Timing Advance

The 009 distributor is timed at 7.5 degrees BTDC... The nice thing about the 009 is that it can be timed statically. BUT make SURE that both of the vacuum ports (on the carburetor) are plugged.

The 009 should be timed at 28-30 degrees at 3000 rpm. THEN you check the static timing, which might be 7.5 degrees BTDC. It can end up anywhere from 5-8 degrees BTDC, because the 009s vary in the total amount of advance they make, and the FULL advance is much more important than the idle advance. Once that particular 009 has been set at 3000 rpm and the idle timing established, the idle timing can be set static for that particular 009 (be it 5-7-8 degrees, BTDC etc). 7.5 degrees BTDC without checking max advance is only a rough starting point.

And the MAX advance depends mostly on compression ratio and the available fuel. If compression is high or fuel quality (high oxygenates) is low use 28. If compression is low or fuel quality is high enough use 30.

Short story - use 30 and try it. If it detonates, back it off to 28 and/or try another fuel.

With the single vacuum units, setting the (static) idle meant the vacuum decided how much advance was introduced, and when. These can top out at around 40 degrees under part load, but 40 degrees is way too much for full throttle high speed, where 30 is about right. So the 009 (which has varying amounts of internal advance) has to carefully limited to 30 max, so it will won't be over advanced in "worst case" conditions. This means it's not ideal in part load conditions of course, so not quite as economical as the vacuum units either. And once the 009 max timing has been established and the total amount of internal advance noted (checking the static timing) this static timing can then be used to set that particular 009.

So, -- to summarize -- set the advance timing with a stroboscopic timing light, 30 degrees BTDC at 3500 rpm. Then return to idle (800-900 rpm) and note the point on the pulley that crosses the crack in the crankcase when #1 fires. THAT is the idle timing point for that particular 009 distributor (be it 7.5 degrees BTDC or whatever) and from then on it can be timed statically to THAT point.

Exactly.

Regarding the 28-30 degrees at 3500 rpm: With that distributor working right, don't be surprised if you see about 40 degrees at 3500 rpm! The mechanical part will pull in about 30 degrees total, but the vacuum part adds 8-10 degrees under certain conditions (mostly higher revs at light loads) for more economy. The vacuum part then backs off if you plant your foot, so it doesn't become over advanced under load just the centrifugal part working then. Then as the revs increase further, the vacuum will gradually pull the extra advance in as needed.

Try running it with a little more or a little less max advance too (28 32) -- you might be able to tweek with just those modifications.

You're saying play with the timing at 3500 rpm to find the optimum point?

Yes. As much advance as you can without it pinging would be best I think (more advance = less hesitation). You might end up with an idle advance of 10 degrees BTDC or so, but that should not cause any problems.

In the meantime I'm going to jack the timing up a bit like you suggested in actuality it doesn't QUITE come up to the 30-degree mark when I rev it to 3500 rpm. And you say if it settles back to 10 degrees BTDC or so at idle, that's okay, right?

The idle is not nearly as important as the max advance. If it will take 32 degrees without pinging, and the idle comes to 11 or 12 degrees BTDC it doesn't matter much to the idle, but will help with the hesitation. In fact in your cold weather, it might even take 33 or 34 without pinging at full throttle, but if you do that, don't forget to reduce it a touch when the weather warms up again (detonation is a function of heat remember, so it's more likely in hot weather with an advanced ignition).

The 7.5-degree BTDC standard simply matches the vacuum distributor's maximum advance characteristics. Some of the early 1200s used 10 degrees BTDC anyway, to suit their particular distributor design.