Originally Posted by
JFB Tech
Not sure if they did it on the MkII Escort but a lot of Fords ran a 7 Volt coil fed through a resistance wire to drop the Voltage down. When cranking, they were fed with 12 Volts to boost the spark. If they run 12 Volts all the time then the coil will overheat. Would be worth seeing if the coil feed wire has been replaced with standard wire.
This is worth a check, this is known as "Ballast" ignition.
Yes a bad earth engine earth would cause it to heat up and cause problems elsewhere as well.
Martin