How do I connect a dwell meter

[rd100]

I've got a '74ish Maxi-tun dwell/tach/volt meter from RAC. No manual.

It's got red and black alligator clips. It also has this other wire that ends with a red and black connected to this small bar with a twist knob screw on one end.

I put the red alligator clip to the positive of the coil and the black alligator clip to the negative of the coil and I seem to be getting dwell readings, and the "points" ok/bad readings along with Tach.

However the tach seems to read higher but I'm not sure if I need to divide by 8 for my 302 or how this works. There's a slider switch for 4/8 and 6 cylinder. There's also a low rpm and high rpm setting on the dial which just seems to double the tach reading for high/low.

How do I zero the needle. I know where the adjustment knob is, I just don't know how you calibrate it. Can I use the volt function across the battery and adjust the needle to what I compare the volt value using another multimeter?

I'm getting a dwell reading of about 22 degrees and I'm supposed to be getting 24-29 according to the book.

Thanks for the help guys.

[ToughOldFord]

I've got a '74ish Maxi-tun dwell/tach/volt meter from RAC. No manual.

It's got red and black alligator clips.

It also has this other wire that ends with a red and black connected to this small bar with a twist knob screw on one end.

That sounds like an amp shunt, you will not need that for RPM/Dwell.

I put the red alligator clip to the positive of the coil and the black alligator clip to the negative of the coil and I seem to be getting dwell readings, and the "points" ok/bad readings along with Tach.

There's your problem, black gos to body or engine ground. Red goes to the negative terminal on the coil. Same way you hook up an aftermarket tach.

However the tach seems to read higher but I'm not sure if I need to divide by 8 for my 302 or how this works. There's a slider switch for 4/8 and 6 cylinder. There's also a low rpm and high rpm setting on the dial which just seems to double the tach reading for high/low.

No, the 8cyl readings will be accurate. Some of the old meters you had to double the readings for the 4 cyls.
High RPMs is what it says. Low RPMS is for idle adjustments only. It allows a finer tuning and helps in diagnosis.

How do I zero the needle. I know where the adjustment knob is, I just don't know how you calibrate it.

If the meter's accurate then just disconnect it from the engine so it's 'off' then adjust needle to zero.

Can I use the volt function across the battery and adjust the needle to what I compare the volt value using another multimeter?

You could do that, if it is necessary to do so I'd question the accuracy of the entire meter.

I'm getting a dwell reading of about 22 degrees and I'm supposed to be getting 24-29 according to the book.

Assuming you are still running point, (sounds like it from that reading), too little dwell = too large a point gap, to much dwell = to small a point gap.

Thanks for the help guys.