While I was in the midst of body work I needed a change of pace so I decided to rebuild the Riley's generator. My first step was to determine what generator I had. This was easy, the model number is stamped on the case. I had a Lucas C45PV5. This is a common generator used in many 1950s British automobiles. The date of manufacture was March 1952. I assume it is the original generator for the car.
I started disassembly by removing the metal band that covers the openings in the rear of the generator. With this removed I could see the brushes and the commutator copper. The brushes were a little worn but everything else looked ok. It was pretty grimy in there. I disassembled the rest of the generator so I could clean it. The rear aluminum end plate came off after removing two long machine screws. In the front I needed to remove the pulley and fan. I used a impact air wrench to undo the nut. The pulley and fan then were removed easily. The shaft key was hard to remove and by the time it was out it was mangled by the Vicegrip I used to grab it. I replaced the key, it is a standard half moon shaped 1/8 in x 5/8 . Now I was able to withdraw the front cover from the shaft. The front cover has a bearing while the rear has a bronze bushing. The bearing takes considerable load especially if the fan belt is over tightened. To remove the bearing I drilled out the 3 rivets that hold its retaining plate. The bearing is a standard size 17mm X 40mm X 12mm. I used a double shielded type as opposed to the open original. To reinstall I made rivets from a #8 machine screws. I was going to use these fasteners with nuts but the nuts would have interfered with the fan. To use the machine screws as rivets I cut them about 1/8 inch long supported the head on my vice an hit the other end with a small hammer peening the ends over.
While examining the generator case and field coils I noticed the cotton wrapping on the coils had broken down and was crumbling off. Thank goodness, in a recent RMemoranda there was an article about rewrapping some starter field coils, this gave me the confidence to try the same thing with my generator. First I had to remove the coils. They are held in place by two large phillips head machine screws. The manual shows a rather elaborate rig to remove them. It takes great downward pressure to prevent the heads from stripping while applying the necessary torque to loosen them. I decided to cheat. I used my air impact wrench with a large phillips bit. It took several attempts and a very slight amount of heat but they came undone. I looked around the house in the sewing supplies and found some binding tape in a nice shade of baby blue. I wrapped the field coils in this and gave them a light coat of varnish to hold everything together.
The case pulley and fan were sandblasted and powder coated black. The aluminum front and rear plates were cleaned on a wire brush. The mounting holes in these plates were elongated by years of vibration and use. I drilled them slightly oversize and press fit a thin wall stainless tube to restore them to the correct size. The bushing on the rear plate was checked found to be unworn and then oiled. I cleaned the commutator with 800 grit paper ant it was time to put it all back together.
I reinstalled the field windings using the air wrench after applying loctite to the screw threads. The field post was bolted in the case.( replacing the original rivet) The generator was reassembled and new brushes installed. All done? No I decided to test the generator.
To test I mounted the generator to a board and used an electric motor to spin it. I hooked the field and output connections to the regulator also mounted to the board. I spun it up and checked the voltage. Nothing. Checked the wires scratched my head ah ha no ground. Wood does not make a good return path to the battery. Tried again. NOTHING.
I spent some time looking around the Riley RM forum for generator advice. The one thing I noticed is generators have to spin fast to make power. Well I thought my electric motor spins at 3000 rpm That should be enough. I checked with a handy little digital rpm device and sure enough 3000 rpm on the nose. Checked the generator 700 rpm. The belt was slipping, no noise no smell you learn something new every day. I tightened the belt and got 14 volts at the battery. The generator works. Back to body work.