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Greetings, Oh Sage Ones, it's a 1974 CF, running an Eaton supercharger, and an SU HD8 carburetor. Ignition is all Distributor Doctor, cap, leads, rotor, coil (ballast resistor type). I suspect the ballast wire. I snipped off the female spade connector on the two wires to the coil, and replaced it. As a result the misfits was greatly improved, but still there. Can anyone tell me if a better way of supplying the lower voltage (I assume six volts?) exists?

Many thanks, Austin

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I would go for a CDI ignition like MSD6 or ACCELL.

 

I have both in use on my two TR6 because ignition

ex works is at the limit and over the years it might

drop below the limit.

 

A first remedy can be to use spark plugs with no

resistance built in and with a smaller center electrode

like the iridium plugs. They also have a smaller gap like 0.6mm

 

If there is more pressure in the combustion chamber like

from a supercharger the spark "sees" a bigger resistance

and refuses to jump over from time to time.

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Hello Mike, please forgive my stupidity - I have never seen one of these on my car. My reading of the workshop manual led me to believe that the voltage was reduced by the use of a resistance wire. Where will I find this on my car? Or do I need to re-wire, by-passing the original wire, and using the ceramic ballast resistor?

Austin

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Hello Mike, please forgive my stupidity - I have never seen one of these on my car. My reading of the workshop manual led me to believe that the voltage was reduced by the use of a resistance wire. Where will I find this on my car? Or do I need to re-wire, by-passing the original wire, and using the ceramic ballast resistor?

Austin

Thats an aftermarket part as fitted to early series one Jaguar XJ6 and others of that era but not TR6 as they used a ballast wire in the loom.

Stuart

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I thought it was original- it was installed on my 1969 CP when I bought it 20 years ago and looked old then. It's often sold as a TR6 part.

 

Mine's mounted on the horizontal section of firewall behind the wiper bottle. I'd wire the ceramic resistor in place of the resistor wire.--so that 12V is fed direct to the coil when the starter is energised and once the engine starts and the key is released the coil feed reverts to feeding through the ballast resistor.

 

Without seeing your wiring , I'd guess I'd mount it in a suitable location and connect the ends of the ceramic resistor to the same points as the old ballast wire but using copper wire.

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  • 4 months later...

Austin, what boost are you running? I have the eaton/holley setup and am running 4psi.. For ignition I use a standard distributor running through an Aldon Amethyst (to allow me to use boost retard if I need it). Mines a CP so no ballast, but despite this starts better than any classic I have ever had (e.g. First turn of the starter).

tim

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