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Discussion Starter · #1 ·
I will rewire 69 Cutlass 350 point ignition and would like to know where the resistor wire supposed to go. Schematics I found for 69 GM cars have resistor wire go to coil together with one wire from starter solenoid.
My car has resistor wire go to solenoid and then regular wires #16 ?go to the coil. Can anyone tell me what is a correct way to wire it ? What voltage should be at the end of a resistor wire with ingition on ?
 

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This silliness is necessary because all points systems are a throwback to the ancient 6V power supply of eons past. If yo supply 12V to a set of any points, it will fry them in short order. The resistor is there to reduce the voltage to somewhere around 6V. Install it anywhere in the "Run" wire going to the "+" side of the coil. The second wire that goes to the "+" side of the coil from the starter is there to give the supercharged 12V only on startup to help fire the engine off. It is only energized when the starter is turning. That wire goes to a special, second small terminal on a starter that is there only for that purpose. Many people don't bother putting this wire in on custom wiring jobs. Actually, if your engine is in the shape it should be in, the extra boost shouldn't be needed.
 

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Discussion Starter · #3 ·
Willys,
If I have 12 V at the coil with ignition on( not cranking ), does it mean that resistor wire is bad ? Do you have an idea how to fix it, because nobody in my area caries resistor wire. Do you know what is maximum allowable voltage so the points will not burn ? I can get some resistors and make it work but I need to get that right voltage.
Thanks,
 

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That reading is normal. Resistors will read full voltage across them when they are not under load. They only drop voltage when there is current passing through them. I'm not familiar with 'resistor wire', all the ones I have ever dealt with have been porcelain blocks with a resistor coil in them. Then I am not much up to speed on modern cars! These things dump quite a bit of wattage so get pretty hot. I can't imagine a 'resistor wire' being able to survive under this load but maybe it can. What does the resistor wire look like? Does it get hot when the key is on? What distinguishes it as a resistor wire?
 

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Discussion Starter · #5 ·
Wire is thicker insulated with like rubber( softer then plastic insulation )and is purplish in color and goes from ign.switch to starter solenoid.. It got hot and burned other wires so I will have to replace that circuit( ignition ). I will use those ceramic resistors, do you know what ohms should they have for 350 Olds engine?
 

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Olds 69 said:
Wire is thicker insulated with like rubber( softer then plastic insulation )and is purplish in color and goes from ign.switch to starter solenoid.. It got hot and burned other wires so I will have to replace that circuit( ignition ). I will use those ceramic resistors, do you know what ohms should they have for 350 Olds engine?
That wasn't a resistor wire for the ignition. It is a 'Fusible link' which late model cars use in in place of a circuit breaker to protect circuits. It is a small gauge wire that is just barely large enough to carry the designed maximum current in the circuit so anything much past that will burn it out. Parts stores should carry fusible link but a better way to fix them is with a properly sized circuit breaker that will simply disconnect the circuit due to an overload rather than catastrophically fail like a fusible link. Yours was probably not overloaded at all, just got tired and fried. They do that.

Any ignition resistor will work on any points ignition.
 

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14 guage from the ign to the resister block and then to coil. The wire from the solenoid should not go through the block as you want the full 12 volts while it is cranking.
 

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Discussion Starter · #10 ·
[email][email protected][/email] said:
That wasn't a resistor wire for the ignition. It is a 'Fusible link' which late model cars use in in place of a circuit breaker to protect circuits. It is a small gauge wire that is just barely large enough to carry the designed maximum current in the circuit so anything much past that will burn it out. Parts stores should carry fusible link but a better way to fix them is with a properly sized circuit breaker that will simply disconnect the circuit due to an overload rather than catastrophically fail like a fusible link. Yours was probably not overloaded at all, just got tired and fried. They do that.

Any ignition resistor will work on any points ignition.
Is it possible that someone put there a fusible link wire instead of a resistor wire ? It has been like that since I got the car and it was running good till recently. Wire got hot and fried insulation on two other wires but it still gets voltage trough to the coil, but not under the load, i suppose , that might be why it dies after cranks up.

If I understand dit, I should run # 14 wire with ceramic resistor from ignition to the coil and protect it with a circuit breaker. How many amps should circuit breaker be for ?
 

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No, just the resistor will be fine. Fusible links are usually just put in the main power lead to your fusebox/distribution center. Sounds like GM cheaped out and used a fusible link in place of the ceramic resistor. Really bad idea, as are all fusible links for that matter but saved a few $0.000,000,001/ car which thrilled the accountants.
 

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Hey folks.On these older GM cars the so called resistor wire runs on that horizontal plastic rail attached to the firewall.It has a cloth like insulation,whitish colored and does come from the starter to the ignition coil.The length is calculated to give the proper voltage drop.
 

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Discussion Starter · #13 ·
Thanks guys for helping me with this.
Is it ok to use lower gauge wire then is called for, like use #12 instead of #14 , #14 instead of #16 and so on? Will it cause me any problems ?
I will be rewiring a lot now and wires cost about the same.
Paolo, GM diagrams shows resistor wire from ignition switch to coil. I would like to know, what cars have res. wire done like you have mentioned ?
Thanks,
 

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Olds,

(resistance wire to the solonoid.....very very weird)

anyway, on to the fix and the check..

12V to the $5 Chrysler ceramic resistor with screw in terminals, alligator clip your volt meter to the second resistor terminal and to the + side of the coil.

start the car, at idle it will read ?8-9V,,,, above 1200? rpm the voltage reg and alt will boost it to 12V for a better burn

reads per above, all if fine

second wire,12V from the starter solonoid = "insurance?", = lots of base timing/hot motor/weak batt/left the lights on/etc....the extra 4V and amps thru the circuit help the motor catch and start quicker. again, it only has power when the starter is turning

you can wire it to the coil + or to the downstream terminal of the of the resistor
 

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Discussion Starter · #19 ·
Re: Olds,

red65mustang said:
(

12V to the $5 Chrysler ceramic resistor with screw in terminals, alligator clip your volt meter to the second resistor terminal and to the + side of the coil.

start the car, at idle it will read ?8-9V,,,, above 1200? rpm the voltage reg and alt will boost it to 12V for a better burn

reads per above, all if fine

second wire,12V from the starter solonoid = "insurance?", = lots of base timing/hot motor/weak batt/left the lights on/etc....the extra 4V and amps thru the circuit help the motor catch and start quicker. again, it only has power when the starter is turning

you can wire it to the coil + or to the downstream terminal of the of the resistor
Thanks,
I've got ceramic resistor and when connected to battery it had 6.1 V , then I hook it up to coil and car was cranking but didn't start . Is it possible that resistor is not the right one ?
 
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