None of my digital meters have probe tips that are long enough reach the terminal at the bottom of a spark plug barrel, so I whipped up this little adapter for checking plug resistance.
It's just a scrap of delrin, a screw, and a spring. Some quick and dirty work with the lathe, then the screw is threaded through the plastic and the spring is threaded onto the protruding screw threads inside. If you don't have a lathe, you could probably make something similar using a properly-sized plastic spacer from the hardware store parts bin.
To use, I clip one lead of my meter to the screw, stick the adapter into the barrel, and touch the other lead to the center electrode.
It's just a scrap of delrin, a screw, and a spring. Some quick and dirty work with the lathe, then the screw is threaded through the plastic and the spring is threaded onto the protruding screw threads inside. If you don't have a lathe, you could probably make something similar using a properly-sized plastic spacer from the hardware store parts bin.
To use, I clip one lead of my meter to the screw, stick the adapter into the barrel, and touch the other lead to the center electrode.
