Dead Coil

[Anonymous]

What kills a coil? I had a Summit Street Strip TFI coil die today. The shame was I had just solved all the vacuum leaks and was cruising down the highway so nicely. Then the engine died. $180.00 in towing fees later, I had an old coil that I replaced it with and the car started right off. I swapped it out again just to make sure, no spark. I am now using a 20 plus year old coil and the car is running great. I know it wasn't heat, the coil is mounted on the shock tower. Any suggestions?
Thanks,
Ken

 

[CoupeBoy]

I know it doesn't help at all, but sometimes with electronics it really is binary

1= it works
0 = it's dead

Every electronic product ever made has at least one or two uncharacteristic failures.

-ron

 

[Anonymous]

Ron, you're right. I will pick up another as a spare.
Thanks,
Ken

 

[fordconvert]

What are you driving that coil with? What usually destroys them is they get left on. Most of the electronic modules will 'time out' and not stay on if they are not getting a signal from the pickup in the distributor. With points it was up to the ballast resistor to reduce the load if you happened to stop the engine with the points closed and left the key on. If you left it on too long both the coil and resistor would be stressed and perhaps fail.

 

[Anonymous]

Fordconvert, I am using the Summit Street Strip multi-Spark digital capacitive ignition box. I also have a DSII distributor.
Ken

 

[fordconvert]

You would think that setup should not have issues.

 

[lpardee]

Ken,
Have to be careful with coil selection when running capacitive discharge ignitions. My MSD unit had a list of performance coils that are incompatible with the MSD unit

If the primary has too much primary inductance, it will look like an open circuit to the fast risetime CD circuit. This can lead to dielectric breakdown of the coil.

With an epoxy coil, the coil is usually dead after one spike. The epoxy turning to a carbon track to ground through the case. Oil filled coils heal themselves after an arc, but still eventually fail. Not as instantaneously, but with annoying "missing" symptoms. They usually don't fail completely unless the oil leaks out.

Larry

 

[Anonymous]

Thanks Larry for the information. I learn something new on this site each time I log on it. Which coil did you findly end up with?
Ken

 

[lpardee]

Ken,

I honestly don't remember other than that it was oil-filled and for electronic ignitions . My age is showing when it comes to things I did 15 plus years ago.

IMHO whether the coil is wound for points or electronic ignition, and whether it is oil-filled, epoxy potted, or "E"-frame core probably makes more difference than manufacturer.

As an example, when I worked for K-mart in the mid '70s I was surprised to read that their epoxy coil was rated the highest in a Consumer Reports test of coils, and only cost $10!

Larry

 

[simon]

What kills a coil?

heat and vibrations, to answer your question.