positive or negative earth...

[evonaut]

is there a definitive answer as to whether a late 69 cooper s would have been negative or positive earth? the car has always been negative earth but now is the time to change if required.

i have opted for a dynamo system instead of upgrading to alternator

thank you

[rich@minispares.com]

I would have said 100% negative earth by then

[360gts]

69 cars still had the positive earth with the dynamo...even early 1970 MK3 models had "P" earth...
If the dynamo that is on there has Negative earth you will need to change the polarity of that dynamo...simple task. Booster cables and a fully charged battery....otherwise...just pick up a regular dynamo from any early vintage.

[rich@minispares.com]

I am quite often wrong...........

[woodypup59]

With a dynamo you can have either polarity.

At worst, all you have to do is re-polarise it if the red light won't go out.

But an alternator is almost bound to be -ve earth, and if you have a tacho, they are polarity sensitive too.

[evonaut]

the dynamo is new so should be easy to integrate within that system...... battery has not been connected as yet!

thank you all for input!

evonaut

[minimans]

good on you for staying with the dynamo!

[dklawson]

If you are fitting a new control box with the dynamo, be sure to clean its internal contacts. Some of the modern parts available today are shipped with a protective (insulating) coating on the points.

[ianh1968]

I am quite often wrong...........

Nobody's perfect...

Except me!

Who let him in here?

Ian