The Stovebolt Site Forums The Shop Area The Electrical Bay Security switch question/idea.

There’s a question at the end of this.

There are dozens of ways to deter theft of a classic vehicle.
Each security measure has its own pros and cons.

Here’s the idea I like best. Simple and subtle.
Hide a switch inside (under) the leather boot of the floor shifter handle. You flip the toggle switch by feeling it through the leather boot. Thieves could look all over the cab and under the hood and not find the switch because it’s not visible to the eye.

The closed switch connects the negative side of the coil to ground, thus preventing the engine from running. Open the switch and things work normally. The single wire and switch are easy to hide and cheap.

My question: Could this “security wire system” damage ignition parts (HEI, Pertronix, points, coil)?

I have ignition cutoff switches hidden under the dash of certain vehicles.

The starter circuit still works but the engine won't fire if someone tries to start the vehicle with or without a key. Hotwiring will just spin the starter. Thief will give up.

No guarantees on a Pertronix- - - - -those things go belly-up if "The moon is in the seventh house and Jupiter aligns with Mars"- - - -but an easy, no damage way to disable a HEI is to ground the "tach" terminal on the distributor cap. That used to be one of the diagnostic tricks I used on my students when I was judging high school skills competitions.
Jerry

Yes, my plan was to ground the tach wire with a switch. I wouldn’t need to lift the hood. I left the “tach wire” out of first post of this thread so readers would understand without thinking a tachometer was required. Of course grounding the tach wire accomplishes the same result.

A good winter project

An additional low/high beam headlight foot operated floor switch could also be wired as a dedicated security switch. The downside would be that you can’t tell if the switch is open or closed just by looking at it or feeling it.

If it is the good old floor shift truck 4 speed. Just remove the shift lever, and still have a hidden switch. With a 3 speed column shift a person could figure out a simple open the hood to install blocking system for that. Also a valve someplace in the fuel line could be done.
The more things done the more difficult the get in and drive away would be.

Heck, any manual gearbox now-a-days is a theft deterrent, youngin's and thieves can't drive 'em.

True story. Young girl was forced by 3 thugs at knife point to get back in her car, go to her bank and they told her they would rape her. They took her keys and soon realized the Honda car was lurching when they tried to start it because it had a MT. First guy bailed from the plan. Other 2 guys forced girl to drive them to an ATM and withdraw money. She undid her seat belt to use the ATM and only pretended to click it back in place. Then when she had a chance she bailed out of the car at a stop light and left the 2 thugs in the car. The manual transmission and her smart thinking saved her life.

When Ford first started selling fuel injected vehicles, they put an "impact switch" in the fuel pump circuit. The sudden stop of a wreck would trip the switch and disable the pump, preventing gasoline spillage from a broken fuel line during an accident. Pickup trucks and vans had the switch mounted above the transmission tunnel just below the dash, to the right of the gas pedal. A friend would kick the switch before leaving his truck parked and disable the fuel pump. Even if a thief hot wired the ignition, the engine wouldn't start- - - -no gas! Just a quick push on a plunger on top of the switch would reset it.
Jerry

Those F-150 switches are notorious for shutting off the fuel pump for no apparent reason (not while running, fortunately). Most people are unaware of the reset button.