Ballast resistor wire

[sonscar]

Following a points failure I am looking to upgrade the ignition system.I want a 12V feed to the coil instead of the present ballasted system.Does anyone know where the present ballast wire starts so I can disconnect it?If not I will search for it as I suppose it may be under the dash somewhere and I would rather not remove it again if it can be avoided.Thanks Steve..

[sonscar]

After using search again found its whereabouts from a 2008 post,will go and look for it and remove and bypass it.Steve..(searched under ballast and was lost,searched under eureka after consulting manual and was found)

[saabfast]

It would be better to upgrade to Elecronic ignition. I fitted the Pertronix/Aldon Ignitor unit in my distributor a few years ago and have not touched it since. Starts, idles and runs better and no points to keep adjusting/changing. I got it from Retro Rockets in the US (but delivered from a UK warehouse) as the cheapest supplier. There are cheaper systems around now but I think you have to remove and strip the distributor which is not necessary with the Ignitor set up. It can be fitted in less than an hour.

Alan
Saab 9000 Stg 1 (now passed to son for his family car)
Saab 9000 2.3 FPT Auto (now gone that others might live)
Saab 9000 2.3 LPT Auto (sold on, wish I had it back)
Saab 9-5 2.3 Vector Auto Estate
'81 TR7 DHC

[sonscar]

Fitted electronic ignition on son's classic Mini which also has ballast ignition.I suspect Tr7 wiring is the same quality as Mini wiring,and the tales of the ballast wire ageing,overheating and burning the loom are legendary.The electronic ignition needed a 12v supply so for simplicity I fitted a 12v coil and removed the ballast wire.I intend to do this with the TR7.Steve..

[HDRider]

Early cars have a resisitance wire incorperated into the wire loom under the dashboard.

Edward Hamer
Petaluma CA

[sonscar]

One end of it is joined to the wire going to the coil near the fusebox,any idea of where the other end is?Thanks Steve..

[bmcecosse]

The ballast system works REALLY WELL on the TR7 (and on the Mini) - stick with it! It really does help cold weather starting.

[Stag76]

A 12V coil needs 12V to work properly, and there is only approx. 8-9V available when the starter is turning. The feed from the solenoid supplies this 8-9v to the coil when starting, then the Ballast Resistor reduces the 12v to 9v when the starter stops and the engine is running, keeping the 9v coil supply at the correct voltage.
As bmcecosse says, a 12v coil may not help cold starting, as it's only getting 8-9v.

TR7 Convertible
Sprint Motor
MegaSquirt EFI

[sonscar]

I run an MGB and An Austin Healey both with 12V ignition systems and never have experienced any starting problems however cold it has been.I am going to remove this wire and fit a 12v coil,and live with the consequences.If all else fails I can always fit a resistor or reconnect the wire.Steve..

[HDRider]

Actually all coils are 6 volt. It just a matter of wheather they are internally ballasted or externally so.

If you run a coil that is designed for external ballasting without any ballast it will just burn out fairly quickly.

Edward Hamer
Petaluma CA