I have a 239 which I switched to 12v and this is the second time that I think the condenser has gone out. The last time the engine would not start, KI changed the condenser and it ran again. Recently it quit running again so I figure it might be the condense again. What would cause the condenser to fail? The only thing I can figure is that I have the coil wired the wrong way. Can someone tell me with a negitive ground, the positive side of the coil goes where>

 

The negative side of coil should go to the points. It’s also where you hook up a tachometer, if you want. You should also have a ballast resistor in line. Incorrect ohms will burn out condenser faster than you can say wha...

 

Positive side is hooked up to ignition switch via ballast resistor.

 

Going by all the threads about condenser failures on the Ford Barn forum, I'm going to guess you bought bad condensers. If you can't find any info here, do a search over on the barn. They list the good ones to buy. (NAPA?) There is a guy over there (Tubman) that reproduces the big brass can type that has great feedback.

 

Tubman's super-condensers are for 6v.

 

Thanks for the clarification Ross. I think Bubba lists the "good ones" to get from NAPA and probably other sources. I was thinking some were 12 volt part numbers?

 

I experimented a little bit with modern high voltage film capacitors used in electronics. The Model A and T guys figured this out a long time ago. Some of their forums go into details.

The standard "cut" in the range of capacitors for this size available today is 0.22uF, right in the zone of 0.20-0.25. A 400 to 600 volt capacitor poly film capacitor should do the job. 1000 volts wouldn't hurt anything.

The specs that make a capacitor suitable is a little more complicated than that, something called dv/dt, or voltage rise time, which is basically current handling I expect. Something the size of a match head isn't going to work. Ignition service is rough duty.

Thin, compact "metalized film" types though tempting may not hold up. Since vintage electronics is something that interests me I have some "Orange Drops", from Sprague. 716P, they work fine and everything looks good on the scope. They are pretty chunky, but they fit inside a distributor. I keep a points distributor and coil ready to go in case the Ignitor goes out, and an orange drop in the glove box. They are almost impervious to moisture.

Some way of supporting the leads and protecting them from work hardening and breaking might be a factor, or simply soldering stranded leads on. Larger sizes work well for noise suppression on generator armature and at voltage regulators. A lot of people leave these noise suppressors out but they should help VR contact points last a lot longer.

Anyway these types of high voltage capacitors are a really good alternative for those frustrated with the lack of good replacement ignition condenser parts.

N.O.S. are a crapshoot and are not improving with time (storage conditions - humidity - maybe factors) and need to be tested to weed out duds, most people have no way to do this. A DVOM will not really work for testing high voltage ignition condensers. There isn't much call for high voltage capacitors in modern electronics these days, but there should be several different suitable kinds available if you look around.

 

Just adding my 2 cents. I switched my truck over to a Pertronics system. No points, no condenser. Has worked well so far.

 

Excellent explanation and work on this Tedster! I really liked the term "orange drop". I haven't heard or thought about those for a long time. Thank you for writing it up!

 

My thoughts too. I have ran various Pertronix units over the years and really like them. Plus you could probably get rid of the ballast resistor or resistor wire to the coil. The directions with the unit you receive will tell you for sure.

 

I ran into 2 bad condensors right out of the box with my truck from our usual supply places before finally ordering the Napa ones (for 6V) and getting it right. So the internals could just be junk and not last long at all, or fail outright.

I've used Pertronix (most recently in my 65 Galaxie's 289) and also Hot Spark (on older Volvo builds) with great results. Externally it looks the same, so people will be none-the-wiser if you are worried about the original look. And in the long run cost-wise, it's almost a no-brainer, too, as it doesn't cost much more than a couple of condensors and a set of points.

 

Thanks for the assist. Do I wire this ballast resistor directly into the wire from the switch to the coil?

 

Yes sir,
The resistor goes in series between the ignition switch and the + terminal of the coil. And if you have an "I" terminal on your starter solenoid relay you could also run another wire from it to again the + terminal of your coil. So you would end up with two connections on + terminal of the coil. If you add this wire, when the engine is cranking, it will bypass the resistor and provide full voltage to the coil for easier starting especially when the engine is cold.

 

Agree with Hooler 1. I did not need the ballast resistor on mine. In fact it would not run when it was connected.

 

I don't mean to appear stupid, but I am not an electrician. What does putting something in series mean? Do I just cut the wire the runs from the switch to the coil and put the resistor in that line?