Fitting a Lucas E3L dynamo to a model C Rapide

54crapide

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VOC Member
I am trying to fit a Lucas E3L dynamo to a model C Rapide. The dynamo is a model 20037 E3L with a parallel end on the armature and PD33 adapter. My problem is that the dynamo does not mate to the back of the chaincase correctly. First the bearing retainer plate on the dynamo gets in the way. Even with that removed and with the face of the dynamo flush with the back of the chaincase, the end of the armature does not protrude far enough into the chaincase to allow the internal drive parts to be fitted.

I believed that the D models were fitted with Lucas generators standard and have tried to get the same model/configuation hoping that it would fit my C without modification. I can modify the Lucas that I have and make it work but don't understand why that is necessary.

Will a Lucas dynamo as used on a D fit a C without modification?

Is the dynamo that I have the wrong one? If so what do I need?

lucas front.jpg
LUCAS E3L DRIVE END

lucas and miller.jpg
LUCAS MILLER COMPARISON (lucas on right)

LucasToSeriesD.jpg
PARTS DIAGRAM

lucas parts.jpg
THE PARTS I HAVE

lucas protrusion.jpg
NOT PROTRUDING ENOUGH
 
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piggywig

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Non-VOC Member
54crapide,

All that did not really answer your question if the E3L in question has been adapted from a different Brit. bike! Mine was originally on a B.S.A. and like yours the shaft was only long enough to take one thread to hold the sprocket in place. A spigot nut was made that fitted inside the sprocket along with PD16---PD17a/s and a purpose made PD23 tab washer. And even then a suitable thickness washer may be needed to get the sprocket to mesh correctly. As you have found, there may not be an easy answer but it can be done with a little effort, although with so little room to work the assembly takes a while to line up while the nut goes on, (especially if it drops into the chain-case!) I am not keen on removing mine to have a quick check but I believe it is as I have written. It has functioned well since the seventies with the occasional generator rebuild and conversion to 12 volts. In hindsight it would have better by far to have used the correct generator in the first place!
Col.
 

ogrilp400

Well Known and Active Forum User
Non-VOC Member
I made my own adapter to bring the sprocket in line with the center run of the chain. If your adapter doesn't align then you will have to do the same.
 

54crapide

Forum User
VOC Member
Thanks for your information.

I agree that it would be best to use the correct generator and that is what I am trying to achieve. I thought that a Lucas as fitted to the D models would fit a C without modification. Perhaps this is not true or perhaps I have the wrong generator?

Here is a picture of what I have -

lucas front.jpg
 

craig

Well Known and Active Forum User
VOC Member
dont you need the D series parts to adapt this Lucas E3L?
I am just guessing, but it looks practical.
PR24/2 is listed as Lucas E3L

LucasToSeriesD.jpg
 
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piggywig

Well Known and Active Forum User
Non-VOC Member
Compared with my E3L your shaft is obviously problematic at the drive end, in that it is so short and without an extended male threaded end. As they were fitted to such a large range of bikes apparently the armatures must have been many and varied. I wouldn't say it cannot be adapted but you might need to call in a favour from a mate who is handy with a lathe! Happy Christmas.
 
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