MSD 6AL-2 PROGRAMMABLE Ignition Control in a Squarebody, say what?

[Gregski]

If you are like me and like precision, control, and spending money on shinny new parts only to strap them on to your old rusty rig then you might enjoy this thread, I hope you do.

Our Goals:

1. Learn more about ignition timing, timing advance, and it's impact on performance and fuel economy on a street car/truck.

2. Test common theories about ignition timing, ie lock out distributor, vacuum advance vs non vacuum advance, ideal total timing for a street 350 ci small block chevy (ie 32*, 34*, or 36* etc.).

3. Experiment, experiment, experiment with different advance [ahem] retard curves.

DISCLAIMER: This is not going to be about maximum power gains for a race car or a drag strip car, the test subject will be my daily driver 1974 GMC aka Chevy C10 (2WD) V8 350 with a manual 4 speed with overdrive transmission.

Questions / FAQ: here I will keep a real time list of questions, mine and yours

1. Is this ignition box EMISSIONS legal / compliant?

A. No, according to Holley's website: "This part is legal for use on Uncontrolled (Non-Emissions Controlled) Vehicles or Racing Vehicles."

2. Can I use my vacuum canister on my distributor with this box?

A. No, this and any other electronic MSD ignition requires you to lock-out the distributor, this locks both the mechanical and therefor vacuum advance. You can compensate for vacuum using a MAP sensor, more on this coming up, stay tuned.

3. Can I hook up a gauge directly to this box to see my timing in real time as I drive for example?

A. No, you need a laptop for that.

4. What is the maximum amount of retard this ignition box can pull out?

A. All of the retard amounts are cumulative and the maximum amount of retard is 30 degrees.

Resources:

Articles:

Going Digital: MSD Digital Conversion by Jeff Smith written in 2015 for Power and Performance magazine

Forums:

MSD 6AL-2 Programmable: Anyone Running Them? Aussie, Aussie, Aussie Gerg sets the record straight, by far my favorite write up, warning contains some profanity.

Videos:

MSD Programmable 6AL-2 review

I had my eye on this unit for a few years to be honest, but money and other priorities always kept it an arms length away... until this last Christmas...

brought to you by the same dude who posted: INNOVATE DLG1 Wideband O2 Oxygen Sensor Tuning Diagnostics Logging Air Fuel Ratio etc

[Gregski]

and a few days later it arrived, part # 65303, (aka the black one) just want to share a few quick observations

1. the MSD box seemed like it was already opened and then tapped back shut?

2. notice that not only is the picture on the box the red one and not the black one, but it is of a totally different unit, ie the 6AL-2 MULTIPLE SPARK DISCHARGE

3. ever since the Holley investment group started buying up all the independent speed parts, I think they farmed out their manufacturing over seas, and the quality diminished (last time I used MSD plug wires it took 2 or 3 sets to make one good one)

[Gregski]

quick look at what's inside and what else you'll need

note the serial cable (upper right in last pic) nice throw back to 1999, it used to connect this box to a laptop, but these days you can't find a laptop with a serial port (aka plug) so one must go out and buy a serial to usb adapter cable, no biggie, just sayin'

[Gregski]

I will be connecting this ignition box to my HEI distributor so I also picked up this GM HEI MODULE BYPASS CABLE Part No. 8861 for $8.00

I really like the short and simple part numbering scheme Holley / MSD uses, thumbs up

[Gregski]

the ignition comes with a 16 page INSTALLATION INSTRUCTIONS booklet that is out of date as soon as you crack it open for guys like me or you if you are running an HEI distributor, as there is no schematic for it shown among the 5 schematics that they do include

I also thought the two blank figures, Figure 10 and Figure 11 were a nice touch, who says Engineers have no sense of humor

Luckily we can easily download a more up to date 20 page set of instructions from Holley's website https://documents.holley.com/6530.pdf

[Gregski]

I looked for YouTube video's for a while before I bought it, though most of them specialized in unboxing, ha ha, seems like the thing to do, where the guy holds the camera in one hand and tries to unbox the item with the other, you've seen them

and I also read a few forums and car magazine articles on this thing so I knew you had to lock out the distributor but for the life of me I could not find it in the MSD instructions, it seems important, and it seems like it's one of the first things you gotta do, finally when I found it it was buried literally half way in the manual, on page 8 and this is what it says:

Note: If you are programming the timing functions of the ignition, the distributor will require being locked-out.

