123 ignition

[Charles Farran]

In reality, when running ,the voltage at the coil on ballasted systems is i believe (from earlier discussions) about 9 volts given the constant breaking of the LT circuit when the points open & close.
Charles

[Stephen Aitken]

Hi
Wiring is connected up fine with power from fuse box. I can connect fine to the app on my phone and is showing green ‘connected’ note the ignition disabler is switched off). I’ve also added in a curve.
I’ve recently ordered a replacement cap and a flame thrower coil. After speaking with the supplier they said that other customers had an issue with the blue Bosch coil (which I have) (12v) ‘interfering’ with the 123 - doing a little googling reveals some indeed have. I’ve now got the parts delivered today so will fit tomorrow and see what happens..

[Paul Hollingworth]

My friends 68 B had had a ballasted ignition system fitted to it. I removed the resistor, wire down to the starter motor and fitted a new Bosch blue coil (as recommended by 123)

[Stephen Aitken]

Hi Paul
When you say removed the resistor wire to the starter which wire was it?

[Dave Wheatley]

Have a look at this thread Stephen.
viewtopic.php?f=4&t=863
A lot of usefull stuff there. A few other threads on ballasted ignition too!

[Stephen Aitken]

Hi
Just to note problem solved. In the end 123 wiring was all good but it turned out that one of the plugs had turned bad. Despite removing them, cleaning and regapping I hadn’t checked their performance (they were also relatively new) - had bought replacements and she started straight up no issues..
Thanks to all who responded.
S

[Paul Hollingworth]

The resistor is in series with the coil so drops the voltage the coil sees to a nominal 6V. When cranking 12V is fed from the starter motor so in effect you are running a 6V coil at 12 V which is supposed to give a better spark. I think it just ensures a good spark if your battery is on the flat side.

[Vic Butler]

That's correct. It's switched by relays and the 12v comes from a separate contact on the starter motor. It's a complex set up which has been discussed in depth on the forum. The resistor on rubber bumper B's is a length of resistive wire in the loom.