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Battary cut off switch


Freshman Member
I just got my BN-2 back together, and I am not getting spark. The car has been converted to negative ground, and I was wondering what I need to do with the white wire with the black strip. Currently it is disconected at the cut off switch, but it is hooked at the coil with a lead going off to the distributor. Please help, thanks.

Dave Russell

Yoda - R.I.P
A couple of thoughts.
If the white-black wire is disconnected at the battery shutoff switch, it would be good to make sure that the loose wire end is well insulated from everything. If it touches ground the ignition will be disabled (points grounded). Better yet, disconnect the coil end of the same wire & tape it back.

When you reverse battery polarity, the ignition may work better if you also reverse the coil's polarity. Remove the remaining white-black wire from the coil CB terminal, remove the two white wires from the coil SW terminal.

Reconnect the single white-black to the coil SW terminal. Reconnect the two white wires to the coil CB terminal.

Some fuel pumps are polarity sensitive. Solid state pumps & some later SU pumps may be damaged if battery polarity is reversed. If it is an SU pump that has an arc suppression diode, the diode will be damaged & the pump's contact points will quickly burn. Older style SU pumps that have a capacitor instead of a diode will not be damaged.

Some replacement heater motors will run backward if the polarity is reversed. The original motors will run correctly either way the power is connected.

The generator field must be "flashed" to reverse it's polarity the first time the battery is connected with the new negative ground connection.

Assuming that all of the "reversal" stuff has been done & that the car has been running ok, I would check the white-black wire from points to battery switch to make sure that it is not grounded.

If it has never run, also make sure that the points are not grounded by their mounting hardware/insulators, & that there is about .015" point gap.

Good luck,
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