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Old 10-04-2012, 06:38 AM
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1972 SBC - ignition / condenser

guys - i have a 1972 monte carlo i am battling with to get running after sitting for over 5 years. It cranks and barely fires. one of my thoughts is that i have a weak spark. i have replaced coil, condenser, rotor, cap, points and wires. my question is where does the wire from condenser attached to the coil bracket go? positive or negative terminal??

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Old 10-04-2012, 01:52 PM
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Does your coil has internal resistance, or its external?
How is the gap on the points?

You mention "barely" fires, have you checked for spark from coil to rotor? From rotor to plugs?
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Old 10-04-2012, 02:25 PM
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well i guess i'll show my ignorance - I don't know if its internal or external resistance.

The points are set to 0.019. the spark, when testing with new plugs grounded to the block, just seem week, and not always a blue spark.
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Old 10-04-2012, 02:38 PM
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Condensor wire would go to -Neg side. Not sure what "elchopperfreak" is talking about, 'internal or external' resistance? Can only be internal resistance. Maybe he intended to say Coil in cap = Large cap HEI or external coil Small cap HEI.
Hate to suggest this since you've replaced everything but, an upgrade to an HEI Distributor would've been better.
Info >> Ray's Chevy Restoration Site -- HEI Conversion
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Old 10-04-2012, 02:46 PM
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Points are pretty sturdy, Ive bought cars that for ages been in a farm and would give good spark after a bit of sandpaper..

You should get 12 volts to the positive on coil,where does your positive goes from the coil, straight into solenoid? ( I terminal) Or to a rectangular ( mostly white) plastic piece with two terminals??
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Old 10-04-2012, 02:51 PM
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SS
Maybe the term is not the same, ( I believe its called "resistor" in english) but will double check..

57
Ok.. Checked, its called a Ballast resistor, what I meant is that if your new coil uses ballast resistor or not..
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Old 10-04-2012, 02:56 PM
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Quote:
Originally Posted by elchopperfreak View Post
Maybe the term is not the same, ( I believe its called "resistor" in english) but will double check..
Are you refering to the Resistor or Resistance wire?
Some do use an external Resistor.
GM uses a power wire with built in Resistance.
Both drop the voltage down to about 9V+ to protect the Points.
They also have a wire that provides 12V+ to the Points while cranking/starting.
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Old 10-04-2012, 02:58 PM
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Exactly...
That is what I meant..Resistor
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Old 10-04-2012, 03:01 PM
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If the Wire from the Starter that provides 12V+ while cranking is not connected it will have a weak looking spark. Usually a Yellow wire.
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Old 10-04-2012, 03:22 PM
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Found this on an old thread.just in case


Doc here,

"The - Side of the coil gets the wire going to the Distributer only (unless you have a Tach, then the Tach pickup goes here as well..)

The + side of the coil gets the wire coming from the solenoid "R" or "I" terminal . this is secondary Ignition hot ONLY in Crank or start mode..to verify, put a meter on the wires, the wire that has power only when someone "taps crank or start" is the one your looking for. This wire ALONG with one wire from the ballast resistor will go to the coil + terminal.

The other wire, you can verify by simply turning the key on..it should have power on it and go off with the key..This wire goes to the other side of the ballast resistor.."
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Old 10-04-2012, 04:55 PM
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Wish "Doc" was still with us, God rest His soul.
At least we have some of his wisdom to look thru. He was an electrical wiz.
Good find "elchopperfreak".
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Old 10-04-2012, 05:18 PM
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ok 57 lets clear this up...first the car should start with power comming from the ign sw only.. if u want to tie in the "I" wire thats up to u...it will go to the (+) on coil...
first 12v from ign sw to ballast resistor, out of ballast to "+" on the coil, (-) side of coil goes to dizzy.
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