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I want to install a rotary disconnect switch at the starter of my 41. I will need to fabricate a bracket to suspend the switch. Has anyone attempted this and has it worked satisfactory. Any suggestions that may be helpful would be greatly appreciated.

What many folks do with underseat batteries is mount the switch to the floorboard just ahead of the seat and between your legs so it's easily reached from the driver's position without having something underhood. Use it to break the ground cable. I've done this or had it done on perhaps a half-dozen 1941 Packards and believe it's the best approach. No bracket needed, just a hole in the floorboard.

Of course you could also use the switch to break the "hot" cable but there is a, granted remote, hazard with that should anything metallic like a wrench ever fall on the switch terminal an also touch the frame or body. Some who use the switch to cut the hot cable put it on the driver's side of the cowl, breaking the cable going to the starter motor. You'll need to very agile to reach under the dash each time you want to use the switch and, if it's location isn't very convenient, then there may be a tendency to not use it religiously - a habit you don't want to fall into.

Hi Owen

Just a bit more clarification is needed here for those of us who think of the battery positive pole as 'hot' and find the concept of positive ground contradictory.

"Use it to break the ground cable."

Does this mean the ground cable regardless of whether its attached the to positive or negative pole?

"...you could also use the switch to break the "hot" cable..."

Would a disconnect switch attached to the negative pole battery cable in a positive ground car would be considered "hot".

Dense here about electrical issues....and many others, for that matter....

Steve

I'm obviously dense too, too many years owning cars with negative/black being the ground. Good question, thank you both for replying to my question.

Best practice is to use the switch to break which ever cable goes to ground; the positive cable in a positive ground system, the negative cable in a negative ground system.

In the 6-volt era the majority of makes used positive ground; Ford, Chrysler, Packard, Hudson, Nash, and many others. GM tended to be the exception but even Cadillac and some other GM cars used positive ground at one time or another. So it's not really something uncommon for the era.

And one other thing on breaking the ground side is you want to have the insulated round ground cable as was typically used on pre 51 cars. Putting a switch in a braided type ground cable wouldn't work too well if the braid before the switch could accidentally be moved and touch metal -- but I have seen installs done interrupting the bare braid. If that is the option, at least get some sleeving or shrink tubing and place it over the portion of the braid before the switch.

This topic was discussed very recently under the thread below with suggestions and photos.

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?viewmode=flat&type=&topic_id=15770&forum=1

I saw a 41 110 Special Coupe with a rotary battery disconnect switch mounted on the top of the frame rail behind the steering column. It looked to use the regular starter cable from the battery to the switch and another shorter cable to connect the switch to the starter. Of course this disconnect was on the 'hot' or negative side. It was down and out of the way but easily reached.

I have battery disconnects on my two vintage cars (one Packard, one Hot Rod) parked in the attached garage. I use the disconnects on the ground side. They are used for safety purposes, trying to prevent electrical fires in the garage. They are not so much for security, as they can be easily seen.

(o{}o)