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coverted to negative earth
Posted: Wed Oct 01, 2014 7:10 am
by craig12
my 1953 morris has been coverted to negative earth , why would this have been done is there any advantage ? I am thinking of converting it back , the car is running and all appears well but I notice the fuel gauge is disconnected ., has anyone else felt the need to do this .
Re: coverted to negative earth
Posted: Wed Oct 01, 2014 7:16 am
by mike.perry
It has probably been converted so that modern neg earth components can be used. There is also less electrolytic action with neg earth
Re: coverted to negative earth
Posted: Wed Oct 01, 2014 7:18 am
by tysonn
Maybe last owner had a stereo fitted?
Re: coverted to negative earth
Posted: Wed Oct 01, 2014 7:54 am
by craig12
I will put my avo on the wire to the fuel sensor unit but I guess hes got a feed now on this wire and that's why its disconnected , can I alter this unit ? every thing else works but unless the dynamo polarity has been reversed im guessing it wont charge , will look into this to see just how far he went with this alteration , I would really like to keep standard , less electrolytic action , this is interesting could you explain this in more detail please
Re: coverted to negative earth
Posted: Wed Oct 01, 2014 11:54 am
by mike.perry
With a pos earth car there seems to be more deposits on the points and other components than with neg earth cars. This has something to do it the direction of travel of the electrodes.
Ok I have dug myself a hole and it is time to stop digging. Perhaps someone else can expain it a bit more scientifically
Re: coverted to negative earth
Posted: Wed Oct 01, 2014 11:58 am
by tysonn
Plenty on Google about it.Just look it up.
Re: coverted to negative earth
Posted: Wed Oct 01, 2014 1:36 pm
by craig12
so i see , other than the radio (i can get round this as im fitting a ipod doc) i see no reson to do this , so i think i will go back to standard (also saves the fuel sender unit problem) just wonderd why it was done in the first place
Re: coverted to negative earth
Posted: Wed Oct 01, 2014 4:07 pm
by Boomlander
I was told by an even older-timer that a positive earth system produced a more consistent and even spark at the plugs at the expense of some slight increase in electrolytic action between the battery and the body.......????????
Jethro is Positive Earth as the creator intended and has an isolator on the battery so it is disconnected when not in use but of course to add modern accessories like a radio or sat nav you would need to convert to negative Earth.

Re: coverted to negative earth
Posted: Thu Oct 02, 2014 2:19 pm
by craig12
the sat nav maybe a problem as i do use one a lot
Re: coverted to negative earth
Posted: Thu Oct 02, 2014 5:02 pm
by tysonn
Not really its all encased in plastic.No risk of shorting against the body.