Dwell/Tach meter question

[Jeff Ivan]

I have always set the points on my Plymouth using a feeler gauge. I have a 1970's era dwell meter that was my dad's, but I always just thought it was for 12 V neg. ground only because that is what we were using it for back then and I know the best way is with a dwell meter. So reading on this forum here recently I saw postings about dwell meters and a dim 6 volt bulb lit up in my head. So today I got mine out and printed on the side of the box where I never looked it says 6, 12, & 24 volt systems, positive and negative ground. And also Wankel engines - are those still around??!! My original Plymouth shop manual has the specs for the dwell angle, but does not say or show how to hook it up, any idiot in 1951 should have known that! The last time I used this meter was over 15 years ago on one of my 1970's Power Wagons with electronic ignition to set the idle speed. I remember for that the red wire on the meter hooked to the -neg terminal on the coil and the other black wire to ground. What about +pos ground? Here is my confusion now, is the red meter wire when hooked up to a +pos ground car hooked up to +pos on coil? Or do I just reverse the leads and hook up the black meter wire to the -neg terminal on coil? Or is it hooked up the same way? I know this is probably an obvious answer, but electrics ain't my specialty and I would really hate to fry this meter. The photo is a little blurry, but see the pic of the 1968 Chevelle on the box. Thanks, =Jeff=

[Don Coatney]

Jeff;

I connected my dwell meter as pictured for bench testing using a 6 volt negative ground power supply. Red to the distributor lead and black to ground. If you connect your meter this way and it does not work with a 6 volt positive ground system simply reverse the leads. Black to the distributor lead and red to ground.

[Lou Earle]

I have the same meter

Hook the positive side to the battery pos or somewhere on the block/engine attach the neg to the POS-YesPOs side of coil leading to the distributor. Remember the neg side of coil is attached to the ignition switch.Mine works great that way

lou

[Jeff Ivan]

Don & Lou- Thanks for the helpful info. Sounds logical, I have very little logic when it involve some of these electrical situations. Thanks again,Jeff