Going to set timing this morning.

uncljohn wrote: TH_Gremlin wrote: I took an inventory of my parts, and noticed the coil says "12V Resistor Required". Thinking about the previous work I've done, the original ignition wire was producing less than 12V of current, so I ran a different wire from the fuse-panel (that runs current only when the ignition is turned forward), which runs at a higher voltage than 12V. So it got me thinking... maybe I do need a resistor. Then I got to thinking further... the original wire wasn't over 12V... maybe this Gremlin already has a device on it to reduce the voltage going to the coil. Car is a 1977 Gremlin, 258 I6 engine (just to keep you guys from going back and looking for it) http://www.secondchancegarage.com/articles/images/ignition/ignition.gif A voltage reading at the Plus side of the battery will generally read 12 volt dc. A voltage reading at the Plus + point on the coil with the ignition on AND the points closed (engine not running) will generally read one half of that value, thus 6 volts. Why? Because of the function of the Ballast resistor limiting the current flow through the points so that they will not burn out. A voltage reading at the plus + point on the coil with the engine running has no particular meaning at all when it comes diagnostics or explanation. Why? Because that is how you measure dwell and a dwell meter converts that voltage reading into a number used to set the point gap calibrated as to the number of cylinders involved. The resistior by pass as shown is a means to supply FULL battery voltage to the coil when starting the car.  This can be done a number of ways but is generally done on cars using  a "Ford" type starter switch by connecting a wire from the start terminal on the starter solenoid to the + terminal on the coil. And AMC uses a Ford type starter solenoid. WHY? It helps to start the car when initial battery voltage is low for what ever reason. Usually when it is extremely cold out side. SO Yes you need a ballast resistor, properly installed and wired to work with the ignition switch. If your car already has an electronic ignition, then you will have to determine what wires perform what function you need and then use them to run the ignition you are installing. And it is doable. I  did it on my 1976 Hornet which was an I-6 engine and space limitations were resolved by using a points ignition on the V8 engine I used to replace it with.

If his factory wiring is intact, he shouldn't have to change a thing.

I've done exactly what TH is planning to do albeit on a V8 Hornet. I ditched the Motorcraft system on my V8 Hornet, swapping in  a regular coil and a points distributor using the factory wiring.  12 years later, it still runs perfect. His car should still have the resistance wire as part of the wiring harness. He'll have two yellow wires leading to the positive side of the coil terminating into one connector.  One wire is full voltage start, the other is the resistance wire for run.

Fluffy73 wrote: I've done exactly what TH is planning to do albeit on a V8 Hornet. I ditched the Motorcraft system on my V8 Hornet, swapping in  a regular coil and a points distributor using the factory wiring.  12 years later, it still runs perfect. His car should still have the resistance wire as part of the wiring harness. He'll have two yellow wires leading to the positive side of the coil terminating into one connector.  One wire is full voltage start, the other is the resistance wire for run.

The wiring diagram for the electronic ignition does not show a resistor wire as part of the ignition circuit in either the theory explanation portion of the service manual nor the electrical wiring diagram for the car.   It does show 2 yellow wires though, but neither is a resistor wire.

A conversion to points requires " an on all the time" 12 volts supplied from the ignition switch which would have to be FIRST supplied to the " BALLAST RESISTOR" installed for the conversion.  The function of the ballast resistor is there to insure that the points have a full life span as designed due to aprx. 1/2 of the supplied battery voltage be supplied to them when the ignition key is ON. 
This is determined as correct by making a measurement of the voltage with the engine not running but the points being closed about 6 volts at the + terminal of the coil. 

due to the function of the BALLAST RESISTOR there then would or could be circumstances where the car would be hard to start due to the LACK of full battery voltage being supplied. Be it cold, or weak battery or what ever.
This is dealt with by another wire that has full battery voltage on it ONLY when trying to start the car.
This is shown in the wiring diagram in this thread by the wiring labeled resistor by pass.  This generally is supplied on AMC cars using points by using the start relay, a Ford type start relay that has an ignition and a start  terminal as part of the relay.  The start terminal is attached to the + side of the coil to supply FULL battery voltage only when starting the car to compensate for weak battery.

That a point conversion can be installed and function for a period of time (undetermined time) is not  a concern,  the concern is doing it correctly.  That can be found by (when done) the voltage at the + side of the coil will read aprox 1/2 of battery voltage with the key on, the engine not running and the points closed.

