Minimum should be the factory's 6 degrees BTDC, max can me whatever the motor will stand with pump gas and a stock cam. Up to 12-14 degrees is typical.
I was wondering the same question on my 289. It has a 4100 Autolite on it. I am wondering what is the reference and where you see the degree marks on the engine case?
I see a little nub sticking out with a line on the top. Is that TDC or does that have nothing to do with the timing?
So the scale is on the harmonic balancer? (that's what the belt pulley bolts to right?)
I had my timing light on it last night and it looked like there was a white line on the HB. I wonder if someone just made a grease pencil mark on the HB. I was thinking I had to match that white line up with some numbers on the case.
I'll look at it again tonight to see if there is any kind of scale stamped into the HB. I'm sure there is if you say there should be.
Got the wire brush out and after a few brush strokes the harmonic balancer started to shine and low and behold some lines and numbers showed up.
Now, when I go to set the timing, I thought I read somewhere that a person should undo the vaccuum line for the advance and plug the line with a golf tee and set it like that. Guess that makes sense since the advance changes the timing...
Got the wire brush out and after a few brush strokes the harmonic balancer started to shine and low and behold some lines and numbers showed up.
Now, when I go to set the timing, I thought I read somewhere that a person should undo the vaccuum line for the advance and plug the line with a golf tee and set it like that. Guess that makes sense since the advance changes the timing...
You got it, although the timing will change little if any at idle. Once you have it set, plug it back in and rev it up watching the advance to see if the vac advance is actually working.
Now that I got my vaccuum leak solved my timing is much more consistant.
When I check it at idle with the vac advance disconnected and a golf tee in the vaccuum line I am sitting at 6 degrees, When I re-connect the advance I idle at 12 degrees and when I rev the engine up I am go up and over 36 degrees. So my advance is working, but is that excessive advance or is that pretty normal?
From what I've heard ( never checked total myself on any of my motors) total should be no more than about 38 degrees. If it's pinging at any time, it's time to either back off on the timing, use a higher octane gas or richen the mixture ( too lean)