Ignition Coil

[novanick]

Hey fellas, dumb question perhaps.

My daily driver is a series III 88", sure enough the internally ballasted coil I'd been running had quit the other week. So I ordered up a replacement from RoverNorth. I went with the ProLine jobby, part number #PLE522.

My question is, the positive and negative terminals on each side of the coil, have two male connection tabs for each the positive and negative. I haven't seen this before. What's the purpose?

Am I under the impression that it is internally ballasted but actually needs an external resistor and the multiple tabs are for perhaps a 'hot switch' to bypass the resistor straight to the coil?

Thanks.

Nick.

[o2batsea]

I have no clue. Why would you not connect it just as the old one was?

[jac04]

It is fairly typical of a replacement coil to have double connections on each terminal. Some applications require additional connections. For example, my Weber carb has a fuel shut-off solenoid that runs off the positive side of the coil.

Anyhow, don't worry about it. As o2batsea said, just hook it up as it was.

[I Leak Oil]

With your coil not being specific only to Series trucks, some vehicles can run a fuel pump relay, tachometer, etc. off the coil. One spade for your usual ignition circuit, another set for ancillary equipment.

[TedW]

I thought that all the tabs were hot. Not the case??

[I Leak Oil]

I thought that all the tabs were hot. Not the case??

One is hot constant with the ignition switch on, the other side is intermittant with the opening and closing of the points.

[TedW]

One is hot constant with the ignition switch on, the other side is intermittant with the opening and closing of the points.

What's the best way to tell which is which?

[SafeAirOne]

One is hot constant with the ignition switch on, the other side is intermittant with the opening and closing of the points.

Well...yes and no. For the benefit of everyone else, I'll explain: Both terminals have 12v available at all times that the ignition switch is in the "start" or "run" positions.

If you were to attach something, say a light bulb, between the (-) tab on the coil (where the small wire to distributor goes) and ground, the light would stay lit so along as the ignition switch is in "run" or "start" position regardless of whether the points were open or closed--There'll always be 12v available there.

The problem is that if you hook up some accessory there, opening the points won't break the primary circuit, stopping the flow of electricity through the primary circuit, which is required to create the high-voltage in the secondary circuit of the coil, since the 12v of the primary circuit still flows to ground through the accessory.

It's like if you add a tee fitting (think 'electrical accessory') into the middle of your pressurized garden hose--Even though the spray nozzle (think 'points') on the end of the hose is off, you are able to get water flow out of the tee and as long as the tee is there, water will cointinue to flow through the tap on the side of your house (think 'coil') and out the tee fitting, regardless of whether the spray nozzle on the end of the hose is open or not.

What's the best way to tell which is which?

The white ignition wire should go to the (+) tab on the coil. The small wire to the distributor goes to the other (-) terminal. Just put accessories on the side that DOESN'T go to the distributor.

[TedW]

Well...yes and no. For the benefit of everyone else, I'll explain: Both terminals have 12v available at all times that the ignition switch is in the "start" or "run" positions.

If you were to attach something, say a light bulb, between the (-) tab on the coil (where the small wire to distributor goes) and ground, the light would stay lit so along as the ignition switch is in "run" or "start" position regardless of whether the points were open or closed--There'll always be 12v available there.

The problem is that if you hook up some accessory there, opening the points won't break the primary circuit, stopping the flow of electricity through the primary circuit, which is required to create the high-voltage in the secondary circuit of the coil, since the 12v of the primary circuit still flows to ground through the accessory.

It's like if you add a tee fitting (think 'electrical accessory') into the middle of your pressurized garden hose--Even though the spray nozzle (think 'points') on the end of the hose is off, you are able to get water flow out of the tee and as long as the tee is there, water will cointinue to flow through the tap on the side of your house (think 'coil') and out the tee fitting, regardless of whether the spray nozzle on the end of the hose is open or not.





The white ignition wire should go to the (+) tab on the coil. The small wire to the distributor goes to the other (-) terminal. Just put accessories on the side that DOESN'T go to the distributor.

So, what are the practical effects of having an accessory connected to the (-) distributor side? How will it effect performance / function?

[SafeAirOne]

So, what are the practical effects of having an accessory connected to the (-) distributor side? How will it effect performance / function?

Accessory will work fine. Engine won't run.

[I Leak Oil]

Thanks Mark. That's a better way to explain it.

[TedW]

Accessory will work fine. Engine won't run.

Interesting. I have a Pertronix coil, and to the best of my knowledge I have accessories connected to both sides (I'll check tonight) and the truck runs fine.

[SafeAirOne]

Let me qualify that--accessories that aren't designed to go there (the light bulb, for example) will not permit the power through the primary coil windings to stop when the points are opened.

[TedW]

Let me qualify that--accessories that aren't designed to go there (the light bulb, for example) will not permit the power through the primary coil windings to stop when the points are opened.

So, if stuff works without affecting the running of the engine then everything's good?

[SafeAirOne]

So, if stuff works without affecting the running of the engine then everything's good?

Yeah. Now I'm curious to know what you have hooked up to that side of the coil...