distributor installation

I am having trouble trying to locate the distributor so that the rotor arm turns properly.

From what I can tell, I have to:

1. Insert the coupling (549611) and place that correctly with its offset teeth sitting nicely in the driver below.
2. Insert the distributor so that the dog on the end with its offset teeth sit correctly in the coupling.
3. Position/turn the distributor so that (hopefully) we have approximately the right timing.
4. Tighten up the bolt on the bracket and the adjusting bolt.

When I install it as above, it initially feels about right. Initially, the rotor might feel OK but it then loses it, and either doesn’t rotate, or rotates unevenly or doesn’t rotate at all. And at that point, I can turn it manually i.e. it is obviously not sitting correctly.
It almost feels like it is not quite long enough and only a mm or two of the teeth are engaged (sorry to be so vague).

I did wonder if the locking bracket could go the other way up – but I don’t think that is the issue.

I did wonder if the locking bracket could go higher up the distributor shaft: but that doesn’t look possible.

I did wonder if I am missing any part e.g. the coupling just seems to sit on top of the lower parts of the distributor driver and maybe there is something that holds it in place..

Any ideas what I have done wrong?

p.s. you can see a thin spring on the tail of the distributor, and i can't understand what its purpose is

Long time ago but I thought u had to put the engine onto cylinder 1 TDC before installing the distributor

Apologises if that’s wrong

Also found this which I hope is useful

For a Lucas distributor, yes, #1 on the cap should roughly point to #1 plug

kermit_rr said:

For a Lucas distributor, yes, #1 on the cap should roughly point to #1 plug

Click to expand...

Bless u for confirming that as wasn’t 100% sure with it being so long ago

I have a ducellier on mine, think it's 90° out.. doesn't matter until you put the plug leads on in the wrong order and get a good backfire

Thin coil spring at the bottom of pic retains pin keeping adaptor on [ different ones for different vehicle]
Is this the original unit?

tottot said:

Thin coil spring at the bottom of pic retains pin keeping adaptor on [ different ones for different vehicle]
Is this the original unit?

Click to expand...

I don't know if this is the original distributor from when the car was made. The carb has been replaced with a Weber (which I know was a common change).
I know that tdc etc is relevant for setting the timing (I have a strobe light to help) but I don't think the position has an impact on my issue, which I need to sort before I concentrate on the timing

But it is the distributor that has been in the car for the last few years.

Not familier with the Duceilier distributor, the ones I delt with were the Lucas but late series 3 had the Duceilier.

Get an electronic Lucas 45D4 , Duc dizzies are very robust but not a patch on the Lucas

The improvement is vast ...

How much end float is there on the shaft?