Neg or Pos Earth


I am checking to see if my 1959 P4 75 would be negative earth or positive earth please. I do not have aceess to the car at the moment to check where the leads go to so any help appreciated



Active Member
It would have been positive earth when new, and looking at the leads in the picture, the negative is routed through the armoured conduit to the front of the car , it is still probably positive to the frame . I would double check just to make sure there are no modifications outside the scope of the picture.


Well-Known Member
I have seen conversions to neg earth work fine except for one issue - if the coil terminals are marked '-' and '+' they can be polarity sensitive - make sure these connections are correct polarity.


Active Member
it would of been postive when new, but impossible to say now, in my experience most cars have been converted to negative earth