[rant] Seriously? was my initial reaction. What do you mean if you are programming the timing functions? Why else would you spend more money and buy this PROGRAMMABLE unit. [/rant]

[Gregski]

ok, so how do we lock-out the HEI distributor, can we do it in such a way that does not require welding anything, you know so it can be reversed?

I like to do things right and keep em clean, so I discovered / came up with this part no 88363 for $14.00

[Tsoptich83]

Looking forward for more to come. Can you list any articles you read? Very interested.

[Gregski]

Originally Posted by Tsoptich83

Looking forward for more to come. Can you list any articles you read? Very interested.

Thank you bud, and a great suggestion, let me share this one by Jeff Smith written in 2015 for Power and Performance magazine:

Going Digital: MSD Digital Conversion

[Gregski]

as I mentioned earlier the instructions that come in the box do not include directions for the HEI distributor, but the ones we can download today, introduce 4 additional pages and among them we find these two sections

the first is how to identify which one of the many HEI distributors you may have, four, five, or seven PIN, technically which ignition "banana" module your HEI distributor may contain

the second shows us how to hook it up to the ignition

and while we're harping on the instructions, MSD could not have made this section on how to remove the module and replace it with the wiring harness if they tried, ha ha

[Gregski]

I do not mean to continue harping on the MSD instructions, but if you Google how to setup this ignition you will hear many voices on different forums echo my sentiments. So don't feel bad if you are lost so far.

We need to start somewhere so might as well start with prepping the distributor. What do you mean prepping? Do you mean locking it out? Yes, well why didn't you just say that? Because we also have to castrate it sort of speak. What? We need to remove the ignition module out of the distributor, essentially disarming it if you will, as well as remove the vacuum canister (optional) but it won't function after the lock-out anyway.

This is obvious to some, mostly those who have been running an MSD Ignition box already, but it is new and not so obvious to the rest of us, so please be patient.

Our subject is a genuine GM Part No. 93440806 HEI Distributor complements of Mexico

(forgive me while i recycle some old pics from my Restoring Rusty) [shameless thread promotion].

[Gregski]

In my opinion the High Energy Ignition (H.E.I.) as it is called should be called the All-In-One ignition and here's why.

In one box, or in one self contained aparatus we get all these things:

• distributor
• ignition
• coil

no extra spark plug wire to run to the coil which needs to be strapped to the engine block somewhere or on the firewall, no extra electrical wires to run to the external ignition box mounted on the inner fender somewhere, you get the idea

Now let's review what's the job of the distributor (a stand alone distributor or just the distributor part of our HEI)

It is to do two things:

1. report to the ignition the crank position. Say what? The ignition needs to know where the piston is at as it travels up and down. The piston is moved up and down by the crank, so the crank position correlates to the piston position, but let's not geek out too much. Bro, the distributor is driven by the cam not the crank. Yes, but the timing chain joins the crank sprocket to the cam sprocket. So the crank signals the cam via the timing set, then the cam signals the distributor via it's shaft, and that signal goes to the reluctor?, etc.

dude you lost me but whatever, yes this is inefficient and that's why on modern cars they have something called the Crank Position Sensor. but that's getting off topic

