Mini starter and the points ignition. Simple solution

[big2bird]

If you read muy post on Scotts headlight modification, you know I added a 3rd relay. This is for the ignition.
On the old tach drive points systems, a resistor wire feeds the coil, limiting the current to 4 amps. Upon start up, a contact on the starter shunts this to provide a full 12 volts at start up. It also provides an easier hot restart.
WHEN you install a mini starter on a points ignition car, you LOSE this function. Here is the cure.
1) Run yourself a new keyed hot from the spare tab in the fuse box to a relay under the hood. Jump from this same point to one side of an external ballast resistor. Since most 8 cylinder coils are 1.5 ohms, use a bllast resistor of 1.5 ohms. This leaves you with a total of 3 ohms, giving the desired 4 amps at 12volts.
2)From the other side of this "shunt"relay, run a #16 wire to the other ballast resistor terminal, and from that same terminal to the + side of the coil. The - post is always the point side.
3)To activate the relay, run a #16 black to a known good ground, and the other side of the coil to the starter. Splice in to the purple coil wire there.
Now, when you turn on the key, the coil is fed via the ballast resistor.
When you are CRANKING the car, the relay pulls in, insuring full voltage to the coil for easier starting.
I will ask TT to autocad a drawing to post from my sketch.

Shunt relay is on the left.

Ballast resistor.

 

[BRUTAL64]

If you read muy post on Scotts headlight modification, you know I added a 3rd relay. This is for the ignition.
On the old tach drive points systems, a resistor wire feeds the coil, limiting the current to 4 amps. Upon start up, a contact on the starter shunts this to provide a full 12 volts at start up. It also provides an easier hot restart.
WHEN you install a mini starter on a points ignition car, you LOSE this function. Here is the cure.
1) Run yourself a new keyed hot from the spare tab in the fuse box to a relay under the hood. Jump from this same point to one side of an external ballast resistor. Since most 8 cylinder coils are 1.5 ohms, use a bllast resistor of 1.5 ohms. This leaves you with a total of 3 ohms, giving the desired 4 amps at 12volts.
2)From the other side of this "shunt"relay, run a #16 wire to the other ballast resistor terminal, and from that same terminal to the + side of the coil. The - post is always the point side.
3)To activate the relay, run a #16 black to a known good ground, and the other side of the coil to the starter. Splice in to the purple coil wire there.
Now, when you turn on the key, the coil is fed via the ballast resistor.
When you are CRANKING the car, the relay pulls in, insuring full voltage to the coil for easier starting.
I will ask TT to autocad a drawing to post from my sketch.

Shunt relay is on the left.

Ballast resistor.

Good job! Does away with the FORD hot start fix.

 

[Theiskell]

Big bird,
When you say install a ballast resistor is that for cars that don’t already have one. I am in the process of this at the moment and from what I understand on my ’69 is that the wire from the firewall already has the resistor 9.5 volt (I think) and the wire from the starter is a normal wire. So would I need the resistor in my case?

 

[big2bird]

Big bird,
When you say install a ballast resistor is that for cars that don’t already have one. I am in the process of this at the moment and from what I understand on my ’69 is that the wire from the firewall already has the resistor 9.5 volt (I think) and the wire from the starter is a normal wire. So would I need the resistor in my case?

No. I did that to simplify what Scott had installed.
You could take a keyed hot from your fuse box, and use it to feed the relay contacts. Your "switched end " would feed the coil + terminal directly.

 

[Twin_Turbo]

If you run any kind of ignition box you will not need a ballast resisstor.

 

[Theiskell]

No. I did that to simplify what Scott had installed.
You could take a keyed hot from your fuse box, and use it to feed the relay contacts. Your "switched end " would feed the coil + terminal directly.

That sounds good. I thought I had it figured out in my head and then I read your post and just wanted to be sure. Here is what I am going to do make sure it sounds right. I will use the purple wire to pull in the coil on the relay and use a 12 volt switched power source to feed the coil from the switched side of the relay.

 

[Theiskell]

If you run any kind of ignition box you will not need a ballast resisstor.

Is the resistor wire only to keep from burning up the points? I am also thinking about getting a conversion from points to electronic ignition. I’m just not sure the money will hold out on the build this thing is killing me. Also if I do go over to electronic will I need a new coil?

 

[big2bird]

That sounds good. I thought I had it figured out in my head and then I read your post and just wanted to be sure. Here is what I am going to do make sure it sounds right. I will use the purple wire to pull in the coil on the relay and use a 12 volt switched power source to feed the coil from the switched side of the relay.

There you go.:beer:

 

[big2bird]

Is the resistor wire only to keep from burning up the points? I am also thinking about getting a conversion from points to electronic ignition. I’m just not sure the money will hold out on the build this thing is killing me. Also if I do go over to electronic will I need a new coil?

Yes. It limits the current to 4 amps. Most all V-8 coils are 1.5 ohms, so you use a 1.5 ohm resistor to get a total of 3 ohms. 12v/3 ohms = 4 amperes

The points unit properly curved will work fine up to 6,000 RPM.(crankshaft speed)

 

[Theiskell]

Thanks for the help on this guys