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Changing From Positive Earth To Negative Earth On 65 Mini


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#1 1965 Classic Mini

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Posted 22 July 2014 - 12:45 PM

Have tried unsuccessfully to make the switch....what am I doing wrong ?

Swapped battery terminals, shorted the dynamo terminals, swapped the coil connections......engine spins but will not fire up. Resorted back to positive earth and all works fine

Looking at fuel pump - think it PD type as it has 2 electrical connections is it a simple case to swap these connections or am I still making a complete mess of what should be a simple task ?

Any assistance much appreciated



#2 Guess-Works.com

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Posted 22 July 2014 - 12:50 PM

IMO, it's not worth swapping over from +ve earth to -ve earth unless you are moving away from a dynamo to an alternator.  There is no other benefit for doing the swap.

 

And if you are changing to an alternator, there's a lot more wiring which needs to be unravelled and also the isolation of the control box.



#3 1965 Classic Mini

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Posted 22 July 2014 - 02:09 PM

Thanks....I will be changing to alternator over the winter  - which I know will entail more wiring issues. First stage is just to get it to work as negative earth. So any help resolving this issue would be great



#4 Gr4h4m

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Posted 22 July 2014 - 07:27 PM

http://www.minimania...trical_polarity

 

 

You also have to change the voltage reg box if switching to an alternator. their is a How to somewhere. I gutted a spare one and used some link wires to do the conversion in side the box then put the lid back on. looks standard from the outside.



#5 Orange-Phantom

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Posted 22 July 2014 - 08:19 PM

Nice info the Gr4h4m!

 

I was under the impression that the change from positive earth to negative earth was to stop the galvanic corrosion of the bodywork. 



#6 1965 Classic Mini

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Posted 23 July 2014 - 07:49 AM

I had heard that changing to neg earth had benefit of slowing the rusting process. My reasons are to be able to fit a radio and ultimately an alternator



#7 Guess-Works.com

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Posted 23 July 2014 - 07:58 AM

Although the above may have some basis in truth I think it was more to do with the fact that accessories were more commonly available in -ve earth format and the introduction of alternators in the motor industry. 



#8 Gr4h4m

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Posted 23 July 2014 - 02:56 PM

I changed so that I could use negative earth accessories, and as they become vital for the engine to run I switched to an alternator too.



#9 Orange-Phantom

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Posted 23 July 2014 - 05:31 PM

Very true!  Not many accessories made for positive earth!



#10 Gr4h4m

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Posted 23 July 2014 - 11:44 PM

Esp megajolt :)




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