Ballast Resistor Question

[Toy4Hal]

At the risk of showing my ignorance (what's new?) can anyone tell me if the ballast resister part number needs to follows the car or the engine? My 62 'Vette has a 1968 engine (at least the block is 68). I'm looking for a "spare" resistor: do I buy one for the 68 or the 62?

Thank you in advance.

Hal

 

[67HEAVEN]

I don't have the answer, but good question. Someone will know.

 

[Ron Miller]

For the engine (more specifically, for the coil & points used). The ballast resistor cuts voltage to the points to prevent early burnout.

 

[Ken]

I think they're all the same, Hal.

 

[Toy4Hal]

Ken, your up early!!!! is this a new trend??? Come on up if your bored. Playing with the "toy".


Roy, thanks for the info. However, your answer makes it more complicated!:cry I have Mallory Unilite Electronic Distributor (no points) and a MSD Blaster 2 Coil. Does that suggest I can elimate the Ballast resistor completely?

Thanks again.

Hal

 

[Ken]

From Hot Rodder's Bulletin Board...

Q. "While you guys are on this subject I have a question about ballast Resistors. I recently converted my points to electronic ignition should I keep the Ballast Resistor in circut or remove it for a better spark? It never went into details in the install notes about this."

A. "I CONVERTED MY STOCK POINT SYSTEM TO PETRONIX I AND INSTRUCTIONS SAID TO ELIMINATE BALLAST RESISTOR."

 

[Jack]

I'll take a stab at this ... in a general sense.

Whether you NEED a ballast resistor or not depends upon the COIL ... that is ... what voltage is the coil rated at at. On 12volt cars ... some came with coil that is 6volt ... some came with 12 volt coil. In general, if your 12volt system has a 6 volt coil then you'll need a ballast resistor to drop the voltage to the coil. Typically, those 12V systems' 6volt coil is designed to run continuously with 6volts at the coil ... but on startup mode will have a wire direct from starter solenoid that momentarily supplies 12 volts to the 6 volt coil. On those systems requiring a voltage drop in the run mode, some use a ballast resistor and some use a resistor wire. I can't tell you what's correct for your model ... I just don't know that specific info. And if I've got this wrong, someone please step in and correct me. Hope this helps some.
JACK:gap

-edit-pretty sure all the unilites require 12volts ... and I am sure all blaster coils are 12 volts ... you probably need full 12 volts all the time.

 

[Toy4Hal]

Jack, great information. here is what I found on the MSD site for my coil:

_______________________________________



[font=Verdana, Arial, Helvetica, sans-serif][size=-2]BLASTER 2 AND 3 SPECIFICATIONS[/size][/font] [font=Verdana, Arial, Helvetica, sans-serif][size=-2]Output Voltage:[/size][/font] [font=Verdana, Arial, Helvetica, sans-serif][size=-2]45,000 Volts Maximum[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-2]Operating Voltage:[/size][/font] [font=Verdana, Arial, Helvetica, sans-serif][size=-2]12VDC[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-2]Primary Resistance:[/size][/font] [font=Verdana, Arial, Helvetica, sans-serif][size=-2]0.7 Ohms[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-2]Secondary Resistance:[/size][/font] [font=Verdana, Arial, Helvetica, sans-serif][size=-2]4.7K Ohms [/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-2]Turns Ratio:[/size][/font] [font=Verdana, Arial, Helvetica, sans-serif][size=-2]100:1[/size][/font]


[font=Verdana, Arial, Helvetica, sans-serif][size=+1]Stock Applications[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-1]
[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-1]

[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-1]The following Blaster 2 Coils are supplied with a 0.8 ohm ballast resistor and a terminal and boot to fit most applications. The ballast resistor must be used with stock Points Ignition and Mallory Unilite applications.[/size][/font]

[font=Verdana, Arial, Helvetica, sans-serif][size=-1]NOTE: These are the same coils as the other Blaster Coils, except they are supplied with a ballast resistor.[/size][/font]

[font=Verdana, Arial, Helvetica, sans-serif]Blaster 2 - PN 8200 [/font][font=Verdana, Arial, Helvetica, sans-serif]Chrome Housing![/font][font=Verdana, Arial, Helvetica, sans-serif]
Blaster 2 - PN 8203 [/font][font=Verdana, Arial, Helvetica, sans-serif]Show quality Red Housing![/font]

​

______________________________________

It would seem to me, then, that I can take the regular balast resistor out of the circuit. is that how you read it?

Thanks again.

 

[JohnZ]

[font=Verdana, Arial, Helvetica, sans-serif][size=+1]Stock Applications[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-1]
[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-1]

[/size][/font][font=Verdana, Arial, Helvetica, sans-serif][size=-1]The following Blaster 2 Coils are supplied with a 0.8 ohm ballast resistor and a terminal and boot to fit most applications. The ballast resistor must be used with stock Points Ignition and Mallory Unilite applications.[/size][/font]
______________________________________



It would seem to me, then, that I can take the regular balast resistor out of the circuit. is that how you read it?

Thanks again.

Nope! Read the last sentence - "The ballast resistor must be used with stock points ignition and Mallory Unilite applications". If you go to the Mallory Unilite installation wiring diagram at http://mrgasket.com/pdf/1466.PDF , you'll see the same thing - "failure to use a ballast resistor to feed the coil will result in eventual failure of the Unilite module". If you look at the diagram for cars originally equipped with a separate ballast resistor (as yours was), it shows the Unilite module red wire getting a full 12 volts from the ignition switch side of the resistor, and the coil (+) is fed from the other end of the resistor, just like the MSD instructions say up above. Unless you want to fry the Unilite module, use the resistor to feed the coil.

 

[Toy4Hal]

John, thanks for being detailed!!! Could have been a problem.

Hal