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914World.com _ 914World Garage _ Who is running a Crane XR700

Posted by: Teknon Dec 26 2005, 12:58 PM

I picked up a Crane optical triggering system and the instructions talk of of a ballast used in some cases. Has anyone had to get a ballast for it? I have the trigger installed in a 2.0 dizzy and was wondering also if it can go in a 1.7. What would be the difference??

Posted by: SLITS Dec 26 2005, 01:21 PM

I have run them for years..........race and street

Ballast....only if the coil does not have internal ballast....bosch blue is internally ballasted (resistor to drop voltage to the coil from 12V to 9V).

There is no difference between the 1.7 & 2.0 dizzys other than the advance curve.

Posted by: Teknon Dec 26 2005, 01:36 PM

Thank you Ron, That helps alot. Joe

Posted by: SLITS Dec 26 2005, 01:42 PM

Oh, and if you don't drop the voltage to the coil...it will work...it will burn the center electrode and contacts in the cap, disintegrate the rotor and burn the electodes on the plugs real fast and overheat the coil....it will throw one hell of a spark to the plugs though..

It can also trigger the led and cause a misfire due to the intensity of the discharge in the cap..

Tired and true "Don't ask me how I know that"....

Posted by: Teknon Dec 26 2005, 04:01 PM

QUOTE (SLITS @ Dec 26 2005, 01:42 PM)
Oh, and if you don't drop the voltage to the coil...it will work...it will burn the center electrode and contacts in the cap, disintegrate the rotor and burn the electodes on the plugs real fast and overheat the coil....it will throw one hell of a spark to the plugs though..

It can also trigger the led and cause a misfire due to the intensity of the discharge in the cap..

Tired and true "Don't ask me how I know that"....

What do you mean..Drop the voltage to the coil??????

I may put a Jacobs Street-Pro on it after I get this to work.

Posted by: SLITS Dec 26 2005, 04:07 PM

The inline ballast resistor on many old cars, where the coil itself does not have a ballast resistor internally, is set up to feed the primary winding on a coil at 9V instead of 12V. The ballast resistor "drops" the 12V to 9V via resistance.

The coil you purchase should have instructions as to whether it requires a "ballast resistor" or not.

Posted by: Teknon Dec 26 2005, 04:15 PM

It is the Bosch Blue coil now, with the resistor (right). If I do nothing else that should work.

The Street-Pro with the Ultra-Coil has a trigger off the Bosch coil then it fires the Jacobs coil that feeds the dizzy. I check and see if a resistor is needed for the Jacobs.

Posted by: Dr. Roger Dec 26 2005, 04:21 PM

the 12V is needed for cold starting. after the engine warms up the ballast resistor heats up and voltage drops slowly to 9V which is plenty to run the coil but not too much to cook it.

roger

Posted by: SLITS Dec 26 2005, 04:21 PM

QUOTE (Teknon @ Dec 26 2005, 03:15 PM)
It is the Bosch Blue coil now, with the resistor (right). If I do nothing else that should work.

The Street-Pro with the Ultra-Coil has a trigger off the Bosch coil then it fires the Jacobs coil that feeds the dizzy. I check and see if a resistor is needed for the Jacobs.

Yes, blue is internally "resistored" and works fine...