73StreetRace

Hi there !

So, I just finished installing my new MSD programmable 6AL-2 ignition box.
Seems to be great stuff, as my old MSD 6AL was.

Here are some pictures showing it :















I locked my Pertronix flamethrower distributor out at 36° BTDC, checked and adjusted the rotor phasing.
Mr Gasket makes a transparent distributor cap which is great for this. You don't even need a stroboscopic light, just do it at night,
start your engine and open your eyes !

The plate needed to be rotated by 3.5° to get the best phasing between 0° and 16° run retard.
I kept the adjustable vacuum advance canister and it needed just a slight modification to obtain the necessary rotation.

I'm now running a 16° retard curve, with 0° retard ( all-in ) at 3000 RPM, which means I have 20° initial and 15° ( intake manifold ) vacuum advance.
Total timing w/o vacuum is 36°, determined by the locked-out distributor.
Actually, the curve I've programmed is a copy of the centrifugal advance curve that I had with the Pertronix mechanical advance springs,
except the initial was only 18° before.




Here are some recent pictures of the car :












FINALLY, MY QUESTION IS :

Is it still a conservative curve ?
Of course it's now very easy to try a new, more agressive curve.
But how will I be able to determine if the new curve is slightly better or worse than the previous one ? This is my first digital ignition device and I am a bit confused...
Has anyone already tried this ? Any help or opinion would be greatly appreciated...

MelWff

Have never seen this before but why did you install ignition related components under the front of the car, driving in wet conditions was not a concern?
If I understand correctly the system takes the 36 degress that are locked in the distributor and retards it till 3000 RPM. So according to your curve you have 20 degrees till about 1500 rpm, couldnt you lower that to 1000 rpm?

73StreetRace

Yes, driving in wet conditions is NOT a concern...
My old MSD-6AL has been there for many years and I never had any issue with it. Anyway, the advertised description is that the Digital 6 boxes are waterproof.

I could lower the beginning of the rising curve to about 1000 RPM. It's definitely smth I can try. It just implies that I'll get timing advance sooner :
With the silver distributor advance springs I had about 20° BTDC advance at 1500 RPM and about 16° at idle. So, with the current programmed curve and its constant 16° retard ( 36° - 16° = 20° ),
I already have more advance between idle and 1500 RPM than I had before. But maybe the engine can withstand more.