Installing a Pertronix electronic ignition in a 1955 50

Randy G

Member
Does a 1955 JD 50 have a ballast resistor? If it does where is it located? Checked my JD parts book and can not really find if a 1955 model does or not. The Pertronix instructions have a separate wiring for ones with or with out a resistor and I want to be sure I do it correctly. Its 12v neg ground.
 

Officially the 50 gas and 50 AF used just a 12V 3.0 ohm coil and no ballast resistor. The 50 LP used the 6V, 1.5 ohm coil and a ballast to enable bypass starting.
For simplicity a 12v coil and no ballast is simplest. To maintain high enough electrical system voltage to ensure a powerful spark. Use HD battery cables, do not bolt the ground to the battery box and install a 1000CCA group 31 battery.
 
No matter how it was set up originally, a lot can get changed over 60 years.

To be sure, before removing the breaker points, with the points CLOSED, switch on the ignition and check the voltage on the ignition switch side of the coil.

If the reading is close to battery voltage, there's no resistor in the primary circuit, if there IS a resistor, the voltage will likely read in the 6 to 9 Volts range.
 
Randy: I put several of these on tractors. Main thing to consider is a direct wire from you switch to the electronics. 12volt is needed and I always removed the ballast and also remove the auxially wire from the starter connector so I will not short out. You kit should be as the tractor ground is being used. Disconnect battery till all your wiring is in place. Your batteries will have to be charged as the electronic does not work with jumper cabling. These systems are hot as a firecracker and everyone I worked on never gave a minutes trouble. The key if correctly installing donut and hooking up wiring. best of luck Chuck
 
"These systems are hot as a firecracker"

A pertronix Ignitor is simply an electronic switch with more voltage drop across it during dwell time than a good set of points, and it's current handing ability is limited, therefore it cannot produce a spark any "hotter" (or even as "hot") as a good set of points with the same coil.

CID system or various electronic ignition boxes are another matter, but the basic Pertronix has none of that high-tech trickery, and is highly overrated, IMHO.
 
Yo Bob, to your statement

"A pertronix Ignitor is simply an electronic switch with more voltage drop across it during dwell time than a good set of points, and it's current handing ability is limited, therefore it cannot produce a spark any "hotter" (or even as "hot") as a good set of points with the same coil."

TRUE INDEED and to others who may not understand, the MOST IMPORTANT parts of that statement are "a good set of points" and "with the same coil"

A good set of points with absolutely no burning or pitting should NOT have a 0.6 voltage drop and the same stock coil wont yield any more spark energy then if their current was interrupted by points or a solid state device.

What I tell people is that if an after market high energy high voltage capable coil (which may draw more amps then stock coil) is used with an elec switch that can pass and switch MORE AMPS then points and if a wider plug gap is used that's when the elec switch can give you more bang for the buck and deliver a higher energy (more volts x amps) spark across a wider gap.

I agree if you use the same coil, the use of an elec switch isn't going to produce any more spark energy then if you have good clean non burned points. HOWEVER an advantage of an elec switch is that points continually over time get worse and have more voltage drop due to carbon burning and pitting unlike a solid state switch that doesn't deteriorate so much over time.

Its also true a Pertronix is NOWHERE near the quality and cant produce near the spark energy as a modern automotive high energy ignition.

I still like an elec switch (that can handle more current then points) on a tractor if used with a high energy high voltage coil and a wider plug gap AS LONG AS IT WORKS LOL because points begin to deteriorate soon as they are used and carbon and pitting eventually causes resistance and more voltage drop. HOWEVER you can file points and get back to the barn while if an elec goes bad youre screwed lol TO EACH THEIR OWN, advanatages and disadvantages either way

PS do you agree there would be that 0.6 PN junction voltage drop across an elec switch when conducting???? I'm rusty on electronics and solid state?????????????????????????

Fun sparky chatting with you Bob

JOhn T
 
(quoted from post at 19:56:31 11/14/16) Seems like the experts don't approve of the electronics.....

I never said I didn't "approve" of EI.

My point was that the basic Pertronix Ignitor is simply an electronic switch that replaces breaker points and is not anything like CID ignitions, HEI ignition, or other modern HOT ignition systems.

They are limited in current carrying capacity to basically that of a good set of points, ruling out using a super HOT coil, but various other electronic ignitions have a much higher current capability and dwell control enabling the use of much "hotter" coils.
 
In my description of "hot as a firecracker" I came to these conclusions from the following test.
1. Choked the tractor till it spit out black crude from exhaust. Took choke off and the electronic ignition fired and cleared the plugged and tractor started.
2. RPM range increased on all tractors with same carburetor settings.
3. Never matter what type plugs was used, hot or cold all different brands the ignition fired all of them.
4. Never had to change plugs as before
5. Took a hot running tractor put a garden hose water over the distributor and tractor continued to run.
6. Cold weather starting was simple without a concern for flooding.
7. Tractors never failed to start.

Now I don't know what term to use for all this but I would highly recommend electronic ignition. I installed on 7 different tractors and all successful.
 

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