Mercedes R107 — Points vs. Electronic Ignition

While I am perhaps overly indebted to authenticity, there comes a point when modification is just worth it. Prime example, points ignition vs. electronic ignition. 

Admittedly, I was very skeptical when I first installed electronic ignition in my 1965 Rolls-Royce Phantom V eight years ago. It has however been the best and only modification I have made to that car. I have now made this modification to the 1975 Mercedes 450SL and again, what a difference.

 The system I chose for the Mercedes 450SL was the Pertronix Ignitor electronic ignition (part 1885) in combination with the Pertronix Flame Thrower 1.5 ohm, 40,000 volt coil. The Flame Thrower coil is a must if you are going to make the modification. No, the coil does not look like the original OEM however, there are options to help that. More on that in an upcoming post. (For what it's worth, the Rolls-Royce received the Pertroinx Ignitor II system, which does not fit the 450SL. 

For the 1975 450SL, modifications will be needed on Pertronix Ignitor for it to fit properly in the distributor. The last I heard from Pertronix, was no plug and play version was going to be produced for this car as there was not enough demand as of yet.

The tachometer will also need to be reconfigured following the installation which is not complicated but once again it is not a simple plug and play as with many other cars that receive the system. More on how this is done in a future article.

Finally, you can decide either to leave the original Mercedes switch gear or eliminate it. I chose to eliminate it and remove the two resistors as recommended by Pertronix. If the resistors are kept inline, the Flame Thrower coil will not perform as designed, hindering the upgraded performance. Do however keep all your original components. Many collectors would like to have those quickly vanishing parts should you sell the car.

To keep the look of the car original, I have left the switch gear and the two Bosch resistors in place. 

Pros of the Pertronix ignition? A much improved idle and engine responsiveness, in addition to a slightly increased fuel economy. One particular note of interest was noticing that both the Rolls-Royce and the Mercedes delivered a different exhaust smell following the installation of the electronic ignition. It was quite evident to the olfactory that the combustion was more complete. 

Cons A little extra wiring will need to be done and a bit of modification to the Ignitor unit itself to seat properly in the distributor.