8BA, 12v coil question
 

I have an 8BA in my '36 with a 12 volt system. The Tach is not working and it did before. Not sure what I changed. The Positive side of the coil is going to the distributor and the Tach wire is hooked to the same positive lug.

Should I have the negative side of the coil going to the distributor and the Tach wire hooked to it?

Re: 8BA, 12v coil question
 

If your vehicle is wired as negative ground, the negative side of coil runs to the distributor. If positive ground, then that terminal to the distributor. Check your battery for which side is run to ground as a guide. Like many others, when I switch to 12v, I switch to negative ground. When built your car was 6v with positive ground.

Re: 8BA, 12v coil question
 

Assuming you have a 12V NEGATIVE grounded battery installation, the negative side of the coil should go to the distributor. The sensor wire from the tach should also be on the side going to the distributor.

GB was posting while I was typing

Re: 8BA, 12v coil question
 

Just Checked. Definitely Negative ground on the 12 volt system, so I have my coil in backwards.
Great way to remember, Negative Ground, Negative from the coil to the distributor.
Thanks

Re: 8BA, 12v coil question
 

Yep.
And the tach is always connected to the distributor side of the coil. The tach measures RPM by counting the pulses created by opening/closing of the points in the distributor.