DK4A Rotor Arm & Drive Gear Queries

[John P]

Hi,

I removed the distributor cap yesterday and noticed that the Rotor Arm was very loose on the spindle, in fact you could rock it from side to side through a noticeable angle.  (This was a lateral rock not rotational).

Worried this might allow the rotor to damage the contacts in the cap I very crudely jammed a small piece of polythene between the bore of the rotor and the spindle which took out all the movement but obviously I need to get a new rotor.   I'm also a bit concerned how this happened as it was a rotor I fitted around 1,000 miles ago.

Anyway, there seem to be two types of rotor available, one black as supplied by Seven Workshop and one Red from Distributor Doctor which is claimed to be better although slightly more expensive.   I need to order a few small bits from Seven Workshop anyway so using theirs would also save me some carriage but is the Red type actually better?

Also I'm considering replacing the distributor drive gear as a mine is very worn but I like the fact that's it's made of Bronze which seems like a good idea in the application.   I've also seen comments that the new ones from Distributor Doctor don't always last very long as they are apparently made from un-heat treated steel but has anyone experienced any issues with these.

Finally, I assume the gears supplied by Seven Workshop are the same as the Distributor Doctor ones as both are exactly the same price.

Any advice would be appreciated,
John.

[Ruairidh Dunford]

Finally, I assume the gears supplied by Seven Workshop are the same as the Distributor Doctor ones as both are exactly the same price.

That is not correct, they are not the same, I use the ones from the Seven Workshop.

[dickie65]

I have used electrical tape or silicone sealant to help with this problem as a tempory repair ( 5 years worth of tempory ) I also have had a rotor break in half whilst doing 45 mph taped it up with leccy tape and drove home I had a spare in the car but the leccy tape was in the glove box so instant fix.

[Peter Naulls]

Also worth noting that the distributor caps from the Distributor Doctor are a different size too, presumably to match their own base plates.

[Bob Culver]

On other cars loose rotors have worried me. Just fit over a piece of paper.

[David.H]

For what it is worth I have had Remax bases & caps that did not take kindly to Lucas ones and vice versa . CI caps also could be tight fits! There are a lot of DK4A type ex military distributors around and some (identifiable by the body base being machined to a simple sharp right angle rather than curved like Lucas) and these may not like non Lucas caps. I believe they may have been originally for Centurion tank generator engines, but that was based on a Morris 8 unit.....which may have a different direction of rotation.A lot of maybes I'm sorry!

[Jamie]

My distributor gear which came from the Distributor Doctor was not hardened. I case hardened it before fitting it.

Jamie.