DEL dynamo distributor location

[Howard Wright]

Hi All

I have a DEL dynamo on both the RK and the Special.  In both cases the distributor is held in place simply by a spring and bolt through the clamp plate. This plate must rotate to provide the advance retard mechanism. On later dynamos the distributor is held by a set screw through the the side of the end frame into a slot around the distributor body.

On the Special I have noted that the distributor appears almost loose and vibrates as the clamp plate isn’t held down well enough by the spring. Even with a quite strong spring there is quite a bit of movement. Fortunately it doesn’t appear to affect the ignition timing.

Has anyone drilled and tapped for a locating set screw on the end frame of a DEL?  If so can anyone give me the exact dimensions for the hole? I’m using a DJ4 distributor which has the slot around the body.

Cheers

Howard

[Chris Garner]

I have several DEL dynamos. On some, where the distributor is fitted, the hole has a bronze / brass bush fitted. I've never understood whether this is ex works - ie two different models? Regardless, the distributor should be a good fit in the hole and so should negate the need for a side clamping screw.

[JonE]

I've got a brass/bronze bush too. Alloy end casting.

[Howard Wright]

Hi Both

Thanks for the replies.

I have a dynamo with an end frame that is / has been bushed which I could use. However the one on the car (without the bush) has been modified to take a rev counter drive.  I don’t feel like butchering another end frame.

I may try removing the spring on the clamp holding bolt and fitting a bolt that is tightened to an interference fit on the clamp.

Cheers

Howard

[Tony Griffiths]

I may try removing the spring on the clamp holding bolt and fitting a bolt that is tightened to an interference fit on the clamp.
Cheers, Howard

That's what I did. I used a post-assembly "wicking" grade Loctite on the screw and gently tightened it down until the distribute could move easily - yet with no up-and-down play. When the Loctite sets it's sufficient to hold the bolt in place yet can be undone easily. I found that the underside of the clamp was not as flat as it might have been and used a little draw filing to improve things. Years ago, for competitions, I used to bolt the distributor down at full advance; I swore that it made a difference....probably in my head.

[Howard Wright]

I may try removing the spring on the clamp holding bolt and fitting a bolt that is tightened to an interference fit on the clamp.
Cheers, Howard

That's what I did. I used a post-assembly "wicking" grade Loctite on the screw and gently tightened it down until the distribute could move easily - yet with no up-and-down play. When the Loctite sets it's sufficient to hold the bolt in place yet can be undone easily. I found that the underside of the clamp was not as flat as it might have been and used a little draw filing to improve things. Years ago, for competitions, I used to bolt the distributor down at full advance; I swore that it made a difference....probably in my head.

Thanks Tony

[Dave Mann]

I have come across a badly worn Lucas dynamo end casting so badly worn the distributor flopped around.

[Howard Wright]

Hi All

For completeness, an hour in the workshop and I did this....

I silver soldered a washer under the locking nut, threaded a bolt up from underneath and using a lock nut I can adjust the plate to just slide smoothly when moving the advance retard lever.

One reason for the wobbly distributor was the fact that the top of the end plate (brass bushing) was at a different height to the bracket on to which the adjusting plate is screwed  . A washer under the plate cured this.

The modifications have made the tickover much sweeter so I guess the loose clamp must have been affecting the timing.

Thanks for comments and help.

Cheers

Howard