones.|
My 73 has the cable exiting the control in the same direction for both controls i.e. towards the centre of the car. It is this which gave rise to the illogicality, as the air flap cable has to be pulled to open it with a logical anti-clockwise movement, whereas the heat control has to be pushed which needs the illogical clockwise movement. My 75 V8 has the air control as before but the heat control with the cable exiting in the opposite direction, which 'corrected' it, i.e. turning the knob anti-clockwise now pushes the cable instead of pulling it.
So I would say for a UK CB car both controls should be the same hand, as Richards image, but they are still different part numbers for other reasons such as the relative angles. For a UK RB car the controls are handed differently.
|Suddenly remembered the Gaydon cut-away. This is a CB LHD, probably 65, and shows the controls with the opposite orientation to Richard's, i.e. with Richard's anti-clockwise pulls the cable whereas on the Gaydon car anti-clockwise pushes it. *If* LHD were indeed opposite to RHD then Richard has the correct ones. But there again the one I show is the same as the Gaydon LHD. But I can't remember where that came from so it isn't a lot of help, orientation wise.|
The crucial thing is, on a LHD CB car, do you turn the controls clockwise or anti-clockwise to turn on the air and the heat?
|<<The crucial thing is, on a LHD CB car, do you turn the controls clockwise or anti-clockwise to turn on the air and the heat?>>|
Certainly on the metal dash cars, the knobs would have the same part numbers if the direction was the same as RHD.
I dismantled an early RHD dash recently and the controls both pointed the same way - I can't remember which way without looking.
My '67 was originally LHD but I don't know whether the original controls were retained when it was converted. Again, I will have to check the orientation.
|Paul's correct. My two controls have differing part numbers stamped on them because the initial angle of the moving cable clamp is different. Looks like we all agree then. You get what you get and as long, and as the relevant parts move in the required direction it doesn't really matter...saving Paul's observation of how illogical things are of course.|
|At the top in the attached are my 73 controls - 3/366 for the heat and 3/347 for the air, of the same orientation but different angles. At the bottom my 75 - 3/533 for the heat and 3/347 (again) for the air, of different orientations as well as angles. FWIW in both cases the heat cable inner is solid and the air stranded.
|Same as mine Paul, a 72 Roadster. Well at least there is something in common.|
|Paul, On my '67 LHD car, the heat and air are turned on by rotating the control knobs counter-clockwise. RAY|
|Both of my sets are as above photos.|
|They obviously 'logicalised' the LHD heat a long time before the RHD, then :o)|
This thread was discussed between 12/01/2012 and 16/01/2012
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