Master Shutoff Switch

[MJinCO]

I'm bit embarrassed to start another of my odd threads, but they might keep couple of you amused. My master shutoff switch doesn't work. It is a two pole switch on the negative side of the battery and does not shut off the ignition. The alternator is a motorcycle AC type with rectifier. I believe the mod I need to make is to put a relay in the positive lead to the coils and use the negative shut off switch to activate it. I have no idea when in the history of the car it was assembled this way, but it obviously is time to correct it.

My object for this year was to get the car running after its long sleep and see if I liked driving it. I do, it is a great fun. Now I have a laundry list of things to correct which if I wrote them all down people would just be shaking their head.

[kea]

Use the Switch made for applications where an alternator is in use and follow the directions. Your engine stays running from a possible back-feed.

[10rmotor]

I don't know what type of MC your alternator and rectifier are from, but on my suzuki and kawasaki powered cars, the rectifier output can be connected directly to the battery and doesn't need to be cutoff when the engine is not running. It won't discharge the battery. That way, your cutoff switch can be between the battery positive, and everything that needs 12V such as your ignition, oil light/brake light fuel pump and gauges. Note that while many will insist that the starter motor current also go through a master switch, the GCR does not specifically state that it is supposed to. I have a separate starter solenoid inches away from the battery thus only a very short cable is needed that is always "hot". This configuration allows you to use any type of switch at the rollbar you want. The lucas/hella type of master cutoff switch are garbage imo and have been the culprit of many electrical gremlins. I use a breaker type aircraft toggle switch like the potter brumfield W31 series available at aircraft spruce and co. Depending on what electrical components you're running, a 20 amp breaker switch is sufficient.