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end of dynamo. what is missing
1934 Ruby.


What seals off this end of the dynamo please? This is the end of the dynamo shaft at the distributor end. Looks like it might be held in by a circlip, but whatever it is, mine is missing.
You should have an end cap ( a bit like a coreplug to look at) secured by a circlip.
Maybe just the ramblings of an old coot, but I seem to recall reading that this cover is the same size as one of the A7 block core plugs, or was it perhaps the oil pump cover disc?

The circlip is simply a ring of springy wire with a short inward 'leg' so you can grip it with pliers, so could fairly readily be improvised.
It strikes me your nut is a long way out and is probably why there is no endcap, because it wont fit as the nut is in the way. Id say something wasn't quite right with your dynamo
Yes the end cap is the same size as a core plug and is held in place with a wire clip. The nut looks to be proud because the worm gear for the dizzy is not located correctly on the shaft. It should be located on a key which is in a key way on the shaft. It looks to me that it not lined up with the key so therefore It will not go far enough down the shaft. Also under the nut between nut and gear should be a spring washer.

John Mason.
Would you believe it "Her who must be obeyed" refers to my Ruby as the toy.

Must be the big core plug at the end then John I reckon?

Yes re the nut, it's not on proper. And there probably ought to be some evidence of grease around there (sorry Andrew, we're just trying to help).
Thanks everyone, all help appreciated. It is a dynamo I have just assembled, everything seems to be back together properly with the gear properly on the shaft on the woodruff key. I struggled to find a nut the correct thread and the one fitted is rather 'thick'. The intention is to apply grease before fitting the end cap, but in the pile of bits from two dismantled dynamos I cannot find an end cap -- hence the question.

Ah, no spring washer. Considered wisdom on various engineering websites conclude that spring washers do not work and any washer tends to helps things to come undone. [Only registered and activated users can see the links Click here to register]

Now that I know what it should be, I'll see if I can make a deeper welch plug, domed enough to go over this nut.
The nut is a 3/8bsf thinner than a std nut with a flat spring washer. Terry.
If you can't get a correct nut, why don't you just cut this overly deep nut down to size? That way you can fit the blank disc cover without any modification!
Yes, I'd pop the nut in a vice and 'relieve' the non-contact face with a file or angle grinder. As always when butchering nuts do it on a bolt so you can easily re-start the thread.

You are quite right about spring washers Andrew, though in an application like this they aren't likely to do much harm. If concerned about loosening you might consider a split pin or spot of mild loctite (just be certain you can undo it again).

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