That's my opinion, with the 123 ignitions your paying 100's of pounds for what is basically a shiny stock dizzy with a switchable petronix/accuspark module...
I have to admit I am not up to speed on all the technicalities. However, one of my main reasons for giving the 123 a go following on from Jim Calvert's comments (I should say Jim didn't pass an opinion on the 123 himself but said Dan at vintage speed swore by them), was that it wasn't a stock mechanism.
MAINTENANCE FREE TIMING
In a 123ignition, all moving parts – like the original points, the centrifugal weights, the springs, the bearings and the vacuum-diaphragm – have been replaced with just one moving part: the central shaft with the rotor. The internal electronics provide the right advance and the optimum dwell-angle throughout the rev. range to maintain peak energy and peak performance. There is no wear altering the timing of the 123ignition: once set, you’ll never have to worry about it again!
SIXTEEN ADVANCE CURVES
With a little switch – see picture – behind an opening in the bottom-face of the billet-housing, you can select the best advance-curve for your engine. Why? Well simply because many different advance-curves were prescribed by car-manufacturers. You buy one 123ignition, but you get sixteen different distributors!
SPARK BALANCING
Spark Balancing is an advanced technology normally used in Formula 1, where engine speeds are tremendously high. This technique is built into the 123ignition. Its microprocessor constantly monitors the amount of energy contributed by each individual cylinder. Assume for example that the compression of one cylinder differs from the others. The motion of the flywheel would be less smooth, and so is the motion of the camshaft. The 123ignition detects this, and adjusts the timing of each cylinder individually. This results in a much quieter engine, more power and less wear.
AUTOMATIC DWELL CONTROL
A mechanical distributor has a fixed dwell-angle, sometimes resulting in overheated coils at low speeds, weaker sparks and misfiring at high speeds. Why? An ignition coil only needs a couple of milliseconds to charge, but with a fixed dwell-angle these are ”overcharged” many times when idling, resulting in… overheated coils! At high speeds the fixed dwell angle tends to leave too little time to fully charge the coil, resulting in… weaker sparks and misfiring! The 123ignition measures the amount of current flowing into the coil, in such a way that the strongest possible spark is guaranteed at all engine-speeds, whilst keeping the coil cool. Also to prevent coil overheating, the power to the coil is cut-off as soon as the engine stops.
A summary of all the advantages of the 123 ignition:
16 user selectable electronic advance curves,
Smooth engine torque curve,
Attractive ”original” look,
Less emissions,
Better starting,
Maintenance-free,
Simple installation,
Variable dwell-angle,
Better fuel consumption,
Stronger spark at all speeds,
Easy timing: with built-in LED, and
Spark balancing: less noise & more power.
I know that there is a large dosage of sales speel in this, but for me the change from the springs/weight/balences was the main factor given my experience with the other SVDA's I have tried. To date I haven't regretted the change ... fingers crossed.
