electronic distributors - any further feedback?

[Colin Reed]

Colin, a bench test comparison will not tell you how one distributor will perform against another on a car, however do I agree it is useful for diagnostics if you have a known set of parameters to compare against.

Of cause it will it will replicate as if it is on the Engine

[Ian Williams]

No Colin, I don't think you understand, that will not tell you how it actually reforms, only what degree of timing scatter, advance curve and point bounce a unit exhibits. If you are comparing two distributors neither of which have and ideal advance curve what will that tell you, that one is different to the other? Unless of course you know before hand what the ideal parameters are, which is exactly what I have been trying to say. With a seven we do not have that information unless we do extensive testing under measured conditions on an engine, this is where a rolling road comes in, or measured runs under controlled conditions, as I am sure you know if you actually stop and think about it for a moment.

[Charles Levien]

No Colin, I don't think you understand, that will not tell you how it actually reforms, only what degree of timing scatter, advance curve and point bounce a unit exhibits. If you are comparing two distributors neither of which have and ideal advance curve what will that tell you, that one is different to the other? Unless of course you know before hand what the ideal parameters are, which is exactly what I have been trying to say. With a seven we do not have that information unless we do extensive testing under measured conditions on an engine, this is where a rolling road comes in, or measured runs under controlled conditions, as I am sure you know if you actually stop and think about it for a moment.

As mentioned in an earlier post I have a modern distributor ( Mini) with the advance and retard weights welded together — on electronic ignition. So any curve is independent of bob weights. The car goes very well with this set up with good torque at low revs ( Jack French road cam) and good performance up to 5000 rpm.
Mine is a road car and I should like to know if anyone else is running a car successfully with this set up.

Charles

[JonE]

Charles - what is the exact distributor spec? If modern, does that mean it has a vacuum advance disabled or enabled?

[Charles Levien]

Charles - what is the exact distributor spec? If modern, does that mean it has a vacuum advance disabled or enabled?

Vac advance disabled ie locked in position by a small spring. I’m away from home and can’t remember exact spec.

Charles

[Tony Press]

Charles - what is the exact distributor spec? If modern, does that mean it has a vacuum advance disabled or enabled?

Vac advance disabled ie locked in position by a small spring. I’m away from home and can’t remember exact spec.

Charles

Getting back to the original discussion- perhaps I am miss-reading it but-

A search for the electronic DK4a unit gives -

Powerspark DK4a at £100

https://simonbbc.com/Powerspark-lucas-dk...stributor/

Accuspark at DK4a £130

http://www.accuspark.co.uk/dkdistributor.html

Both look very similar. Powerspark claims that they arranged to have the copy produced.

All pictures seem to show the red rotor.

[Tony Press]

Charles - what is the exact distributor spec? If modern, does that mean it has a vacuum advance disabled or enabled?

Vac advance disabled ie locked in position by a small spring. I’m away from home and can’t remember exact spec.

Charles

I see that an 'aged' electronic distributor is fitted with 'acorns' on what appears to be a push in cap. Do the caps have threads? 

And the Accuspark page notes that carbon cored rather than copper cored leads must be used. 

Another website notes -

"Solid metal (copper, tin-plated copper and/or stainless steel) conductor wires are still used in racing on carbureted engines, but can cause all sorts of running problems if used on vehicles with electronic ignition, fuel injection and engine management systems, particularly if vehicle is driven on the street — and damage to some original equipment and aftermarket electronic ignition and engine management systems can occur. Solid metal conductor wires cannot be suppressed to overcome EMI or RFI without the addition of current-reducing resistors at both ends of wires."

I suspect there is no need to worry about the engine management system on a Seven (not yet anyway)

Anyone using copper cored leads ?

[Ruairidh Dunford]

Tony,

I run all the units I have using copper cored leads, without issue. I have a set of the carbon leads but have never fitted them.

I only have experience of the Accuspark product but Forum user Tod has the Powerspark unit, which looks identical, and is very happy with it. As an aside, the comparative pricing structure of the products appears to have reversed recently.

[Charles Levien]

Charles - what is the exact distributor spec? If modern, does that mean it has a vacuum advance disabled or enabled?

Vac advance disabled ie locked in position by a small spring. I’m away from home and can’t remember exact spec.

Charles

Jon, if memory serves me right I think it’s a 25d

Charles

[JonE]

Jon, if memory serves me right I think it’s a 25d

Thanks Charles. I think on balance I'd (fussily) not want a vacuum thing showing.. but (thinks...) I wonder whether there was a precursor to it without? I imagine not, otherwise they would be well known! Good to know though.