Distributor

[Tiger]

Hi people
Any one know a source for DK 4A distributor advance springs.
Tim

[Chris KC]

http://www.distributordoctor.com/

Mind you they're fifteen quid a pair...

Spring set number is 405396/S.

Before making this investment I'd advise to make sure the various posts and toggles are all fairly tight as they work loose and then a new pair of springs is not going to help you.

[JonE]

Yup. check the posts on the bottom of the cam which fit in the toggles first. I found they were more important that wear in the toggles... and perhaps the springs.
If anyone has any good ideas for how to build up worn metal cam toggle-posts...

[Tiger]

Thanks.
After the comments wondering why Extra strong springs are fitted.
Maybe these are hiding worn parts.
On the cam toggle posts
Can new posts be fitted ?
Not had a good look yet

[Chris KC]

A lot of parts have been chopped & changed over the years, the DK4A was widely used and had numerous variants for different applications. Also I've known more than one person advocate simply locking the weights up and setting with some advance.

As for loose bits,  the best advice I can give you is look out for a less worn unit. The ones with welded posts seem to fare better. Otherwise the 'Distributor Doctor' appears to have cornered the market here. He can at least supply most of what you would need.

[JonE]

But presumably not these! Can anyone fix?

[Chris KC]

Jon I think the only real answer there is to drill them out and weld in new posts cut from steel bar/ wire; this of course requires some precision
You may be better off just looking for a better one.

[Ian Williams]

I make new ones from silver steel Jon, silver solder them in which hardens them at the same time.

[JonE]

so can I get that in rod form to suit? That starts to sound do-able...

[Ian Williams]

You can purchase silver steel from model engineering suppliers amongst others. You need access to a lathe to turn a shoulder on the new pin or make slightly oversize pins, I have on occasion bored the the holes in toggles back to round and square, then made new pins to suit. Of course you can braze/ silver solder up the worn holes and then bore them back to size, you can also sleeve the bore of the cam to remove wear on the spindle. As Chris said accuracy is important for a good function, particularly with points, unless of course you use electronic which can accomodate all sorts of vagaries in the mechanism as we have seen with the Accuspark units which have more slop new than many worn Lucas units.