Hi Naj,
This is interesting as when I purchased my car it had 2 ballast resistors fitted in tandem ( can't remember but l think they were both 0.6). I never liked that look so instructed them to replace it with a new one that I bought 0.9.
My car didn't start so well so l then asked them to change back to 2 in tandem and gave them another we 0.9 ballast resistor to fit. So now l have 2 X 0.9. By the way l have the red ignition coil.
It starts better but l feel it was never as good as before. I then read that originally the 280SL came with a 0.6 ballast resistor was contemplating have them try that.
I guess after reading your post l should leave it as is or replace them with a single 1.8ohm ballast resistor?
Appreciate your thoughts?
Hi, Rob,
The red coil is a replacement for the original black coil.
The red coil should be used with a 1.8 ohm ballast resistor. The original black coil used a 0.9 ohm resistor.
Does your 1970 car use a transistorised ign system? Don't know if the RHD cars ever used them?? The US spec cars did.
The transistorised ign system uses a much stronger coil (originally blue) and used two ballast resistors in series, a 0.6 ohm and a 0.4 ohm. One of the resistors is bypassed during cranking for easier starting. The bypass feed comes from the extra (live when cranking) terminal on the starter.
naj