65 Dart 273 Commando Ballast Resistor

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Vcode

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What is the correct looking and correct Ohms ballast resistor ( 0.5-0.6 OR 0.8-0.9) for a 1965 Dart 273 Commando with Dual point Distributor.
 
I'm sure it's the same ballast weather its a 2 barrel or 4 engine. Just went out and measured mine for an original 65 273 2 barrel car and it's .92 OHMS I'll try to get a pic of it later.
 
The factory single bal res is 0.5 ohm when used with single point dist.
 
What about the Factory Dual Point Prestolite Distributor I am asking for.
 
Let me look it up think it is 0.5-0.8 ohms hot. 100 point car should be this one. They have been superceeded also. FSM has all the info in it in section 8
s-l1600.jpg
 
What coil are you using? You want around 5amps going through the primary winding. Current = voltage /resistance. A "correct" ballast may overheat the coil and leave you on the side of the road.
 
Measure the primary coil resistance. Measure the voltage to the coil primary and calulate the ballast resistance needed. NAPA has some ballast resistors values to choose from to get close to 5amps thru the coil primary. Example: 10V to primary coil (some voltage drops thru circuit) ballast resistance 1ohm, primary coil resistance 1ohm. 10Volts/1ohm+1ohm=5amps.
 
A couple of comments.
- post #7 & 9 have incorrect info.
- measuring very low resistances [ less than a couple of ohms ] will give misleading results with a std DVM because they are not very accurate at low ohm readings. I have a special 'low ohm' DVM that is specifically designed to measure low resistance & sub 1 ohm resistances.
- using measured coil resistance etc to select the bal res resistance does not work because in operation the system is not operating 'statically'.
- the numbers quoted in my Motors Manual for 1973 Chry V8 engines is as follows: ign current draw, engine idling 1.9 amps, coil pri res 1.4-1.5 ohms, bal res 0.5-0.6 ohm.
 
A couple of comments.
- post #7 & 9 have incorrect info.
- measuring very low resistances [ less than a couple of ohms ] will give misleading results with a std DVM because they are not very accurate at low ohm readings. I have a special 'low ohm' DVM that is specifically designed to measure low resistance & sub 1 ohm resistances.
- using measured coil resistance etc to select the bal res resistance does not work because in operation the system is not operating 'statically'.
- the numbers quoted in my Motors Manual for 1973 Chry V8 engines is as follows: ign current draw, engine idling 1.9 amps, coil pri res 1.4-1.5 ohms, bal res 0.5-0.6 ohm.
You will find if using a non OEM low resistance coil and original resistance ballast will result in an overheated coil. This shows up after extended use on warm days and high RPM use. It will leave you on the side of the road.
 
That maybe so, but calculating the reqd bal resistor resistance using static numbers will give the wrong value.
 
What Bewy is talking about is correct. You have to be careful choosing the correct ballast and here's why. Often times when looking at resistors, the resistance value is listed as COIL resistance and not ballast resistance. That's why sometimes you will see a ballast advertised at 1.25 ohms, which is actually correct speaking in coil resistance terms. It's confusing.
 
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