The Stovebolt Site Forums The Shop Area The Electrical Bay Bench test HEI distributor

Been reading up on different things a guy can do to test indivual components of a GM style HEI dizzy. Coil and module…easy enough and I will do that.

Any reason I couldn’t rig up a way to spin it, connect wires as appropriate to battery as appropriate, maybe wire in my little spark tester….and see if the whole thing functions as a system?

I don’t see why that wouldn’t work?

In your research, does it recommend having a spark plug at each termination? You'll have to ground them all and back to the battery negative along with the body of the distributor.

Just take the top cover off the coil and connect 12V to the terminal that's hot with the ignition switch in the "run" position. Ground the battery to the housing. Spin the shaft, and sparks will jump to the laminated coil core. No wires or spark plugs needed. I use a cordless drill motor with a sanding cartridge roll pressed against the bottom of the drive gear to spin the shaft, with the distributor housing clamped into a vise. That 1/2" spark that jumps from the plug wire towers to the coil core is a little over 50K volts- - - - -don't get your fingers close to it!
Jerry

I put the distributor in a vise.
I remove the distributor cap/coil and attach a twelve volt wire to the distributor cap which feeds the coil and attach the battery ground to the aluminum base of the distributor.
I wrap a piece of thin wire around the lower housing tube.
I arrange for the end of that wire to be a half inch from the contact of the rotor.
I then turn the distributor gear by hand and become amazed by the lightning which snaps 1/2" between that wire and the contact of the rotor every time it passes the wire.

Leave the cap on the distributor, and you'll see that same spark at every terminal. I used to use an old Sun distributor tester as a drive unit, and spin up a HEI distributor in it, then put one plug wire on it and hold the spark plug in my hand, being careful NOT to touch the machine. The plug would fire every time the rotor came to that terminal- - - - -it gave me a little tingle, but the students were amazed that I could hold onto it! The other seven terminals would fire a long spark back to the coil laminations.
Jerry