Although I would very much appreciate having the convenience of an additional pump during a failure, I have found the reliability of an SU points-triggered pump to be outstanding…especially with the very inexpensive TSV modification discussed previously. To further this exercise, I and 2 friends (and MGB owners) from Calgary, designed and built a fully optical triggering circuit as a plug-in conversion for the SU points-based Pump. This circuit has very good electrical protection (apposed to the problems experienced with the SU transistorized trigger) and, although the PCB will fit inside the original cover and should extend pump life indefinitely (dependent upon the diaphragm), it was disappointing that the loveable tick was lost (no touching moving parts).
I believe the SU pump is quite reliable and, for many years, have stored a separate pump in the boot (diaphragm/solenoid/trigger) to exchange in case of a failure. By not exchanging the full pump, I found I can eliminate the concern and potentially struggling to align and possibly cross strip the body and gas lines during replacement. By jacking, removing the wheel, removing the 7 screws and changing wiring connections, a changover represents a 10 minute job on a BJ8.
However, although I still think mounting a second pump is overkill, I would have appreciated the extra installed pump during a trip a number of years ago. On that trip I had not yet installed the TSV on my installed points-based pump and it had been installed for abut 30 years without failure. Pulling over and determining the problem was the pump, I tried to jack up the car and my original jack simply sank into the ground. Although I still depend upon the spare in the trunk as my saving pump, I also carry a small board under the spare to place under the jack …just in case.
Sorry, as I know this was not what you were looking for but I suggest that if you install, or even carry, all the additional parts that could fail your Healey would be twice its weight.
All the best,
Ray (64BJ8P1)