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...

[TedW]

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

Soooo, I checked my coil: it turns out that there is one black wire on one side that appears to lead to the dizzzz. The other side has a bunch o' accessories connected to it.

I have added my electric fan to the mix - to the side that has the other accessories.

Apologies for posting incorrect info!

Many thanks for the help!

Ted

[I Leak Oil]

So your one black wire to the dist. is just that....coil to points. The ganglia of wires on the other side happens to be the constant hot side.

Please...do tell what this bunch of accessories consists of! My truck's definition of accessories is a dome light and a backup light.:)

[novanick]

Ah sweet, thanks fellas. I just thought it funny that there was an option for an additional option on both the pos and neg connections. wiring something (like an electric fan) to the positive side makes sense. Either way, with a new coil, points, condenser and plug wires the trucks working great. Need to tweak the timing a little, but other then that A-1!

[SafeAirOne]

wiring something (like an electric fan) to the positive side makes sense.

Nice job on getting it running again. I don't have a distributor on mine, but all three 'no-start' issues on a friend's rover have all been condensor failures.

I was just going to say that the 2.6 ran it's electric fuel boost pump off the white wire on the (+) terminal of the coil but it's a bad place to power an electric cooling fan. Reason being is that after you turn off the ignition and stop supplying power to the fan, the fan turns into a little generator, sending electricity back up the line and keeping the coil powered (and the engine running) till the fan spools down sufficiently.

Having said that, that's exactly where my electric cooling fan is powered from. Whenever I turn my engine off, it takes about 2 seconds for the engine to shut down (my diesel fuel shutoff solenoid is powered by the wire that used to go to the (+) side of the coil back in it's gasoline-powered days).

[o2batsea]

It is my preference to operate switched accessories from a dedicated power feed. A wire jumped off the main fuse is better. The wire supplying switched 12V+ to the coil is awfully small gauge for accessories that are downstream. Best is a solenoid operated power strip.

[SafeAirOne]

It is my preference to operate switched accessories from a dedicated power feed. A wire jumped off the main fuse is better. The wire supplying switched 12V+ to the coil is awfully small gauge for accessories that are downstream. Best is a solenoid operated power strip.


That's the way it SHOULD be done--that white wire is tiny and there shouldn't be much hooked up to it at all. I attribute my fuel pump and cooling fan being connected to the white wire to laziness and temptation.