Re: Dial back timing light and curve question
First off, what exactly do you have for a distributor and type of advance?
If you have a distributor that has NO mechanical, and/or vacuum advance, then, YES, the dial back feature will give you accurate settings reports on dial back.
If you have an analog system, with functional mechanical and/or vacuum advance, then, NO, THE DIAL BACK FEATURE IS NOT ACCURATE TO READ TIMING.
Now, I KNOW there will be people on here that dispute that last statement above, but, I ask them to point out just where the "computer lag" is that a dial back feature compensates for when reading timing, please.
Here's a clue, EFI computers use inputs, throttle position, EGR, and the rest of the sensor inputs to literally compute just when to make the next spark event, ANALOG SYSTEMS, the ones NOT locked out, that still use mechanical and/or vacuum advance. DO NOT HAVE A COMPUTER LAG TIME TO COMPENSATE FOR, NONE, ZIP, NADA, NOPE, NYET, they read a straight on, non-processed spark event.
Now, it is a very simple thing to take a piece of chalk, set the dampener to 10 degrees, and make a new line at TDC, and do it again, 3 more times, that gives you a TDC line, plus 10, 20, 30, 40 50 degrees to read, WITH THE DIAL BACK FEATURE OFF, OFF, OFF......OFF. Reading the lines is dirt simple, 2nd line reads at 6 degrees, timing is 26 degrees, 4th line at 2, 42. Even the Geico caveman can do it.
There is no dial back feature that when in operation, reads an analog system properly, NONE, PERIOD. Is it worthwhile to have a timing light with a dial back feature, YES, if you ever go to electronic timing, it will be a benefit, but if not, leave it off, and read the antique timing curves right, with the dial back OFF.