Article first created: 5 Mar 2016


The original cars were fitted with a Lucas C40 dynamo.

Positive to negative earth

The C40 can be re-polarised if converting the car from positive to negative earth.

This is quite straight forward but I cannot remember all the steps.

The battery needs to be turned around

The dynamo needs to be repolarised by stroking the coil with a positive feed.

Dynamo Output

The C40 outputs a maximum of 20A.


This is black box unit mounted on the nearside inner wing. This unit regulates the output from the dynamo. Diagnosing a regulator is not so easy although I am sure there are methods. If I suspected a regulator was faulty, I just changed it. These units are easy to change.

Alternator conversion

Refer separate post about making a conversion (is quite easy)


Leave a Reply

Your email address will not be published. Required fields are marked *