I'm interested in purchasing a "spark plug tester" device and in reading about them, I noticed that there are specific units that are designated for HEI ignitions. The application I'm currently working with is HEI, is there really a different between an HEI unit and Standard unit? Are there any recommended brand units I should consider purchasing? Thanks in advance!
If the tool you are looking at uses the ignition system for a power source then yes electronic ignition would use a different tool than contact points. Spark plug testing is sort of a thing of the past, back when every shop in town had a spark plug cleaner and plugs got reused instead of replaced they got tested. Champion makes a good tool, I don't doubt that snap-on does as well.
used to be a spark plug tester was just a neon lamp (NE-2) in a tube, resembling a ball point pen. you would hold it parallel to the plug wire, and if it lit up, that means the plug is firing. If not, the plug is fouled. It works off the electric field around a wire that's carrying high voltage, if there is a field, it means the plug is letting voltage build up and then spark, like it should. This type tester doesn't care what you have making the coil switch on and off. Points, HEI, whatever, it all works the same. There's also a spark tester for HEI, which is a spark plug with the ground electrode cut off, and a clip lead to connect the housing to ground. I use this type of tester (a home made one) to see if an HEI system is making a spark, or not. You gotta know more than the guy selling you the tool
LOL I thought he was talking about that little box that you stuck the plug in to test it. When I first started tuning at the local service station the garage had one. I asked the guy how to use it and he said, we haven't used in in years, if you tune one you change the plugs. So I asked what it was for and he said, well its paid for and it looks important. It was a Champion unit. I'll look around and see if I can find a pic of one. Here's one:
My apologies, I should have used the term/phrase "Spark Tester", to test if the distributor was passing spark to the plugs!
I always just used a screw driver stuck in the end of the plug wire. I do have an ancient test light though.
We used one in the '60s at Karl Stoll's place. Tune ups on VWs began to 'sour' after valve adj., dist. repair, and plug change. (we had 2 young mechanics performing standard practices such as these) I pulled a couple of wires, discovered plugs weren't firing...Put the Champion L87Y in the machine, cranked up air pressure and voltage. The little mirror under the plug showed it to be firing, but way up inside the plug body, alongside the insulator! In days to follow, found more than a few right out of the box with this problem. Karl had a 'deal' with the parts house, so was dismayed when I wouldn't use the Champions any more. I found him a deal on Bosch with the large "Worldwide German Parts" company. They actually delivered, 2 times a week! ('64 VW squareback: just like clockwork. German clockwork. (werk?)
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