Let there be light – dipping headlamps

It was interesting to find that the Riley has the King of the Road ‘dipping’ headlamps. These are 9″ in diameter, enormous chrome bowl things with genuine silver reflectors. But thats not the interesting part – the dipping feature refers to a solenoid operated mechanism that literally tilts the reflector downwards when operated. The solenoid is quite clever in that once operated it switches to a separate winding so that it draws only a small amount of power. That is pretty important when you remember that these cars only had a slow running (and noticeably poor by modern standards) dynamo to charge the battery with.

Oh and the other thing is that only the nearside headlamp dips, the drivers side one is turned off when in the ‘dipped’ mode. So that means just one headlamp is on at that moment. I imagine that meant quite a few accidents  so this is now illegal (spoilsports). So somehow I have to find another dipping headlamp or some way of modifying the offside headlamp to house a dual filament bulb.

The silvered bowls are in…. an okay condition, the silver cleaned up so that you can see your reflection but i can see it is only a micron thick coating because it is dead easy to polish through to the brass. Luckily it is not expensive to have them replaced but thats a job for another day once i see if I actually use the car in the dark…

Naturally getting the headlamps to work is a serial restoration project – the switch to operate the dipping mechanism is mechanical and sits on the end of a number of rotating shafts that run down the centre of the steering wheel. Putting an electrical meter across all the contacts i could see resulted in my realising that none of the Rotax switch mechanism worked (no surprise!). But how to get the switch off the steering column… much head scratching followed before deciding that i would take the electrical part off the steering column first and take a look at that. Naturally i had no idea how that came off either but the tactic i have learned is to look at things from all angles – loosen screws that ‘appear’ to retaining something and giving the item a wiggle and see if it moves. It took me a while but eventually i worked it out. Weirdly I now know how these things work and will probably always remember how to remove it again. Interestingly once the electrical part was removed I could see that all the tube mechanisms were now also free and they simply pushed up the steering column and out the top.

The electrical switch is fairly simple – it is basically a cylinder with a number of which flat brass ridges that run in short lengths around it. The lever on the steering column rotates the cylinder bringing it into contact with various brass contacts, each of which have a separate purpose. Luckily under the thick grease were some letters that were fairly obvious in their meaning. I degreased the cylinder, cleaned up all the brass contacts and shot blasted the brackets, cylinder and the brass cover.

In the picture below, the switch mechanism is remounted on the steering column controls so that i could test it. You can also see the brass cover. The wires come out of the end of the tube are for the indicators and are controlled from a bakelite switch also in the centre of the steering wheel. I would like to keep all these features because its quite a nice thing to retain.

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I had to put back some tension into the brass contacts but now the electro mechanical with works again so its onto the headlamp solenoid…

In the picture below you can see the mechanism bolted to the back of the headlamp bowl. It looks like there is supposed to be a fuse also mounted to it. I will temporarily place one there but will rebuild it so that the fuse is actually in the cockpit and not inside the lamp itself. In the photo at about 8 o’clock you can see one of the 2 hinge pins. The entire headlamp bowl rotates on those with maybe about 1cm of movement. It moves quite freely and I can see what ‘should’ happen. The solenoid is bolted to the frame and when electronically operated, it will drive a pin against a solid bracket, effectively pushing itself and the headlamp bowl away from the bracket forcing it to rotate around the pivot. Easy. I just need to get the solenoid working then. Luckily I found a wiring diagram on the intraweb that told me what all the terminals were for so I could put 12 volts in the right places. A good clean of all the sprung contacts and little bit of lubrication inside the solenoid for the shaft meant I soon had it working again. Naturally I will be replacing all the grotty pieces of wire with a more modern substitute

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This is the front side of the headlamp bowl.

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The lamps I will replace with LED bulbs primarily because they consume significantly less power than real light bulbs and they are also much brighter and I suspect i will need as much light as i can get…


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