Hope someone can help me. I have a 1992 Mercedes 300-24 R129 and have had 3 Rotor arms burn out on me in six months, the last one lasted an amazing three weeks!!! I have replaced the cap and the coil but this has made no difference.The bakerlite is burning away in exactly the same place on all three rotors which is just by the brass contact that takes the spark to the distributor segments. It seems that the spark is far too "hot" for the rotor. Any ideas will be very welcome. Many thanks.

Royboy666