The Ford Barn

52merc · 04-25-2012, 07:08 PM

ok guys on a 8ba with a coil that has external restrictor on it and the car is positive earth which side of the coil does the hot igniton wire go to the _ or the + ive been told by a # of people because its post to earth the hot ign goes to the _ side help thanks trev

George/Maine · 04-25-2012, 08:07 PM

Pos grd so +pos to points and -neg hot.

rotorwrench · 04-26-2012, 09:13 AM

You can still purchase the little polarity spark testers from various old car parts venders or you can use a pencil lead to check it. The little checker is plugged in between the coil's high tension tower and the coil wire. As George/Maine mentioned, start with "+" for the points connection and "-" for power connection. The old originals were marked with Dist & Bat so you wouldn't get confused about polarity. Some coils are off on polarity from the manufacturer so it isn't a bad idea to check them. They will give a hotter spark when polarity is correct.

I assume you are running a ballast for 12-volt operation. The 6-volt systems didn't require a ballast resistor for the 8BA family of engines.

jdl · 04-26-2012, 09:24 AM

Sponsored Links (Register now to hide all advertisements)

http://www.fifthaveinternetgarage.co...l_polarit.html

Checking Ignition Coil PolarityYou can test for correct polarity of the ignition coil by using a voltmeter. Connect the negative lead to the (-) negative terminal and the positive lead to the engine block.
Set the meter on the highest volt range (these connections are the same whether you have a positive ground or negative ground electrical system). The secondary winding's polarity, which you are testing, is determined by the combined hookup of the battery and primary windings.
Crank the engine over (do not start it) and the needle of the voltmeter should show an

upward swing to the plus or positive side (do not worry about taking a reading). If

the needle swings down to the negative side and gives a negative reading, your coil is hooked up backwards. To correct the polarity, simply reverse coil primary leads.

A coil with reversed polarity will have about a twenty percent lower output which may not show up at idle and low rpms, but can cause an engine to miss or stumble under load and at higher engine rpms.

04-25-2012, 07:08 PM	#1
52merc Senior Member Join Date: May 2010 Location: new zealand Posts: 1,054	8ba coil ok guys on a 8ba with a coil that has external restrictor on it and the car is positive earth which side of the coil does the hot igniton wire go to the _ or the + ive been told by a # of people because its post to earth the hot ign goes to the _ side help thanks trev

04-25-2012, 08:07 PM	#2
George/Maine Senior Member Join Date: May 2010 Location: Mid coast Maine Posts: 1,878	Re: 8ba coil Pos grd so +pos to points and -neg hot.

04-26-2012, 09:13 AM	#3
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: 8ba coil You can still purchase the little polarity spark testers from various old car parts venders or you can use a pencil lead to check it. The little checker is plugged in between the coil's high tension tower and the coil wire. As George/Maine mentioned, start with "+" for the points connection and "-" for power connection. The old originals were marked with Dist & Bat so you wouldn't get confused about polarity. Some coils are off on polarity from the manufacturer so it isn't a bad idea to check them. They will give a hotter spark when polarity is correct. I assume you are running a ballast for 12-volt operation. The 6-volt systems didn't require a ballast resistor for the 8BA family of engines.

04-26-2012, 09:24 AM	#4
jdl Senior Member Join Date: May 2010 Location: California Central Coast Posts: 931	Re: 8ba coil Sponsored Links (Register now to hide all advertisements) http://www.fifthaveinternetgarage.co...l_polarit.html Checking Ignition Coil PolarityYou can test for correct polarity of the ignition coil by using a voltmeter. Connect the negative lead to the (-) negative terminal and the positive lead to the engine block. Set the meter on the highest volt range (these connections are the same whether you have a positive ground or negative ground electrical system). The secondary winding's polarity, which you are testing, is determined by the combined hookup of the battery and primary windings. Crank the engine over (do not start it) and the needle of the voltmeter should show an upward swing to the plus or positive side (do not worry about taking a reading). If the needle swings down to the negative side and gives a negative reading, your coil is hooked up backwards. To correct the polarity, simply reverse coil primary leads. A coil with reversed polarity will have about a twenty percent lower output which may not show up at idle and low rpms, but can cause an engine to miss or stumble under load and at higher engine rpms.