Coil woes

[climber8483]

So the cruiser was running fine yesterday and then I turned her off for a bit and she wouldn't start up again. I checked fuel and then I checked spark and I didn't have spark. Coil was really really hot, almost to hot to touch. Went and bought a new coil today, but before installing it figured I would try to start it and it started right up. Coil does seem to be leaking oil, but the coil is only a month old, has probably 100 miles driven on it. I replaced the coil with the exact same model Accel performance yellow coil. (can't remember part number). The old coil had been in the cruiser since before I had gotten it so it is at least several years old. I am carrying a spare for wheeling this weekend, but what do the fellow cruiser mechanics think?

Brittain

 

[Degnol]

Well, you might tell us a little more about the ignition you are running. If you have the ignition from the '70 you need a ballast resistor or you will continure to burn up points or coils.
What say you? More info.............please!

Ed

 

[climber8483]

Sorry, I just realized that. I have a '78 electronic dizzy. I have an igniter that hooks up to the coil. I hooked it up identical to the old coil, (at least I am pretty sure I did). It ran great for the last month, but like I said it just died yesterday and wouldn't start up. And I did verify no spark on two different plugs.

Brittain

 

[Pin_Head]

I think you should test the coil before you just replace it. They aren't that cheap that you can just toss them.

I can count the number of coils that have failed on one finger and that one was a super performance, extra high plasma, flame blaster coil (with optional flux capacitor) that someone had left the key on. All the oil (probably PCBs) had bubbled out of it.

Coils run hot. That is not unusual. They run really hot if you run a resistor type coil without a resistor.

 

[climber8483]

It's free to replace, 1 year warranty. Does a '78 electronic distributor need a resistor?

 

[vk7ybi]

Depends on the type of coil.

 

[Coolerman]

A stock 78 ignition coil does require a resistor. It's primary resistance is 1.5 ohms. This would allow 8 amps to flow. According to their web site Accel includes ballast resistors with a lot of their coils.

The primary resistance of the Accel stock looking coil is only .7 ohms. It could theoretically allow 17 amps of current to flow. I bet it needs a resistor.

A comparison: a 1971 coil has a primary resistance of 3.2 ohms and does not require a resistor. It would only allow 3.75 amps of current to flow.

 

[climber8483]

The coil I have is the Accel Superstock part number 8145. It says it has a resistance of 1.4 ohms. What should my resistance be for my distributor setup? And to verify the resistance of my coil I want to measure from the positive post to the top of the coil where the plug wire hooks up right?

Thanks

 

[climber8483]

Those are heater motor blower resistors.

 

[webelk6]

Those are heater motor blower resistors.

Sorry dude,
the correct # is ru13

https://forum.ih8mud.com/40-55-series-tech/263966-ballast-ignition-coil-resistor.html

I gave you really bad part #'s

 

[climber8483]

So I took my meter to the coil Federated said I needed, they aren't showing a resistor and I double checked and my current setup doesn't have a resistor. I have 2.0 ohms when I go (+) post to (-) post and I have 4.85 ohms when I go (+) post to the plug for the spark plug wire.

What values should I have? If I need a resistor does it go from the ignition module positive side to the positive coil post?

Thanks

 

[Coolerman]

Are you running the stock 1978 Igniter?

The value for the + to hi tension lead you posted as 4.85 does not sound right at all.

Disclaimer: I have never installed the 1978 igniter/coil/dizzy I have. I have taken it apart to see how it works.

The stock 1978 coil I have measures 1.5 ohms from + to - and 13,500 ohms for the + to high tension tower. Double check your reading on the + to hi tension lead.

The stock coil is marked 12V-R on the top and printed on the side it states "Use with external Resistor" The 1978 schematic that I have shows a resistor is used, but unless there was some kind of in-line resistor I'm not aware of, the coil is hooked straight to 12V. Jim C.?

I would say the coil you have now will work as long as the secondary resistance is in range. Double check that reading.

 

[bsmith123]

resistance checks

Are you using an autoranging meter maybe the 4.85 ohms is actually 4.85K OHMs?, or 4.85 megaohms?


if it is only 4.85 ohms thats sounds like a shorted secondary coil to the case or shorted windings internally, either way it would not be good