This was what my kids called "Car Sitting" It usually was sitting in the driveway after getting home listening to the end of a report on N.P.R.'s "All Things Considered". It especially annoyed them when they had to wait for me because the door to the house was locked.
Leaving the ignition (red indicator lamp) on when the motor is not running WILL cause the points to burn up and or overheat the coil. There is actually a 50/50 chance that the motor stopped in a position where the points are open and no current is going through the circuit, but there is no way to tell from inside the car so you must assume that the points are closed and current is going through the points and charging the coil.
SLs made before 1968 have a different ignition switch than cars made after. The cars with the double sided key have a terminal (marked R) that turns on when the key is in the #1 position. The earlier cars do not.
I have found that the later switch will fit on the early lock with the single sided key, and have one installed in my 66, 230. The old style switch has screw terminals the later one has a round shaped plug in connector, so to switch the car over the terminals at the key switch would have to be cut off the harness and the plug in terminals will need to be soldered on.
When I used to part out old 108s and 114s I would cut off the plug connectors from the wiring harness so I already had one in my goody stash.
It is a lot of work, I wouldn't recommend doing this unless you have the dash apart already and are looking for something extra to do when you have it apart.
Just an added note;
Breakerless ignition kits do charge the coil when the key is on, but the motor is not running, at least the PerTronic kits do, not sure about the Crane kits, but it would safe to assume they do too. So even if the car has a breakerless kit there is still the chance of overheating the coil.
Al Lieffring
66 230Sl
Jones'n for a new gas tank
