A dial-back timing light is one that has an adjustable dial on the back - on the back at least on the ones I've seen.

You can set the dial for 36 degrees BTDC and when you spin the engine past the "all-in" point the timing light will show zero on the timing marks.

A nice feature for those who don't have a degreed dampener or timing tape installed.

Set the dial at zero and use like a regular timing light.


Looking from here, it looks like your timing light could be bad.

Keep in mind that at higher rpm levels the light will look like a solid beam of light, but it will show the timing marks at a standstill or floating around for a degree or two due to play in the timing chain.

Is there someone you could borrow a light from and see what happens?


One further thing, older timing lights are polarity conscious.

Little brother loaned some guys his old, but in nice shape timing light at the dragstrip.
They came back whining that the light didn't work.
They'd put the battery leads on backwards and burned it up.
It did flash, but not well and that was pretty much the end of that light.