ludwig113 Posted May 20, 2021 Report Share Posted May 20, 2021 Hi all, At some point i will be changing all the wiring on my 72 gt6. This means that i can go WITH or WITHOUT the ballast resistor, i am leaning towards no resistor... Any opinions? Link to comment Share on other sites More sharing options...
Mathew Posted May 20, 2021 Report Share Posted May 20, 2021 6 volt coil or 12 volt coil? Your answer may be closer than you think Link to comment Share on other sites More sharing options...
johny Posted May 20, 2021 Report Share Posted May 20, 2021 I wonder if theres any way to deactivate the starting 12v supply to see how your car starts with just the running voltage? If ok, and I suspect it will be unless youre car is poorly mainained, kept outside and started in severe winter conditions, then it should operate satisfactorily with a conventional 12v coil... Looking at the wiring diagram for the test I think it might be as easy as temporarily disconnecting the white/yellow wire from the starter solenoid. Strangely in my manual GT6 after KE20000 show the coil as always being fed through the resistor regardless of starting or running - this must be an error as otherwise theres no point having the system! Link to comment Share on other sites More sharing options...
PeteH Posted May 20, 2021 Report Share Posted May 20, 2021 The whole point, of having ballast resistance is to maximize the available voltage for the coil, when the cranking has reduced this voltage to a very low figure. Often the resistance is the actual wire itself, something much favoured by Ford at one period. Pete Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 20, 2021 Report Share Posted May 20, 2021 1 minute ago, PeteH said: The whole point, of having ballast resistance is to maximize the available voltage for the coil, when the cranking has reduced this voltage to a very low figure. Often the resistance is the actual wire itself, something much favoured by Ford at one period. Pete Hi Pete, Does resistance not reduce voltage? I would fit a 12v coil; easier to add aftermarket "ignition Modules". 2 Link to comment Share on other sites More sharing options...
Pete Lewis Posted May 20, 2021 Report Share Posted May 20, 2021 the ballast system is to help starts on cold days when the battery is not at its best the wire from the solenoid jumps the resistive feed and gives a 6v 1.5ohm coil a shot of 12v when cranking if you decide to go 12v only and delete the resistive wire you need to fit a 3 ohm coil running a ballast 1.5ohm coil on 12v you double the amps and double the HT this in turn will burn points and the high HT will cook rotors and caps also known to fry electronic units Pete 1 2 Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 20, 2021 Report Share Posted May 20, 2021 A 6V coil on a Six where you could give it 12 at high RPM's would bring back the lost energy? Link to comment Share on other sites More sharing options...
johny Posted May 21, 2021 Report Share Posted May 21, 2021 11 hours ago, SpitFire6 said: I would fit a 12v coil; easier to add aftermarket "ignition Modules". With a 6v coil I think it only means finding an ignition switch fed 12v supply to power the module rather than, as usual, use the supply to the coil which when running will only be ~6v. And sorry dont understand your next post! Link to comment Share on other sites More sharing options...
PeteH Posted May 21, 2021 Report Share Posted May 21, 2021 Ohm`s Law:- R(esistance) = Volts(V)/Current(I). Transpose:- I = V/R. Then, 12/1.5 = 8Amps :: 12/3 = 4 Amps :: 6/1.5 = 4Amps. Feeding the 6V, 1.5 Ohm Coil at 12V would virtually double the H-T and burn out over time. However when fed the voltage, as dropped during cranking, which can be as low as 9-10V, for just that short period it produces an enhanced spark but only during startup. During the running phase, The Resistance feed (ballast resister) reduces the 12V to circa 6V at all other times. Which IMV, is the point Pete was making before. Please accept my apologies if this is "granny sucks eggs" to many. But was how it was spelt out to me back when I was the "recipient" of this information!.! Pete Link to comment Share on other sites More sharing options...
Colin Lindsay Posted May 21, 2021 Report Share Posted May 21, 2021 2 hours ago, PeteH said: Please accept my apologies if this is "granny sucks eggs" to many. But was how it was spelt out to me back when I was the "recipient" of this information!.! Pete I've never had a ballast system so only read up on it recently due to a car I was working on, which has been quite crudely converted back to non-ballast. Am I right if I stated it as a 12v system where only the ignition part of the system is reduced to 6v in order to be able to boost it to the full 12 during starting, and only during starting? However the rest of the system must be permanent 12v for headlamps etc. I've heard it claimed in the past that the entire car runs at 6v, as in some early VWs, so there is a lot of confusion out there. Link to comment Share on other sites More sharing options...
ludwig113 Posted May 21, 2021 Author Report Share Posted May 21, 2021 thanks to everyone. i'll probably go without the ballast resistor, i'm not worried about cold starting. new wiring means new everything else as well so i can build the system from scratch. cheers paul Link to comment Share on other sites More sharing options...
dougbgt6 Posted May 21, 2021 Report Share Posted May 21, 2021 The ballasted system was designed in an era when winters were colder and batteries not what they are now, If I was starting from scratch I would bypass the ballast resistor/wire and get a 12 volt coil. Unfortunately I've an electronic ignition specifically for the ballasted system which cost me £100, so I'm not changing. Doug 1 Link to comment Share on other sites More sharing options...
Gully Posted May 21, 2021 Report Share Posted May 21, 2021 4 hours ago, Colin Lindsay said: Am I right if I stated it as a 12v system where only the ignition part of the system is reduced to 6v in order to be able to boost it to the full 12 during starting, and only during starting? However the rest of the system must be permanent 12v for headlamps etc. Correct. Gully 1 Link to comment Share on other sites More sharing options...
PeteH Posted May 21, 2021 Report Share Posted May 21, 2021 3 hours ago, dougbgt6 said: The ballasted system was designed in an era when winters were colder and batteries not what they are now, 3 Yorkshire-men?. 🤣. When we had sump heaters, Starting Handles, and often needed a push start!. Or if lucky. you parked facing downhill with wheels turned into the kerb?.👍 Pete Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 21, 2021 Report Share Posted May 21, 2021 5 hours ago, dougbgt6 said: The ballasted system was designed in an era when winters were colder and batteries not what they are now, If I was starting from scratch I would bypass the ballast resistor/wire and get a 12 volt coil. Unfortunately I've an electronic ignition specifically for the ballasted system which cost me £100, so I'm not changing. Doug And when people used 20W50. Another nail. 1 Link to comment Share on other sites More sharing options...
SpitFire6 Posted May 22, 2021 Report Share Posted May 22, 2021 If you have any type of points or other triggering technology. solid-state device. If its a cheap switching thing. Points will be higher powered when set correct. Those fit under the cap things are normally low powered. Some are variable dwell & allow a low ohm coil. Good low ohm coils are normally square shaped and laminated. Ballast wires/resistors waste energy. Go Green. Etc Link to comment Share on other sites More sharing options...
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