Triumph Repair: 1979 spit, ballast resistor, external resistor

Question
QUESTION: I recently bought a 1979 spitfire for my wife, and it does not get spark from the coil all of the time. When it does, it is faint orange. The car is all original, with exception to the coil(12v w/external resistor) and battery(12v). I am getting 8-9v at the + lead of the coil w/ the ignition on.  When it does start, it runs good, but will die w/o warning.  After a couple of tries, it starts back up. Can you help me before my wife sells the car?  Thank you, Jarod

ANSWER: Jarod,

The late Spitfires used a 6v coil and a ballast resistor in the wiring harness for running, with a direct connection from the starter solenoid to the coil to give a better "kick" on starting.

Have a friend try to start the car while you put a voltmeter on the coil terminal... you should see the 8-9v while it's cranking then it should drop to 6ish.  

It may be as simple as replacing the coil with the proper 6v unit.  Any of the vendors on listed on the VTR website (www.VTR.org) can supply the correct unit.


Cheers,

Jim

---------- FOLLOW-UP ----------

QUESTION: Thank you so much for the help.  The only other  problems that I have is the timing(currently at 13btc) is this correct. The car is a bear to start when it is cold, it has a water temperature controlled choke, can I adjust this for a colder start?  Thanks again, Jarod

Answer
Jarod,

It's possible to verify that all the mechanical parts in the choke assembly are clean and moving freely... but "tweaking" the choke doesn't work on the auto setups.  

Usually all you wind up doing is setting things so the choke won't open once you've reached running temp.

Basically the automatic choke setup uses a bi-metallic spring, similar to a regular household thermostat.  With age the spring...er.. loses it's spring.

There's a good set of instructions in the Bentley Manual for the late Spitfire (ISBN 0-8376-0122-3) that are unfornately a bit too involved to summarize here.

One thing you might consider is getting a mechanical choke Stomberg CD 150 from an earlier vintage 1500 (1973-1976ish) and fitting that instead.  That way YOU will be in control of the choke setting.


Cheers,

Jim