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Accuspark update
#1
I have been running with an Accuspark distributor on my 1929 fabriscsaloon now for about 2 years and 3,500 miles.
It replaces a Lucas DK4a which is in good condition. I put it together with used parts from several units plus some new and it works well.
However with the Accuspark the engine runs noticeably more smoothly with less vibration on the steering wheel, especially at higher revs. I put this down to reduced timing scatter.
I have now added all the Accuspark's suggested modifications. The coil is 1.5 Ohms which is lower than recommended so I have a 1 Ohm resistor in series with the primary. This reduces the current that the unit has to switch. I have also fitted modern HT leads. These were supplied free of charge with my order for HT leads for my Citroen SM.
Everything is easily reversible to the DK4a or the original DS4 which I also have.
My car has always had a tendency not to fire when cranking with the bacon slicer starter. It seems to drop the voltage too much and the engine often fires at the moment the starter is released when of course the voltage rises.
My battery is getting tired and with the Accuspark it was very reluctant to start on the starter but always 1st time with the starting handle.
I have overcome this by adding a small sealed 6V battery in parallel with the main one. This works fine and both charge without any problems.
There is also a change-over relay that normally connects the +ve terminals of the batteries together. It's wired so that when the starter is activated the relay switches, disconnecting the main battery from the ignition circuit. This leaves just the small battery feeding the ignition while the main battery does the cranking. It works a treat unless the main battery has got so low so that it turns the engine too slowly.
For belt and braces I have connected the normally open terminal of the relay directly to the ignition coil. Thus when the starter is engaged it bypasses the 90 year old ignition switch which I think has some resistance.
Most people probably wouldn't do this but I am pleased with the result and it was an interesting exercise.
Jim
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#2
Hello Jim,
What you did makes sense of course and I'm sure it works fine.
Then I don't much like the idea of paralleled batteries though a small one in parallel with a large one should probably behave well I suppose.
I'm not trying to argue because I find your design elegant but would'nt it have been simpler to replace the tired one?
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