Fancy Ignition

Post date: Nov 19, 2012 4:23:00 PM

The car was running pretty well, but was having trouble getting a good ignition curve and avoiding detonation. So as usually happens with me, I went off the deep end:

The MSD 6AL-2 Programmable, part 6530. The big blue thing is a 10kuF cap as recommended by the folks at Daytona Sensors. Their CD-1 was *very* tempting, and having the general purpose I/O stuff would be very nice. The lack of live monitoring (and extra cost) was a show stopper for me.

The biggest issue is this makes my distributor investment, well, poor. So this is all that's left of it:

(well, with the shaft, reluctor, etc)

So that's like a $50 HEI now.....

Vacuum and mechanical advance are locked out. I also got the MSD Cap-A-Dapt so it runs a Ford HEI cap and an adjustable rotor. The first firing was interest, as the rotor phasing was pretty bad, so the distributor made a "chattering" noise from all the cross-fires.

Got that sorted and had to swing the rotor all the way to the left, and it still wasn't lining up well. So I tore the dizzy apart and modified the pickup mount plate to move the pickup CCW a bit. The phasing is better, but still a little dicey at full retard.

Current curve is full advance at 48deg. The curve looks something like 20deg @ idle, 36deg all in by 3000 rpm, and the vacuum pulls in 12deg starting about 10" mercury. And now I can fiddle with the ignition as much as I want from a laptop!

To set the timing, I load a totally flat (no retard) curve, fire up the engine and get it timed to the max advance. Then load the correct curves.

The only thing I need to look at right now is I think the full retard at start might be moving the rotor enough to hit the next cylinder (massive advance).

But, no pinging! It's running like a scalded monkey.

Sunday I went after the carb since idle is still hit and miss. Opened the idle tube to 0.040", down channels to 0.059", moved the jets up to a 70. Ruggles specs out 0.070" main air bleeds, and the stock Olds size is more like 0.041"!! I opened those a bit to 0.047"ish.

It'll idle in gear at 750rpm solidly, but that rises to 1100 in neutral. I'm worried about breaking the tranny case shifting into reverse (lesson from experience.....). With these mods, I see a bigger swing between rich and lean at various conditions. Maybe I need to get the main bleeds back smaller? I also want to try smaller idle bypass, but it's hard to drill a 0.050" hole in a set screw....

It's interesting that at straight cruise it runs about 14.5:1, slight lugging goes up to 16:1, but idling down is like 12:1!! Of course, that's like 25" vacuum at speed, while idle is more like 14". Idle screws are still around 5 turns out. So something magic needs to happen here, I'm just not sure what.

And I need to find a source of large numbers of small bits.