The 123 Ignition System is a complete replacement distributor for classic British cars, incorporating a sophisticated solid-state microprocessor housed within a polished aluminium body, configurable by the owner so that the advance curve matches the specific engine rather than being preset by the manufacturer. The 123ignition distributor replaces the original Lucas unit in the engine, with the timing curve set through a computer interface or through onboard adjustment to any specification the owner requires. For tuned, modified or non-standard engines where the original Lucas advance curve is not the right specification, the 123ignition is typically the appropriate choice.
How the 123ignition Works
The 123ignition distributor uses an electronic-trigger arrangement similar to the CSI Magnetronic but with the advance curve programmed by the owner rather than preset by the manufacturer. The shaft rotates in the engine in the conventional manner; a Hall-effect sensor detects the shaft position; and the internal control circuit calculates when to trigger the coil based on the programmed curve. The curve specification can be set through a small switch arrangement on the body of the distributor (for the simpler variants), or through a USB or Bluetooth interface to a computer or smartphone (for the advanced variants), allowing precise control of every aspect of the curve, initial advance, maximum advance, the rate at which the curve climbs through the rev range, and the vacuum-advance characteristic (for variants that incorporate vacuum advance).
What Programmable Curves Provide
A programmable curve is valuable for any engine running on a specification different from the original. A Stage II head with a hot camshaft typically benefits from a faster advance ramp, more advance coming in earlier in the rev range to match the engine's revised breathing characteristic. A modified compression ratio (whether higher or lower than standard) typically needs an adjusted maximum-advance setting to match the revised combustion conditions. A car running on modern unleaded petrol with octane booster typically benefits from slightly different advance than a car running on premium unleaded without additive.
Each of these specifications can be programmed precisely into the 123ignition's curve, optimising the engine's behaviour for its specific configuration. For a standard-specification engine, the 123ignition can be programmed to the original Lucas curve, with the option to refine the curve later as the owner experiments with different settings.
Installation and Application Notes
123ignition installation is similar to the CSI installation, removal of the original distributor, fitting of the 123ignition unit in its place, connection of the wiring to the coil, fitting of the appropriate cap and rotor arm (typically supplied as part of the kit), and setting of the initial timing. The curve programming is done either before installation (configuring the unit through the computer interface) or after installation (setting the curve through the on-distributor controls or through a connection to a portable computer). Either approach is straightforward, and the curve can be adjusted at any later date as the owner refines the setup. The 123ignition is stocked in the application-specific configurations for the principal classic-MG engines, the four-cylinder B-Series, the four-cylinder A-Series, the six-cylinder C-Series and the V8 Rover.
The technical team is available to advise on the right specification for a specific car and intended use.