Programmable MSD 6AL-2 questions
 

I am swapping out the CCC Quadrajet, Distributor and ECM for a mechanical Quadrajet, Pro-Billet MSD #85551 Distributor and MSD #6530 Programmable MSD 6AL-2 ignition box today. The CCC system ran very well but I had a few issues with it that were not correctable so I decided to go this route vs upgrading this engine to EFI.

After gathering up most of the parts, I put power to the ignition box on my bench to test and make sure the serial to usb adapter I picked up would let my laptop see the box, it did.

I bought the box gently used from a somewhat local guy that told me he had changed the rev limiter and timing curve in it, so I tried to view them to change them back to a somewhat factory default setup for my initial start. I found the rev limits easily and could change those, but in the MSD Pro-Data software I can not figure out how to see and\or change the timing cure. I"m certain I'm just not pressing the right button or something stupid but it has me befuddled. Is anyone proficient in using this software that can help a newbie get his feet wet in this area?

My engine is a crate GMPP HT383, basically a 9.1 compression, vortec heads, Camshaft Type (P/N 14097395): Hydraulic roller Camshaft Lift (in.): .431 intake / .451 exhaust Camshaft Duration (@.050 in.): 196° intake / 206° exhaust with an aluminum dual plane intake and 1 5/8s mid length headers.

It shouldn't take anything really radical or special for a timing curve, the book suggest 32 degrees total timing with a 6000 RPM max. Cruising RPM is 1700-1800 RPM in 6th gear and the car weighs 3500#s or so. I probably could have gotten by with an just an e-curve MSD with or without a 6AL box, but I picked this box up for a decent price and MSD said the best distributor to use with it is the 85551. Plus, I like tinkering with things and this box will really let me fine tune the ignition for my needs.

Anyway, I realize this isn't EFI and computer timing, but if anyone used to mess around with old school ignitions and primarily has used this programmable ignition box and software and can help a newbie learn it, that would be great. I kind of want to make sure I know what's in the box before I fire it up for the first time if you get my drift.

Wow, I must have had a really good night's sleep because I dove back into the software and I discovered the "add dot" button on the timing graph and I am not plotting a timing curve!!! :idea: :computer: :clap:

So, given my engine parameters above...should I put it at -22* at 0 RPM and ramp it up to 0* say at around 2000 RPM for an initial set?

That would be like 10* initial timing with 32* total, correct? That puts the cruising advance at about 26-27*.

You can add a MAP sensor input to the box and tweak advance vs. engine vacuum. It actually works backwards... you add advance, then pull it out based on a vacuum vs. retard curve. This will allow you to run more advance under low load...

Make sure to lock the distributor.

Also look a the programmable start retard function. This box has a lot of cool features.

I did get the distributor locked out and got it installed in the car. I'll have to wait until I get some expert carb help to straighten my q-jet out before I can attempt to fire it up though.

I did read that about the MAP sensor. I actually have a MAP sensor on the car now that the CCC system used. I need to do a little digging to see which one it is and if it will work for this application.

I'm pretty stoked about being able to fine tune the ignition side with this box, should be fun.

Transferring the file to the MSD...

https://lh3.googleusercontent.com/-d...102754_147.jpg

The basic timing curve I'll start with to get it running.

https://lh3.googleusercontent.com/-H...102818_165.jpg

With the factory ECM and harness out of the way, it looks like the new MSD box will slide right into the pocket the ECM used to set in and the wires will feed right out the same hole the CCC harness used.

https://lh3.googleusercontent.com/-Y...o/DSC06048.JPG

https://lh5.googleusercontent.com/-A...o/DSC06047.JPG

https://lh5.googleusercontent.com/-Q...o/DSC06046.JPG

Does anyone see any issues with me just sliding the MSD box into this slot in the plastic kick panel to hold it in place?

It almost seems too simple and easy... :D

There isn't room in the slot to put the rubber feet the MSD box comes with though, the box itself just barely fits into the plastic pocket. Not sure if the box creates too much heat for the plastic or if the plastic will transfer to much vibration to the shell of the MSD box? I can't imagine either being a problem though as the box is digital now and the factory ECM has been riding in that slot for 30 years now with no issues.

Lance, i ran MSD in my racing days, and I'll tell you, I always had a spare one in the hauler, wired up with quick connector, ready to go. I can honestly say that I had more MSD box failures, than I had flat tires, in all the years I raced. If I were you, I'd get a spare box, and have it ready to go.
I ran the 6ALN box, which never really got hot. I'm not sure about the particular box you have, as far as heat goes, but I'd think that there would be ventilation in the kick panel area? I don't feel that vibration or harmonics should be an issue from the plastic panel. If you strapped it directly to something metallic, that would be a different sermon. I like what your doing with your car this winter.

Thanks Scott. MSD says in their instructions that they do not recommend installing the box in an enclosed area like a glove box. This area has open slots on the top, bottom and toward the firewall for air to circulate through but would have plastic right up against the top and bottom of the box. With the box being all digital I can't imagine vibration or heat being an issue...plus it'll be a much nicer environment for the box there than out on the inner fenderwell.

I'll probably wait and ask the MSD tech on Monday before permanently running the wires but I think this is where it's gonna end up.

Looks like MSD approves of the spot...

Alright, an update... I've had the car running again for about a week and man, what an improvement in horsepower so far. Haven't had it back to the dyno yet but my butt dyno approves so far.

I ended up plotting the retard curve to 7* advanced at idle (20" vacuum) and a pretty linear curve starting at 1000 RPM at 7* ending at 32* advance at 3000 RPM. I believe it would actually like a little more timing on the top end and a little less timing at idle but the box is limited to 25* of retard so this is the happy medium so far. It runs great, starts great, idles great, and I haven't heard even a hint of detonation anywhere and I've tried to get it to ping.

Okay, I have a 1 bar MAP sensor hooked up to the box and manifold vacuum...but no boost retard curve plotted yet. This is where I need a little bit of laymans help once again helping me understand vacuum advance and how to use it to better the performance from my car.

I finally have almost gotten used to thinking about timing advance in reverse with this box...but vacuum advance, boost retard is still real foggy to me...not to mention how to set it up to work best in my situation.

Here is my graph at idle as it sits now.

https://lh3.googleusercontent.com/-V...0307151129.jpg

and like I said it's pulling 20" of vacuum at idle

https://lh6.googleusercontent.com/-s...307151129a.jpg

When I had the initial at 10* it was idling at 1100 RPM and pulling 23" of vacuum.

Can anyone help me with a easy to get tutorial on how to set up a boost retard curve that will help this engine using the MAP sensor?

Or just tell me what I need the MAP sensor to tell the box what to do...where and when do I want it to add advance and where and when do I not want it to add advance?

If someone can help get that through my thick head, I believe I can figure the rest out. I have to say, it was pretty effing cool to grab a dot on the graph, drag a line, and hear the engine change when responding to the change I made. I really dug that. I believe I could do the same with the boost retard curve, I just need to understand exactly what I'm trying to do first.

Thanks...