jjbunn said:
Now, what I don't understand is what the connector should look like. The HV socket on the Lucas coil is threaded.
I'm pretty sure that makes it the wrong coil. The TR2-4 used that kind of coil (with the nut), but I believe even the TR250 had the 'modern' push-in connector.
For the coils with the nut, the nut is supposed to be slid over the (stripped-back) wire, then the protruding copper end goes through a washer and gets soldered to the washer. Then when installed into the coil, the nut clamps the washer against the terminal inside the coil tower. Trying to use a push-in coil wire with this coil is a Bad Thing, as there is simply no metal inside the coil tower for the clip to mate with. You wind up with the spark having to jump the gap between the end of the clip and the coil terminal, which will eventually erode the clip and cause strange ignition problems.
Sorry I don't have a photo handy, but here's a drawing from the Moss catalog.
PS, my advice is to sell the coil to some TRactor motor originality freak and buy one with the push-in connector. But be warned that there is an early and late TR6 coil, and you most likely want the early one unless there have been other modifications like electronic ignition or a ballast resistor added.
Randall