Home Triumph TR7 projects Switch panel Julian Rogers Home

In my opinion, the original instruments are pretty cheap and nasty on the TR7. OK, the front perspex could be re-polished but there is no oil pressure, the clock is often broken and the voltmeter is nowhere accurate enough to diagnose all but the most obvious charging faults.

Also even with a change of resistor value (see How to Improve Triumph TR7 etc. by Roger Williams) I couldn’t get the rev counter to work with my Megajolt ignition system.

It’s possible to dismantle the instrument cluster, slightly enlarge the holes where the instruments went and fit two 100mm and four 50mm instruments.

I used ETB rev counter, speedo and clock and mechanical oil and water temperature gauges by TIM. I like mechanical gauges because I believe they are more reliable, work when the ignition is off (good for temp) and if they do fail they register zero which is easy to spot.

The downside is the capillary tube which in the case of the water temperature can’t be disconnected from the instrument so fitting is a pain. Also the TIM and ETB don’t quite match in style if you look carefully.

If the gauges are poor, the switches are awful! I know the look is a matter or opinion but the operational feel is poor, they are dirt traps and the works at the back are unprotected and open to contamination. The random blanking plates are horrible as well (IMO).

I replaced the switches with Lucas-style toggle switches which, I suppose, are sixties style and out of period for the TR7. Nevertheless, these are what I have used! The switches available are probably made in China and don’t quite have the best feel and positive action but that’s what is available at a reasonable price. I don’t trust them to carry anything over about an amp without a significant voltage drop after a bit with accompanying overheating and eventual failure. So they need to be backed up with a relay or mosfet. Also only a limited range of contact configurations are available (SPST, SPDT, DPST, DPDT) so complications may arise for, say, a hazard circuit.

Details of modifications to the main switch panel come next.

Instruments & switches