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Ignition Problem for the Books


Brian_Heil

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I thought I had seen the most difficult to solve ignition problem 25 years ago when the external ballast resistor filament was broken on my 1923 Buick and that little filament would make and break contact as it would heat up and cool down.  That one took several days until working into the late evening and I saw something spark as the engine quit in my dark driveway.

 

Here is headache #2:

 

Car was running poor then not at all, no spark, then weak spark, stall.  Then it would try to run.  I checked all the wires, cleaned all the connections.  Nothing.  New plugs cap points rotor capacitor coil.  Nothing.  Did find the loose banjo fitting on the fuel pump and fixed that.  Took the Marvel apart and didn't find anything wrong but it got a good cleaning.  I then walked the entire ignition circuit with my multi meter starting at the battery.  All the way to the points.  Hey, the points arm is dead.  The little leaf spring that provides spring load to close the points also carries the voltage and current from the points arm when they close and are grounded.  The leaf spring was rusty where it makes contact with the nesting arm that comes off the isolated grounding terminal on the side of the distributor.  That was it.  The leaf spring pressure is all there is to make the leaf have good contact with the nesting arm.  Not a great design so that interface needs to be clean.  There, I just saved someone 18 hours of frustration.

Edited by Brian_Heil (see edit history)
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Thanks for sharing that!  I used to have a 1971 Plymouth Barracuda convertible that would run well for ten miles or so, then die.  Of course, I would open the hood to look things over.  After a few minutes and not finding anything, the car would start right up and I would drive it home.  Turns out the pickup coil in the updated electronic distributor would get hot and go open circuit, then fix itself when it cooled back down.  Took me a while to find that one!  :)

 

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The saga has another chapter 

 

I still had some ignition issues after the leaf spring cleaning.  Run 100% then fall off then come back. 

 

Another afternoon of hunting.  This time I found the point head on the new points set, not securely riveted to the points arm.  You could spin it with your fingers.  Perhaps this rotating points head / poor contact was it all along?

 

A rap with a center punch on the back rivet head and all good.   
 

Fingers crossed. 

Edited by Brian_Heil (see edit history)
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It was more frustrating than it sounds.
 

Just the pressure of my test probe against the points head was enough to improve the continuity and get a good reading.  More frustrating is the point head would rotate around and have good and bad continuity as it ran and rotated to different angular locations.  Fooled me several times. 
 

This issue now tops the ballast resistor issue above for difficulty in finding. 

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  • 2 months later...

I never did a follow-up after the Nickel Tour in SW Ohio after my ignition saga. 

 

Great tour, great roads, great group.  Buick ran well like it always has.  Just shy of 600 miles for the 5 days.

 

Had a mystery flat.  Came out to a flat tire in the morning.  Put the spare on and got going.  Since it was the last day I waited until I got home to break the tire down.  This also lets me cuss in private as I re-mount the tire.  No leak found.  Tire still up weeks later.  Maybe a Ford guy wanted to slow me down and let the air out on me.

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