Positive Ground to Negative Ground

I have a 55 400 and would like to change the electrics from positive ground to negative ground. What is the best way to go about it?

Thanks,

Bernardi

This change is straight forward.

1) Disconnect the battery and rotate 180 in the tray (assuming top post type and unless your cables are extra long).

2) Reverse the wiring on the ignition coil.

3) Reverse the wiring on the ammeter gauge in the dash (doesn't apply if you have an idiot lite).

4) Reconnect the battery with NEG grounded, POS going to starter.

5) Repolarize the generator per the service manual pg 14 "Electrical" section, "Installation of Regulator", or [color:"red"] momentarily touch a cable connected to POS on the battery to armature "A" on the generator.

6) If your regulator is only POS polarity, then you'll have to get a new one that is dual polarity (NAPA VR325). You can tell because you won't see a charge on the ammeter if it's the wrong type.

The starter, T-L motor and vacuum tube radio do not care about polarity.

Craig - Many thanks. Sounds simple enough I that should be able to handle it. Does the heater blower run backwards or doesn't it matter?

Bernardi

At this time my car is still a pos ground. I really have no problem switching it but; what exactly are the benefits? Someone told me that it is simply to run a more mondern radio or other modern accesories. Is that the only reason?

Tim

MBL

Re: blower motor (like starter) turns the same way regardless of polarity.

Re: benefits of changing to Neg ground: true, only for modern stereo or ignition; otherwise, don't bother.

One thing....if you reverse polarity the horn will suck rather than blow but the sound will be the same. Oh, and the headlights will cast shadows.

Ha, ha! In the same vein, the rear tail lights will dim when you step on the brakes. <img src="http://www.aaca.org/ubbthreads/images/graemlins/tongue.gif" alt="" />

BTW, modern DC electric motors normally will [color:"red"]NOT tolerate a change in polarity because they use solid state controllers.

Most modern motors use a permanent magnet instead of a field coil, Perminent magent motors change direction if you reverse polarity, if the field is wound it will not change direction , ie starter motor and torsion motor and the original fan motors.

When converting from positive to negative ground, don't forget to re-gap the spark plugs. Positive ground cars have a closer gap of around .028 while negative ground needs around .035.