Lumenition is the premium UK brand for electronic-ignition conversions, with a heritage in classic-car ignition systems dating back to the early 1970s. The Lumenition kits use an optical trigger rather than the Hall-effect trigger used by Accuspark and most modern conversion kits, an infrared light beam interrupted by a rotating shutter inside the distributor produces the trigger pulses that signal the coil to fire. The optical-trigger approach has its own advantages and is the basis for the Lumenition reputation for reliability across decades of classic-car use.
Optronic and Magnetronic Ignition Systems
The MGOC Lumenition range covers the two flagship Lumenition ignition product families, the Optronic optical-trigger system and the Magnetronic magnetic-trigger alternative. The Optronic kit replaces the original contact-breaker points with an optical sensor mounted in the distributor, with a fitting kit specific to the Lucas 25D, 45D or other distributor type at the point of order. The Magnetronic system uses a sealed magnetic trigger mounted entirely inside the distributor body. Both systems pair naturally with the Lumenition Mega Spark MS4 high-energy ignition coil, a 3-Ohm coil suitable for use with either the Magnetronic or Optronic non-ballasted ignition systems.
How the Lumenition Optical Trigger Works
The Lumenition kit consists of three principal components. A small base plate fits inside the distributor in place of the original points base plate, carrying an infrared light-emitting diode and a matched photodiode positioned across a small gap. A rotating shutter (typically a metal disc with cutouts matched to the cylinder count) fits onto the distributor shaft in place of the original points cam, interrupting the light beam at the appropriate angular positions. An external amplifier module, a small electronic unit typically mounted in the engine bay alongside the coil, processes the photodiode signal and drives the coil with the appropriate current pulses.
The combination produces accurate, repeatable timing that holds its specification across the working life of the conversion.
Advantages of the Optical Approach
The optical trigger has several advantages over magnetic alternatives. The trigger response is dramatically faster than a Hall-effect sensor, the light beam interruption produces an instantaneous signal change, where the Hall-effect sensor has a small but measurable response time to magnetic field changes. The trigger is unaffected by stray magnetic fields from other engine components, the magnetic-trigger systems can occasionally be affected by magnetised distributor shafts or by nearby magnetic components, while the optical trigger is immune to such interference. The trigger remains accurate as the components age, the optical components do not drift over time in the way that magnetic-trigger systems can.
For owners who want the most accurate ignition trigger available, the Lumenition optical system is typically the appropriate choice.
Installation and Application Coverage
Lumenition installation involves fitting the base plate inside the distributor (in place of the points), fitting the shutter to the distributor shaft (in place of the points cam), routing the wiring from the base plate to the external amplifier module, and connecting the amplifier output to the coil. The amplifier module is typically mounted in a cool location in the engine bay, away from direct heat sources, with appropriate mounting hardware supplied in the kit. The wiring is more involved than the Accuspark conversion because of the external amplifier, but the wiring diagram supplied with the kit makes the installation straightforward for any owner with basic electrical competence. Lumenition kits are stocked in the application-specific configurations for the principal Lucas distributors used across classic-MG production.
The technical team is available to advise on the right specification for a specific car.