I too have done the conversion, but it was done by using a replacement starter solenoid from an earlier model AMC car for a standard transmission application and then running a wire from the start terminal to the + side of the coil thus a second wire at the coil installed. 
The plus side is it works.
The minus side is that if automatic transmission, the car will now start in any gear as on a torque flyte automatic transmission there is a wire coming from the plug on the automatic that supplied a ground to the starter solenoid only when the transmission is in park or neutral.  That is the TIT on the bottom of the solenoid.
If that is on the car in the first place than the proper starter solenoid from say a 1972 AMC car or newer with points can be used.  The use of that solenoid will supply the start wire and be part of the neutral start circuit.
Unless you change to an automatic which does not supply that function such as a 700R4 you will either have to fabricate a neutral start circuit and include it or use a standard transmission starter relay and remember it will start in any gear.


Edited by uncljohn - Apr/24/2014 at 5:31am

Unclejohn please stop confusing them!!!  I'm calling BS. That's the same tired incorrect info just re-pasted here again.

AMC used Motorcraft which in some years that *DID* have a resistance.
What makes it worse or harder is the fact that the TSM is WRONG in some years.
I converted many of these things to various other systems, the most recent a 1982 - removed the Motorcraft, installed HEI.
Guess what-  - RESISTANCE!  So I had to be sure to get that GM HEI full voltage - luckily Motorcraft had both - full and reduced and I made a connector that fed the HEI from the full voltage lead of the Motorcraft system and problem solved.
Ya keep coming back with this BS about who knows what and the facts are plain and simple and just right there easy to check.  Doesn't matter how many times you quote the same stuff or paste the same pictures, it ain't 100% right.
I've worked on thousands of cars across more than 4 decades, I have specialized in ignition and electric systems. My 4.0 GPA and college degree otta mean a little bit of something when it comes to autos and electric work. I also held a maintenance electrician license for a city in Iowa for a while.  I DO happen to know auto electric  - and this poor fellow isn't in for the nightmare you indicate unless he tries to follow your posts.
The Motorcraft systems DID use a resistance for some years. I have the proof in my shop in the form of a ream AMC car.
With points it's going to depend on the COIL he uses as to whether or not a resistance wire or resistor is needed.
The AMC TSM has a lot of mistakes over the years in the electrical areas - the cars don't always match. And there's a perfect explanation for that - the TSM was preproduction. It did not always include changes found at the last minute. Few people have the supplements - which often include either preproduction changes or running changes.
Thus - the TSM may not match the car.
The 1980s is probably the biggest area where they had changes.
Just for kicks, a perfect example is the front suspension and steering specs - alignment specs.
Let's pick 1982 again - you open the TSM to the alignment specs and there they are. And you look at Motors, Chilton and others, great, they all match so this is the correct set of specs.
WRONG!
Motors, Chiltons, etc. all took their lead from AMC. BUT, once published they never ever looked back! They never checked for accuracy later. So, for 1982 AMC, Eagle for example, the Chilton, Motor and AMC TSM are all very wrong. Only the AMC TSM supplement has the correct alignment specs for 1982 cars.
I've found similar issues with wiring diagrams - I've wired enough cars, made enough modifications on AMC cars over the decades (I used to do it for a living and it's how I started in the 70s) that I've seen a few of their "boo-boos".
We need to stick to the electrical engineering and facts behind how the automotive ignition systems work and why some of the parts are there.
Ballast resistors or not, resistance wires or not, coil primary winding resistance measurements, Motorcraft ignition systems, with and without resistors over the years, etc.

How many can tell the REAL reason a points type system has a condenser?
I guarantee right now the first few answers will be dead-wrong. That's because they'll be based on "what you've always heard", or what unknowing teachers taught or what's on the misinformation stupid highway now, and so on. But much of it ain't correct.

Enough is enough - if you want or need a VERY simple plan that will be exact for YOUR car and will be 100% correct, let me know. No BS, no complex circles. Simple wiring diagrams based on real cars, real experience.

Thanks for the sanity, fluffy - you are correct.
Unclejohn, sorry but that's a big line of, uh, well...... and I suggest that for the safety of ignition systems, it not be relied upon. FACT is that there WILL be resistance in some electronic systems, period.
FACT is that you can't say that the voltage will be any given value because a ballast is a CURRENT limiter, not a VOLTAGE limiter. It's not a "carbon" resistor. You CAN'T measure it and know good or bad with no load. Granted with no load it will be lower than a plain wire with no resistor or resistance wire, but it won't be a specific given value.
Just like that instrument panel device is NOT a voltage regulator per se, but more of a current limiter in how it operates - the end result is similar so it's called an IVR.
Your reason the ignition resistor exists is off the mark.  Too simplistic.
 
That's that I'm just not able to deal with 'armchair EEs' this week.  I spent nearly 7 years working in an electronic engineering company and spent a lot of my working career doing this sort of work, but just don't have the energy or ammo to argue against the stuff I'm seeing now so never mind.
fluffy hang in there, don't be swayed, you are aimed right at the correct target.

1977 had BID ignition.  and  IIRC, it will have a resistance wire for it to run on, the HEI needs no resistance wire at all, it needs a full 12 volts all the time to work correctly.