DK4A distributor service replacements

[JonE]

I came across an old Barry Riseley post on distributors, where he referred to the 

"Service replacement distributors were lablelled either Service No's 400206 or 40224/S. (and I think the different numbers simply reflect a change in the Lucas numbering system, rather than a change in Distributor characteristics).It is interesting to note that these later types were also specified for a range of other Austin cars of the 1930's (were supplied without clamp plate and drive gear)"


I have found a 40224 A which I think may be same but from an Austin 8 or 10 - manufactured 1951. No drive gear or drilling. Does anyone know what the difference in characteristics are? It looks absolutely identical but I haven't started to strip it yet.

[Chris KC]

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Looking at the specs here (below) I would venture that the /S was a vacuum advance unit (those 2 additional part numbers are for vac advance unit & bracket) - otherwise identical. An 'A' suffix usually stands for 'auto advance'.

The 40224 or 40224/S was specified as a service replacement for a number of different parts of similar specification, most likely they differ in drive gear fitting details but highly likely they can be made to fit a Seven.


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[JonE]

very interesting Chris - so perhaps Barry's 2006 post was a little bit wrong. The chap on ebay had misread the code (or at least completely misquoted it) but fortunately the picture on the side of the unit revealed.

The 7-8.5 degrees is presumably a wider catch-all, or a more rigorous appraisal of their action, 15 years further on...

Any advice on drilling for end gear? I was thinking it would be possible using an old gear as a guide, but is an easy enough job or an engineers one?

[Chris KC]

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I would personally not attempt it without a vee block and a decent bench drill and a nice sharp drill bit, but I happen to have those things! There's quite a high risk of not going through quite straight.

[JonE]

Brilliant - I shall make a V block and buy a new bit - I've got the pillar drill.
thankyou.