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Ignition Coils - no Spark

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Brock69

Member
Hello - I need your help

I went to start my twin 1973 318 engines and neither one of them would fire

Pulled a spark plug held it to ground cranked engine - no spark
Pulled coil wire held it to ground cranked engine - no spark

There is 13.50 v at the + side of the coil. Using a screwdriver and Ign Sw on I found sparks at the points.

Put a jumper wire on the - or points side of the coil - held coil wire to grd and with the other end grounded it off and on- no spark.

The + side of the Coil is connected the new Ballast Resistor. The - side is connected the points.

All of this tells me that the Coil is no good. So I went and bought a new one - still no spark

The only thing I have not done is to replace the Points and Condenser. They were new last season.
I have used 3 different Coil wires They are not new.

Any help will be appreciated
 
The coil's primary side is saturated during point closure (via taking the circuit full circle, so to speak).
As the points break, the primary side field collapses, causing the secondary field to produce the high output ignition spark.
The condensor acts as a suppressor or capacitor, which stores energy until the field collapses.
Basically, this creates a one cycle AC transformer..... resulting in a secondary high voltage output.

Through a process of elimination, you should be able to pin point the problem.

Try installing new condensors.

Also, when testing, use a spark plug wire connected directly into the coil.
All we're doing here, is taking the distributor cap and rotor out of the equation.
You will get one spark per every cylinder this way..... otherwise, you wait until that particular cylinder comes around via rotor position.
 
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I have just realized that I set the point gap to .035 and I believe that the proper gap should be .020 ???

I assume that the gap is too big for the sparks to jump ???

I was using the # 1 spark plug wire

Your thoughts are appreciated
 
The spark that you see at the points has no bearing on the high voltage spark. This would be a relatively low current/low voltage.
Also, point gap is an estimate only of correct dwell angle.
Set points by dwell angle, not gap!

.
 
Rick is correct but why not get rid of the points and put in a Pertronix conversion kit? I haven't heard of anyone still running points for at least 10 years.

Dan
 
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