66 austin healey sprite

[jusadawg]

Was wondering how to charge a positive ground battery? Any different from charging a reg battery? And how hard it is to convert it over to a neg ground?

 

[jlaird]

Ahh, humm. Neg ground positive ground is how the batt is hooked to the car not how the batt is.

Neg ground, neg lead goes to firewall.

Pos ground, pos lead goes to firewall.

All else is the same concerning the batt.

 

[ncbugeye]

In fact I recently did a pos-earth to neg-earth conversion and am still using the same battery....

 

[spritenut]

Same to jump or charge, + to +, - to -.
Changing to negative ground involves a few steps but can be done easily.
reverse the wires on the coil (low tension)
flip the generator polarity by arcing a wire from the new hot side (+) of the battery to the field terminal on the generator (small terminal) 3 or 4 arcs is all it takes.
Reverse the internal wires inside the tach.
There is a spade terminal with a wire on it and a resistor right next to that terminal inside the housing.
Unsolder the resitor and wire and flip them.
Now hook up the battery with it's new ground.
Check the blower motor, if it sucks air out of the car just change the wires at the motor. Most do not need the heater flipped but I had one that did.

 

[mxp01]

Can anyone tell me if it is possible to hook up a modern radio in a positive ground car? Does the car's polarity have to be reversed in order to hook up a modern radio?

MXP

 

[john_j]

Can anyone tell me if it is possible to hook up a modern radio in a positive ground car? Does the car's polarity have to be reversed in order to hook up a modern radio?

You don't have to change the car's polarity but you do have to make sure that the case of the radio is not touching any metal parts of the car.

Most radios only have 1 power wire and use the case as the return, so in a + earth car with a - earth radio you need to connect the power input to + (the body) and the case to -(the battery via a fuse), so you have to make sure that where the case of the radio goes through the hole in the metal dash, there is no contact and if there is a mounting stud on the back of the radio you do not attach this via a perforated metal strip to the body.

 

[fmichaels]

that includes the antenna. don't plug the antenna directly into the radio on a positive grounded car... the antenna must be isolated from the radio. this can be done using a ferrite donut. i've done it before and it works but you must make sure the radio stays isolated from all metal parts of the car.

 

[mxp01]

How about the speakers?

MXP

 

[racingenglishcars]

Speaker, two wires, and only a signal at that, no problem.

There is however a theoretical problem with the antenna. It has to do with the antenna staff being normally surrounded by a ground. If the radio is installed with the opposite ground, the antenna staff is surrounded by the same polarity. They work ok, but not optimal.

Donn.

 

[Jim_Gruber]

Don't even think about putting in a modern radio of any type unless you change over to negative ground. All it takes is a fraction of a second and psst/pop expensive radio is gone. I changed Bugsy my '68 - ground with a 1098 positive ground engine.Took about 5 minutes to do. Believe it or not engine doesn't care if positive or negative ground. Buy a replacement tach if you don't want to go to the trouble of swapping wires in the tach and then use any radio you want.

 

[fmichaels]

i would agree with jim about the split second, but it can be done. as for speakers, be careful there too because you can ground through the speaker frame on some speakers.