(NOTE: Cross posted from 1st Gen forum) Hello folks. After having spent several days of searching the forums (here and elsewhere), I'm entirely confused as to how to wire my ignition setup properly. I bought the race car back in 2018. It's a 1979 SA22C race car. It had two MSD 6AL boxes (6AL not 6AL-anything, just 6AL), two horizontally mounted ignition coils and a newer (1982?) distributor with igniters (taller distributor cap and rotor). The car barely ran because of carburation issues. Anyway, I re-wired the car except for the ignition system which I left alone. I managed to run the car through two short road racing seasons although I felt that the car was woefully underpowered. Last year, I upgraded the ignition coils to oil filled MSD Blaster 2 coils and I mounted the coils upright. I ran the car for another two races. Earlier this month, I was in the process of checking ignition timing and one of the MSD Blaster 2 coils melted. The leading ignition on rotor 1 was spot on but the leading ignition on rotor 2 was all over the place (just pulsing quickly but nothing was lining up with the pulley marks). When I checked the trailing on either rotors, there was nothing, not even a pulse on the timing light. That's when I saw the coil smoking. The ignition wiring was a mess with plug wires bundled up along with the wires to the signal wires to the igniters. I figured that there was a lot of cross talk and inductance happening. I gutted the entire wiring mess and decided to re-wire the ignition system from scratch. I remounted the MSD boxes from the cockpit to the front left side strut tower in order to shorten the wiring to the igniters. I also bought two new MSD Blaster Solid State coils. I eliminated the crusty, stiff and old 8 foot long MSD harness along with the connectors. Now I only have two 10AWG silicone wires (red) from the cockpit mounted kill switch to the MSD heavy red + (one for each box) and connected the MSD heavy black (-) to freshly mounted chassis ground. I also put some EMI shielding on the wiring to the igniters and to the coils to play it safe. This is where I am confused as to how to wire the rest of the ignition. Unfortunately, I stupidly did not make notes of how the ignition wiring was set up prior to my ripping everything out (frustration had set in). I am also unsure about the correct wire positions on the igniters themselves since the car never had the "T" shaped factory connectors to them and I've been unable to find a photo showing the polarity. I found the wiring schematic (attached photo) from this forum but I'm confused as to how this will work since the MSD box is directly wired to the battery but no wire from the ignition switch to turn the MSD on or off. Aren't I supposed to feed 12v from the ignition switch to the box? I called MSD Tech Support and they said to follow the schematic on page 10 (see attached photo). If so, that would mean that the white wire from the MSD box connects to the (-) post of the igniter. But how would I wire the igniter, i.e. what about the (+) post on the igniter? I apologize for the overly long and rambling post and I thank you in advance. EDIT: I do not want to go direct fire at this point. I just want to run one MSD box for the leading and one MSD box for the trailing.

 

I figured out the wiring. MODS, feel free to close this thread. Thanks

 

Mind telling us how you wired it up? I’m looking to do this upgrade and it sounds like you got it figured out.

 

Could you post some pictures of how you ended up finishing this?

 

The first illustration in the first post answers your questions assuming you are going to continue to use the OE Igniters. Just follow the diagram.

• Use an MSD 6A box and not a 6AL. Rotary engines do not need rev limiters
• The MSD 6A Digital boxes work fine and you do not need to set cylinder count with a 6A box
• The MSD boxes should be cushion mounted (use the MSD rubber mounts) and should be located in a cool place (I mounted mine in the interior of the car)
• I would not bother putting an MSD on the trailing ignition - it is a waste of time and money
• If you do decide to use a second MSD, keep the wiring for the two boxes completely separated because cross talk in the wiring between the two boxes will cause issues
• Keep tachometer trigger wiring away for MSD trigger wiring
• Follow all MSD recommendations for coils and spark plug wires
• Use only quality grounds for the MSD. I am convinced that shoddy grounds and power wiring kill more MSDs than supposed MSD quality issues.

 

1 MSD box, 3 coils, direct fire the leading and leave the trailing stock. You will be much happier and not so cluttered under the hood

 

This or use a two pole coil for direct fire to the leading plugs. I am currently use an MSD dual pole coil (it is from a GM application) but have also used a motorcycle coil from a Harley Davidson application.