I just became an "Expert" last month when I was installing a Crane ignition in
my '79 Spit.
The XR700 ignition is designed to be run with a ballast resistor, according to
the Tech Line people at Crane. Their XR3000 ignition is designed to run at the
full 12V (no ballast).
Spitfires (at least my '79) dont have a ballast resistor. Instead they have a
resistance WIRE (pink/white) that runs from the starter solenoid to the
ignition switch (active when the key is in the ON position). This wire is
bypassed during START to provide the full 12V when cranking. During normal
running you should measure 7-9V at the + side of the coil. So don't put an
additional ballast resistor in, just 'cause you can't see one!
The Crane folks say that while running the XR700 on 12v (without the ballast
resistor) won't hurt it for a while, long term you need to use one (overheats
the transistors), or upgrade to the XR3000.
The Crane tech line is at 904-258-9055.
'79 Spitfire FM96062
'88 Lotus Esprit
'88 Mustang 5.0
> -- [ From: Chris Reilly * EMC.Ver #2.5.3 ] --
> I just purchased a Sport coil for my ''78 Spitfire and it indicates that
> I need no balast resistor for it. I currently have the Crane Xr-700
> ignition on my car. Can I just bypass the ballast resistor at it's
> connectors and take it out of the circuit ? Will this affect the Crane ?
> I have no docs on the Crane ...
> Any info appreciated