2. the second job of the distributor is to get the orders from the ignition when to fire the spark and tell the coil to fire

sorry, had to get all that out of the way

[Gregski]

ok by slipping off the connectors off this ignition module, (actually had to remove it out completely to be able to unplug it) we can identify it as the four PIN module, allowing us to match it up to the proper wiring diagram

now I took the left plug off of it to show you that it's a 4 pin banana, but it can stay on as the whole thing has to be replaced, the module with the stock factory pig tail if you will

and just a reminder, I am just a newb trying to figure this out, so please give me feedback / comments as we go along, this is to help everyone out, if you see me doing something dumb, please correct me, I am here to learn myself

and forgive me for being repetitive and even reposting some pics etc. Think of the guys who will find this 2 years from now and will want a stand alone post on the issue they are having, a lot of times we don't want to read an entire thread (allthought I think we would be better off if we did, ha ha) I know I am guilty of that myself as the frustration sets in at the time

[Gregski]

those of you who follow any of my other threads, know that The Greg is all about the mandatory Stare and Compare, ha ha, hey I find it's a good way to learn, so maybe it helps somebody out

here we look at the old original ignition sometimes called the "banana" module, so that's where that comes from, and the new module eliminator wiring harness / pig tail, really you can make this on your own, two pieces of wire two different width blade terminals, and Bob's your uncle

[Gregski]

let's take a look at the HEI distributor with the internal module removed and the MSD 8861 module bypass cable installed

couple notes, and warnings

those two wire clamps are not application specific, they look like something you can pick up at your local Hardware Store, so if you can get ones that are a bit shorter I would suggest that, also be very careful how you thread the wires through those loops as they can get pinched very easily upon screwing them down, and cause a short

same goes for the rubber O-ring, it is not going to be water tight by any means, you've heard of trying to fit a square peg in a round hole, well this is the opposite, but still comical, I show it pictured without the lid so you can see the air gap, but even with the lid firmly on it has a gap, on mine anyway

OK, so at this point we have basically told the distributor to Observe and Report, don't take any action on your own, you are no longer in charge (pun? I crack myself up sometimes), the new shinny MSD box will do all the talking.

[Gregski]

OK, with the ignition module removed from the HEI distributor we are half way there with having it be ready to go. For those of you with non HEI distributors you distributors may not have ignition modules in them so you could have skipped that step.

So now we will remove the weights and springs from our distributor (this goes for all (non already locked out) distributors and lock it out.

Wars have been started over how to do this, so put your propane torches down and please bare with me as I take the reversable method. What do I mean by reversable? Well, I do not want to damage or sacrifice a perfectly working distributor by making any irreversible permanent changes to it, such as welding, cutting, or drilling into any of it's parts. Some of you may agree, some of you may be in a different position, which I respect as well, to each it's own, that's just Hot Roddin'.

so we remove the cap and rotor (the white plastic thing) and expose the weights and springs

then we remove the weights and springs

(and via TV Magic the banana module disappears and the bypass harness appears, ha ha) again using some old pics cause I'm lazy, but you get the idea

then slip on the Mechanical Advance Lockout for GM HEI Part No. 88363

...um mabye not so fast!

[hatzie]

Honestly it's more than a little obnoxious that MSD and others charge a mint for pigtails with unsealed connectors (Molex, Packard, Metripak etc), bullet connectors with seals that are not rated for the underhood chemicals and temperatures, dangling blade disconnects, and Scotchloks in these kits instead of stepping up and making a mating connector that bolts down in place of the module and also includes a wire exit seal/strain-relief.

Those kind of hokey cheezy schlock things makes it look like they're being built by teenagers in someone's garage instead of a real manufacturing outfit.

Hopefully they've stepped up and stopped using PVC jacketed wire in favor of Crosslink Polyethylene that's been the standard wire jacket of choice amongst auto manufacturers for around 50 years... but I doubt it.

USB is serial it's a different connector, voltage level, and data transport timing protocol. RS232 and RS485 serial is still being used on brand new test and measurement equipment. Thankfully IEEE-488 is pretty much gone now.

