12 volt conversion.

billford8N

New User
If i use a 12volt coil in the conversion, which mounts mounts on top of the distributor, do i need to use any resistor at all? Can i bypass the terminal block resistor and just use the new style?
Using the term block resister as a 1st primary resistor and then using the new one as a secondary, in line between terminal block and coil, is putting two resistors in line before the coil. [b:a49d31dfd8]Isnt that gonna knock the voltage down too low??[/b:a49d31dfd8]
Some of the wiring diagrams show using both. One shows bypassing the old terminal block resister and just using a junction block with the new resistor in line to the coil. The last one i looked at shows now using any resitor at all.

Bear in mind that its a top mount 12V coil that does not have a biult in resitor to my knowledge. I remember the old chevys had the resistor mounted up on the firewall as the new alternators had not yet integrated them in. Not sure how to proceed.
 
Welcome to the forum.
With the front mount distributor you should use the original
ballast resistor on the back of the dash with either coil.
If using a 12V coil that's all you need.
For a 6V coil you add another resistor in series.
The value of that second resistor depends on the resistance of the coil.
Google "wiring diagrams by JMOR" for a correct diagram.
 

Sorry Royce. Im confused on your answer where you said if its a 12V coil, thats all i need. It is a 12 volt coil. On a front mount distributor. By saying thats all i need, are you saying i dont need any resistor? or just the new one and bypass the old one?
 

The original on the dash is burnt out. Do hav the new one. Was going to replace the original with just a terminal block with no resistor in it.
 

Hi Bruce. I saw tip 30. Still Leary of my voltage test. I tested voltage at the end of the OEM resister and it was 5.8 volts. Was then useing the 6 volt coil. Now, at 5.8 volts, is that going to be sufficient juice for the new 12V coil?
 
The original ballast resistor on the back of the dash should be
used on a front mount. That resistor is all you need with a 12V coil.

That original resistor has almost no resistance when cold so
you have full power to the coil for start up. Then as current
flows and it gets hot the resistance goes up limiting coil current
so the coil/points, etc do not get damaged.

White ceramic block resistors are normally a fixed resistance.
Will it work with just a ceramic white resistor?
If the resistor is the correct resistance value, absolutely.
Will the components last as long?
I guess that would depend on the resistance value too but probably
not if it's too low. Too high of a value would cause hard starting.
 

Thanks Royse. Thats a fantastic explanation i can digest! ok then. The old one on the firewall saw its better day and rotted out. So, i will order a new one and go with it.
 

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