Electronic ignition

[John Cornforth]

Five years ago I looked around for an electronic ignition for my 6 volt Pearl, but couldn't find anything suitable.  I ended up making my own, which is of the simplest 1960's type, categorised as "Transistor assisted contacts" and needs only two transistors and a handful of passive components.

The standard (good condition) DK4A with its points and condenser are retained, but the points current is reduced to 50 mA, so contact wear is negligible and the stress on the condenser is eliminated.  It took some time to select a switching transistor with a low enough voltage drop when on, as a 6 volt system has little margin.  I settled for an IGBT which drops less than a volt.  Whilst this reduces coil current a little compared to a new set of points, the very rapid switching more than makes up for this.  One gets a good spark even with slow cranking speeds, and starting (even with "old" petrol) and idling is noticeably better.  One of my aims was to avoid occasional misfires which can lead to fouled plugs, and this has been successful.

The unit is mounted low down in the engine bay in a small black metal box with period looking terminals.  I took care with the construction to use generously rated components, mounted on tagstrips and with the larger items araldited to the inside of the box  to avoid vibration.  The other precaution was to use suppressed spark plug connectors, as there was a small risk that the high level of electrical noise in a unsuppressed Seven engine could upset nearby electronics.

In principle the original ignition setup can be restored at the roadside by swapping over a few wires, however in 5 years usage it has proved completely reliable.


As a general observation, my experience of consumer grade electronics from the far east is that there is often no testing of any description, as this would push up the cost too much.  Instead, the manufacturer's philosophy is to offer a replacement for anything which fails.  For a clock radio or a kitchen timer this is merely annnoying, but for something you are going to rely on it's unacceptable.  The only thing I can suggest is to try and give items of this nature several hours of soak test before fitting, because failures tend to be in the early stages.

[Oxford Jack]

Just for balance I will add a note from the other side of the story.
I bought and fitted one of the new Accuspark dizzy's in May 2017. It ran with all the benefits noted by previous correspondents and I was entirley happy with it in the 700 plus miles I covered on a newly rebuilt engine before starting the Euro Tour. On the day we left for Dover I had covered all of 3 miles when the engine cut, I was able to restart sufficiently long enough to crawl into a bus layby, from the main road through Woodstock, Oxon. A few minutes diagnosis indicated no spark and since the coil was fine and electricity was reaching the dizzy, I swapped it for the clockwork backup it had replaced.
I returned home, borrowed a second clockwork item from my other seven and completed 3000 miles through Europe without further incident. I returned the faulty item to Accuspark, which got lost in the post (note even 2nd class Post Office parcels have a tracking number on them, which enabled me to claim its loss from Accuspark) I have since fitted the new Accuspark dizzy and immediately noticed the improvement in running, tractability and tick over. I have also bought a second one for the other seven.
I always carry a second dizzy under the back seat, complete and ready to fit. On longer adventures I wil now borrow the second electronic item as a spare, otherwise its a clockwork spare for all other journeys. So you could say a convert and convinced by the improvements over the possible failure, which of course has been previously noted in this thread, with the current supply of clockwork dizzy components.
Hope this helps
Regards Jack

[Charles Levien]

Having just purchased a 38 Ruby I am thinking of changing to electronic ignition.There is nothing wrong with the original Dizzy and it starts ok,I intend to use the car on a regular basis for fun and want to cut down the possible problem areas.I admire 'purists' and their desire to keep things as is.Iam interested in sensible comments/pitfalls on the subject----any takers? Cheers.

Look at (google) “Electronic Ignition — DK4A distributor, Doug Castle”

Charles, in bl- - dy cold Norfolk

[David Cochrane]

I bought an Accuspark unit and fitted it to the RP. The engine seemed to run well with it, although I didn't notice all that much improvement; I think the main benefit was the automatic ignition advance & retard. Yesterday the car was very reluctant to start and wouldn't run properly. After spending most of the morning faffing about, we changed the distributor for the old one, not because we really thought that it could be faulty (it's a brand-new unit, innit?) but because we were running out of ideas. Instant result!

I contacted Accuspark and tried to persuade them to send me another unit so that we could go away with the car on a long-planned weekend, but they refused - they insisted on having the old unit back first. It apparently isn't "company policy" to do their best for their customers. I must say that I am not impressed with this distributor: it has run for less than 2 hours, there is already nearly 1/16" play in the spindle and it has failed.

There seems to be a disturbing trend towards unnecessary replacement of tried & tested electrics with modern electronic gismos, such as the alternator and this distributor. Some modern developments are great (LEDs for instance), but I wonder about some others.

[Charles P]

There seems to be a disturbing trend towards unnecessary replacement of tried & tested electrics with modern electronic gismos, such as the alternator and this distributor. Some modern developments are great (LEDs for instance), but I wonder about some others.

Well said David.
I'm waiting for someone to dispense with the awkward updraught Zenith with injection and proclaim that "it's so much more driveable like that."

Charles

[Alan]

Don’t tempt me! Back in the 1960s you could buy a bolt on “fuel injection” unit for your motorcycle. If I looked, I’ve probably still got one.

[Ruairidh Dunford]

Similar appear to still exist Alan - somebody will have looked into (or done) it.

[Alastair]

I've just noticed David's comments about play in the spindle on his Accuspark unit. I posted previously on another thread about electronic distributors concerning a similar problem with then first one I bought - the crimping which attached the cam to the spindle had failed allowing the unit to retard i8tself when running. Accuspark replaced it and I've had no problems since.
However, a friend had a similar fault with his new one from Powerspark, which again was replaced and is now running fine, so there would appear to be a weakness here. Has anyone else had similar problems?
I would still recommend them, but like Ruairidh, I always carry the original just in case...
Alastair

[Stuart Giles]

Don’t tempt me! Back in the 1960s you could buy a bolt on “fuel injection” unit for your motorcycle. If I looked, I’ve probably still got one.

Alan,
     was it one of these?



A mate had one fitted to his AJS 500 when I was at college, we used to tease him that it would be just as effective to rig his twistgrip to a bath tap which was pointed down the inlet port.

[Mixer]

Hi all,
For the record I fitted my electronic ignition to my Ruby and it starts even better than before,seems perkier as well.
Thanks for all the positive comments,I feel I made the right decision.Only time will tell if the consumption improves but either way I would certainly recommend it to others.