Triumph Repair: no spark, spitfire 1500, starter solenoid

Question
I bought a 1979 Spitfire 1500 that I was told ran when it was parked several years ago.  I've been trying to get a spark to the spark plugs but without any success.  I have replaced the Coil with a Lucas DLB4102 and replaced the current electronic upgrade with a Petronix electronic ignition #222-425 from Moss Motors.  I have disconnected my lead from the coil trying to get a spark to ground... nothing... I have voltage at the coil of about 4.8VDC... I'm needing some help with my frustration here...

Answer
When the ignition is on, you should have full voltage at the coil, +12.  You should be able to twist the distributor when ignition is on, and set your static timing by getting the coil to fire.

First step would be tracing why you only get 4.8V.  Usually the +12 ignition come directly off the starter solenoid to the + side of the coil.  

Go through a wiring diagram for your year (see some of my other posts for links) and trace your +12.  As long as you are running a +12v coil, you should be able to jumper +12 from the battery directly to the coil to get a static timing spark.  Also make sure your ignition box/amplifier is well grounded, if it is an external to the distributor unit.  I helped a friend this past weekend, similar issue, no spark, but +12 at the coil, and the problem was his ignition box wasn't grounded.  Made a ground wire, got spark..

Good luck.