Low HT Ignition / Coil Spark Voltage
All Models With Ballast Ignition Systems
Many enthusiasts in the search for better engine performance install a Lucas model 101B “Sports” coil. However, on a ballasted ignition system such as fitted to later Triumph models, it is imperative that the original coil be substituted only with one that is compatible with the ballast circuit voltage of 6Volts. These coils are generally stamped with 6V on the coil base and will state on the label, “use only with ballasted systems”. The Lucas “Sports” coil is designed for non-ballasted 12V systems and perform poorly at the ballasted circuit voltages of 6V -7V.
When replacing coils ensure that the correct polarity is observed and be cautioned to pre-1965 models having battery polarity reversal. (IE: positive ground vehicle circuit changed to negative