Hey everybody I've converted my FC3S to carb and have been researching how to wire up my ignition using an MSD 6AL and 3 MSD Blaster 2 coils and using a distributor out of a 81-85 with the magnetic pickups. Well, anyways I think I have it figured out and made myself a wiring diagram and wanted to see if any of you see any issue with it or see something that won't work. Thanks ahead of time!

 

Don't know a lot about MSD but you aren't using the leading ignitor or its been gutted right?

You can move your trailing wires to the leading wires on the dizzy to make it a bit more efficient.

I assume the 2 + leads to the MSD, one of em turns the unit on from the switched ignition. If
thats true then I think the diagram looks ok to me.

 

Thanks for the response, yes the leading igniter is gutted and modified to work with the MSD.

And you're correct with the two + leads on the MSD one is the ignition switch on/off wire and the other is the main power.

And can you explain moving the trailing wires to the leading leads on the distributor bit? It won't affect the timing any at all? I thought leading fired at the same time, with trailing having to fire at different times.

 

If you study the dizzy cap you will see it makes no difference. The spark is contolled by the
signal to the ignitor from the dizzy magnetic pickup. The cap controls which plug gets fired. Now
your leading plugs don't go through the dizzy so they both fire at the same time always. Thats
the dual part of the name, its a wasted spark ignition.

 

So why or how does putting the trailing wires on the leading spots on the distributor cap going to make anything better? Does the leading spots on the distributor have a stronger spark than trailing side?

 

Pull the cap and look at the way the leading and the trailing path are routed by
the rotor. The leading is the shorter path, therefore a better solution.

True story time. I had my ignition setup for leading only DFIS using TFI coils. It ran
great and the thread for doing it is in my signature. Well, later I decided to add
trailing ignition as well. I wired it all up and ran the plug wires and fired it up. Ran
ok at idle, the leading timing was still spot on but the trailing was way off. Turns
out I had my dizzy stabbed 90 deg off since I did the TFIDFIS mod. Didn't affect
the leading ever because it was wasted spark and just needed to see a signal
every 90 deg anyway. Trailing on the other hand was all messed up because it
goes through the cap and was 90 deg off.

 

I used this diagram to wire up my 6AL and I cant get it to start. I gutted the leading igniter as stated here MSD 6A direct fire Ignition for Mazda RX-7 Rotary Engine ? Dr. Scott M. Baker