Ignition coil

[Gordon Ray]

I'm working on a 31 Plymouth I'm trying to understand how a ignition coil works with a POS ground

[PFitz]

Welcome GR.

 

The wire going to the distributor is grounded through the points when they close. So, the  terminal marked positive on the coil is where you connect the wire to the distributor.

 

Paul

[nickelroadster]

An ignition coil works the same way with a positive ground as with a negative ground system.  It is possible to hook your coil up backwards and still have the spark plugs fire even though the condenser would not do too much.  The coil itself does not care which direction the current flows.

[Graham Man]

Are you just trying to understand, or is it not working?  If not working, let us know what it is doing or not doing, we love a good puzzle.

[RAH]

Gordon,

Actually this has been bandied over several times and the only thing of importance is where the secondary winding connects to what post inside the coil. On modern coils the power (+) goes to the + lead and the (-) lead goes to the points to ground. In a positive ground system as has been mentioned the coil could care less which is pos. or neg. The consideration is where the bottom end of the secondary connects inside the coil. Generally that should be the one that goes to the points instead of back through system power.

[Gordon Ray]

Thanks for the info, with the car having a POS ground I guess the coil puts out enough high voltage to create a spark at the plug then.

[C Carl]

Hi Gordon. Glad you joined us. Welcome ! As nickelroadster says, there are 2 ways to hook up the wires at the coil. The wrong way, it could run, but not well. Here is a picture of the consequences from backwards. Over 1000 miles into a long drive to 'Vegas at this point, with occasional frustration, and I am putting a new coil in it. But of course it was not the coil at all, just crossed wires. Sometimes it would run O.K., for an old car. Sometimes put me on the side of the road for a while. Driving through 'Frisco after crossing the Golden Gate Bridge was a nightmare on wheels. Once figured out, the old thing finally ran like a CADILLAC !! What a difference !! Can you show us pictures of your car ?    -   Carl 

 

P.S. : Since you have just joined this friendly helpful group, you will not have known that this is an unrestored, original 1927 Cadillac. It is fairly well-known here, but I am not sure if I have posted these pictures before. Anyway, these are for you.