From Citroen SM Wiki


I initiated, paid for the development and had project control of the Lumenition system. It was done under contract for my original company, Hypertronics Ltd. Lumenition was the 'big survivour' in aftermarket electronic ignition kits in Europe, and supplies both racing professionals and NATO forces.

The requirements were- Full contactless electronic ignition.

No modification to car. Easy to install.

These all remain true. Citroen had long since abandoned the early bakelite four paddle rotor, so the later 3 paddle modern plastic unit was standardised on. A kit was designed, and comes complete with all parts needed to install, including a chassis earth wire, as the wing on an SM is not always well earthed.

-- (Transcribed from a Sport-Maserati-L post from) Andrew Brodie


  • If you have a working set of contact breakers properly set, with the timing perfect, the Lumenition unit will simply 'drop in' and the ignition timing will be easily accurate enough to start and run the car, though of course it must be checked and reset precisely as soon as possible. It was designed this way deliberately.
  • Thus, if you tune up your car correctly, you can fit the Lumenition, and place the original breakers, breaker wires and condensers in a bag with a small screwdriver in the boot(trunk) for instant reversion in the unlikely event of failure. The distributor should be well greased while installing, particularly on injection cars and those that are not used very regularly.
  • The Lumenition is bench tested and synchronised to less than 1 degree at the flywheel. It provides a superior spark using the standard coil. The rev counter works correctly. Apart from a timing re-check at say 100 miles to confirm installation and a visual check at major services for standard distributor problems having developed and the lenses being reasonably clean (it is actually VERY resistant to dirty lenses) it is maintenance free.
  • The Lumenition system will 'cover up' faults in the distributor such as incorrect centrifugal advance but to work properly it expects the distributor to be in full working order. This is not at all difficult to achieve if yours is worn, it is simple enough to repair in most cases.
  • You can use the Lumenition system with coils that do not have an external resistor. They must be 'traditional' coils, not 'sports' coils. The point being that they must NOT be very low resistance. 'Sports' coils attempt a larger spark by requiring a higher contact breaker current and trade reduced contact life for bigger spark. The Lumenition has the reserve to switch standard coils but is not guaranteed safe on 'sports' items.

They do sell a 'performance' upgrade if you feel it will be worth the price!

Problem Areas

(All minor)

  • Very very early distributors are shallower than all the rest, and to fit the Lumenition 'cassette' about 1/8" needs to be removed from the lower end of the cassette. This is done neatly by sawing it flat immediately below the lower locating peg, removing the angled peg shoulders.
  • If I had come from a hot country I would have decided on a different installation position to the top of the LH wing. I therefore now recommend fitting further rearwards and lower closer to the LHM tank. A simple aluminum bracket/carrier can be made up to locate the modules. I originally reasoned that the wheel air turbulence would cool the units at all times when moving. But of course the real problem is in stationary traffic!
  • Rarely the 3-wire plug/plug contacts cause difficulty by going open/high resistance.
    • Prevent this by mating/demating them a couple of times then grease and mate.
    • I tried to get Lumenition to replace the contacts with Gold ones but they never did, probably because any improvement would be marginal over the existing Rhodium.
  • The Lumenition units do not switch below about 8V. You must therefore ensure that your wiring is clean and that the supply to the system is good. Poor wiring can lead to bad hot starting with the system.
  • When switched on and off the Lumenition delivers a full spark, just as does a standard contact breaker system. This is ONLY a problem if you have other defects that inhibit imediate starting.
    • Due to the much better spark this can lead to involuntary (!!) demounting of the injection manifolds on that one day of the year when the cold start injector puts just exactly the right amount of fuel on the 'surface evaporation' plate.
    • (My Citroen DS23 IE used to do this TWICE a year on STANDARD breakers!!).
    • both DS injection and SM injection are prone to this problem:
      • the injection plenum or plenums are mounted, on one side, to the injection headers by rubber tubes. A small lip inside the tubes separates the tubes of the plenum from the injection header by 2 or 3 mm.
      • the plenum is mounted, on its other side by rubber mount(s).
      • the plenum is thus isolated electrically from the engine
      • Spark plug leads in poor condition can leak current to the plenum. When the cold start injector operates, the plenum contains fuel vapour. If current leaks from the ignition to the plenum, a spark may jump internally from one plenum tube to the corresponding injection header....
      • Explosions in the plenum can be averted by attaching a wire (lighting flex gauge should be sufficient) from some point on the plenum to some point on the engine.