Extracts from a report on a Racemettle High Torque Starter in Comparison to the original


This independent report was made on a Dolomite Sprint but is typical of starter performance across the full range of our units.


Report by Mr P K Wilbraham C.Eng. MIEE

Subject : Racemettle RAC406 and Lucas 2M100 Starters on 1980 Triumph Dolomite Sprint



To quantify the effect of replacing the original starter motor with a modern high torque unit.



The Lucas 2M100 starter was designed over 30 years ago and like many units at the time its performance was marginal when originally installed.


The poor performance manifested itself in various ways such as sticking solenoids and poor cranking speeds. When the unit gave problems it was a difficult job to remove and replace due to its location on the Sprint.


The original starter had just been overhauled but still gave uneven cranking speeds when observed from the engine cooling fan.



The results of the tests on the two starters were compared using the same instruments under the same conditions and so are acceptable for comparative purposes. Physical errors were minimised by taking care during the readings of the meters and by averaging of three readings.



Cable resistance by test current = 0.0032 ohms


Lucas 2M100


   Volt drop on starter cable 0.41 Volts

   Current taken by starter motor 0.41/0.0032=~128amps



Racemettle RAC406


   Volt drop on starter cable 0.195 volts

   Current taken by starter motor 0.195/0.0032=~61amps




The replacement high torque starter was approximately half the weight of the original one and physically smaller.


The replacement unit took less than 50% of the running current taken by the original equipment and produced a faster and much more consistent cranking speed. It can be used as a direct replacement for the original and is much more efficient.