Hey guys I'm running a blowthrough set up and would like to get more trailing spark. I'm already running the 2nd gen directfire with a 6A on the leading. I have an extra 6A lying around I want to use on my trailing to get more spark. Whats the best way to hook this up? Wiring diagrams would be nice!

Thanks, Ed

 

You will have to run the spark through the dizzy cap still on the trailing. Wire up the 2nd MSD just like the leading, but get the input from the trailing ignitor/VR sensor. Use the MSD to fire the stock coil or some sort of aftermarket (MSD Blaster 2 or similar). The routing of the plug wires will remain the same as stock.

 

So I get rid of the trailing ignitor as well? Theres a blaster coil on there now.

Thanks, Ed

 

Yeah. The MSD has red/purple wires (I believe) that connect to the VR sensor. That is probably how your leading is wired.

 

MSD magnetic pickup wires are green and purple connect MSD green to Mazda pickup red wire. Connect MSD purple to Mazda green. Don't even have the ignitor in the circuit. Just remove it and store in a safe place.

Route the trailing plug wires through the leading part of the cap. It sounds to me like you have a 2nd gen coil on leading, so the leading part of the cap should be unocupied. It's better with only one gap to jump.

 

Yeah guys! I already have the trailing wires on the leading part of the cap. I'm just tired of flooding the motor and fouling plugs on start up( new rebuild).

Thanks, Ed

 

I have the exact opposite going on. It's a fresh rebuild with the largest street ports I've ever attempted. I cranked it off and on for a minute or two to build up oil pressure. Then I hooked up the fuel pump, filled the carb, tapped the gas pedal a couple times to get some accelerator pump shot into the engine, and it fired up within two seconds of cranking and was able to idle all the way down to 600 RPM within 5 minutes of run time. Holy crap!

To test whether it was a fluke, I shut it off, waited a few seconds, and it fired right back up easily.

I'm not sure what the differences are between yours and my setups, but this engine had a little missing chrome in the rotor housings, though it doesn't seem to be a problem. The apex seals are new. It's in my REPU with DLIDFIS, an Hitachi carb, stock REPU intake manifold with channels cut to connect primary to secondary runners like a '79-'80 Sa manifold (I think I have those to thank for the easy 600RPM idle due to the stronger vacuum signal) and a stock exhaust manifold and one glasspack temporarilly shoved on a short downpipe. It's loud, but idles smooth and revs pretty well even with the stock heavy REPU 30lbs flywheel.

I once tried an MSD in this truck and didn't like it. Good luck with your MSD endevours.

 

I just got back from my test drive around the block after the 6a install on the trailing. The car feels like it has more torque and revs a lot quicker. I just managed two quick pulls in 1st gear from a dead stop. 10psi and 8000rpm came quick! I still get a little lope at idle but I think thats from the streetport.

Thanks for the help guys! Ed

 

That's good news but how recently was it rebuilt? I hope you're not flogging a fresh rebuild.

 

100 miles on it LOL!

Ed

 

See FD forum for weather "flogging" is appropriate on rebuilds.