[Gregski]

the MSD lockout plate won't go on, on all four posts simultaneously, as you will see in the pictures the holes are the right size as they fit on the individual posts, but I recon the outer two are slightly misaligned

not a big deal, just reporting my experiences

I can't slip it over just the outer two because the middle ones are in the way, but you get the idea of what I am trying to test here

[donw1986]

Just wondering if you know if this will work on an 86 that has factory electronic spark timing, i dont have vacume advance, and if it would still interface with the check engine light since i live in commifornia and must have the check engine light working to pass smog here, i have the msd atomic efi installed and that does comply with calif smog

[Gregski]

Originally Posted by donw1986

Just wondering if you know if this will work on an 86 that has factory electronic spark timing, i dont have vacume advance, and if it would still interface with the check engine light since i live in commifornia and must have the check engine light working to pass smog here, i have the msd atomic efi installed and that does comply with calif smog

Hey bud, I hail from Kalifornia as well, aka the land of REGULATIONS, super unfriendly to us car guys. I am surprised you can even get it SMOGed with the Atomic EFI. I'm sorry but I do not know if you can use this in your rig, I would think the unit you have is much more better than this as it costs like three times as much.

Gleaned from the MSD website:

This part is legal for use on Uncontrolled (Non-Emissions Controlled) Vehicles or Racing Vehicles.

The following vehicles are considered Uncontrolled (Non-Emissions Controlled) Vehicles:

1965 and older U.S. manufactured California Certified vehicles
1967 and older U.S. manufactured Federally Certified vehicles
1967 and older Foreign manufactured vehicle
Racing Vehicles are vehicles that are used exclusively for racing or other forms of competition that are not registered and that may never be used on the street.

[Gregski]

hello old friend, can you help, please and thank you

so I used gentle persuasion on the two outside holes, filing with the rat tail file tiny bit at a time until the plate slipped on real tight

[Gregski]

Now can we stab that bad boy in? Nope, not yet. We can also remove the Vacuum Canister. It is already rendered ineffective so keeping it on only risks interference with the intake manifold as we try to twist the cap in order to set the total timing (spoiler alert!)

But Greg won't not having Vacuum advance effect fuel economy and perhaps even driveability? Yes with an explanation (and an eventual remedy).

We must realize that although MSD started out in the 70's as a company that was striving to develop leaner burning fuel systems to increase engine fuel efficiency. Shortly after coming onto the market, the new ignition system was also shown to work particularly well in racing applications in 1976. Word of mouth among top racers helped the product and the company's popularity grow. thank you Wiki

So MSD makes racing parts, as evident by their Pro-Billet Distributor Part# 85551 "This is our most popular performance distributor!" they claim

Question is: Do you see a vacuum advance can on that bad boy? Exactly, fuel efficiency takes a back seat to performance, so off with the vacuum can so we can be like the guys racing in a straight line on TV, lol.

I recommend you put the two screws that were holding the vacuum can aparatus back in the housing since their holes are open to the bottom of the unit.

We now also need a block off plate to keep foreign matter out of the distributor. Luckily MSD has already thought of that Part No. 8468 $9.00

[hatzie]

MSD 8468 locks the vacuum advance tab on the ignition pickup assembly in one location so it doesn't move around and make your timing float. Blocking the hole in the side of the distributor is secondary to the real purpose of that part...

[Gregski]

Originally Posted by hatzie

MSD 8468 locks the vacuum advance tab on the ignition pickup assembly in one location so it doesn't move around and make your timing float. Blocking the hole in the side of the distributor is secondary to the real purpose of that part...

Copy, I think PART# 88364 is actually the one for the HEI, but all I need it for is to block the hole. I rather buy something and spend time fidlin' making one, they are so cheap.

[hatzie]

88364 has the lock for the advance arm sticking out of the pickup assembly too. I wouldn't recommend leaving it out.