Coil ballast resistor values

[280sl1968]

I'm a little confused by the value of the ballast resistor installed on my early 280SL.

The coil appears to painted black with an orange top which I have assumed (maybe wrongly) to be the original type 'black' coil.

I had therefore expected to see a 0.9 ohm ballast resistor fitted, but what's there is a white coloured resistor with a bracket showing Bosch P/N 0227901013. I haven't tested it, but looking up the specs, it looks like this is a 0.6 ohm resistor.

The Tech Manual suggests that a 0.6 ohm resistor was used in conjunction with a 0.4 ohm resistor with the blue coil and transistorized ignitions (which my car doesn't have)

Is the 0.6 ohm resistor therefore wrong for my car / does it really matter?

David

[Benz Dr.]

Black coils should use the .9 ohm ballast resistor. A .6 isn't that far from being right but you might want to change it if you can find the right one.

[garymand]

2 cents FWIW: The slightly lower resistance raises the voltage on your coil slightly.  That gives you a slightly hotter spark.  But your coil can accumulate a slightly hotter running temperture , which might reduce its life a slightly, probably not much as some never fail and, if its like mine, it is seldom run and less seldom run for extended time periods that might stress the coil with overly high tempertures.   Our coils are placed up front in a well ventilated location and clamped to a good heat sink.  All that helps to keep the coil's temperature down.