360 Questions.. pardon my ignorance.
It’s set at 1000rpm because it drops to 550-600 in gear (auto). In gear it idles fine and will pull itself along without issue until the tiniest part of throttle is applied where it stumbles a little. I guess I will start by backing off the initial timing and make sure it’s adjusted while idled down.
I knew you would bring that to the table, lol!
Lemmee explain.
With so much Idle-timing, your engine it is nearly impossible to bring the rpm down without completely closing off the Transfer slot which is your main fuel system. The mixture screws are just there to richen up the "curb-idle", which is your basic throttle opening.
The image that
@Oldmanmopar provided shows you almost exactly what your Transfer slot exposure should look like, if you take the carb off and flip it upside down. Personally, in your case, I would make it square. This method is not the easiest, but it is pretty accurate.
The method I detailed is easier and faster, once you understand what needs to be done, but perhaps not quite as accurate for a newbe.
Either method will get you into the ballpark.
The freedom from tip-in sag is what you want ...... together with an rpm drop from N>in gear of NOT more than 100>150 rpm. This can easily be achieved with the stock engine, assuming no vacuum leaks, and an accurate/stable fuel level. The trick is to keep the Transfer Slot from drying up, and the combination of fuel-level and exposure underneath the throttles is what controls most of that.
Let idle-timing be what it will be for now; whether 8* or TDC, just get rid of the Tip-in sag. Earlier I suggested a starting point of 6*, and Ima sticking to it.
I guess I will start by backing off the initial timing and make sure it’s adjusted while idled down.
Good decision.
That “OSAC” port is the one I’m using for the advance cannister.
I'm not sure that's the one you want. I think it comes in too early and quits too soon.
The one you want is in the vicinity of the front edge of the passenger side, closed throttle valve, outboard of the Transfer slot. It should be slightly ABOVE the valve at idle, and be progressively opened by the progressively opening throttle.
On the idling engine, in Neutral, the sparkport might not begin to open until around 1600>1800, but must be supplying full vacuum while cruizing.
When it truly begins to pass vacuum, while driving, is somewhat dependent on the Idle-timing. The more you start with, the more power the engine will have, and the less throttle it will take to deliver a given roadspeed, and so, the VA will come in later. That is working backwards. You want the VA to come in as early as possible, cuz it can supply way more advance than the centrifugal advance can, over a much smaller rpm range, at part throttle.
Here's what I mean;
Say your idle-timing is 14* and say you have 20* in the mechanical that begins coming in at 1000, and is all-in by 3400. Your rate of advance is thus 20* per 2400rpm, which converts to .833 degrees per 100rpm.
So say your VA begins at 1800rpm and you are cruising at 1800rpm. Your timing will be, 14* from the initial, plus 8x .833, plus zero from the VA=
20.66
Now, lets change the idle timing to 6*. The engine has thus lost a lot of idle power and will continue to lag. But to get to 34* @3400rpm, the rate of advance will have to be changed to 26* over 2400rpm which is now
1.083 degrees per 100 rpm. Therefore, at 1800, your total mechanical timing is 8 x1.083 plus 6= just 14.66, but say your VA began working at 1600 now, because of the less power the engine has, that requires a larger throttle opening; and lets say the VA has 22* capacity and Say it's all-in by 1800, Ok so 14.66 +22=
36.66 ...... compared to 20.66
I rest my case.
Obviously I am making up numbers and terminology to prove my point., and some things do not work exactly as I described, HOWEVER, the point remains the same, which is to, at Part Throttle, bring the VA in as soon as possible, as fast as possible, and as much as possible, until it's too much, then take a lil out, bit by bit, until it's drivable without detonation.
If you try to sneak up on it from the bottom, it'll take you all summer to find the sweets spot. Maybe two summers.
There is no 22* VA available over the counter.
and yours appears to be a real loser supplying only 40 less 34=6degrees. I gotta wonder if the diaphragm is perforated.
But I have not seen a VA that can not be modified to at least 22* simply by filing the stops down. IDK how much your engine can tolerate. or should I say wants., and that is gonna change as your Power and Stall-timings get changed. The point is, to hold off modifying the VA until last, to avoid back-tracking, which will require a second VA unit, cuz once the stops are filed off, there's no going back.
You can monitor your sparkport operation by Tee'ing into it with your vacuum gauge.