Ignition box query

Well 'stang, you asked so here goes. The MSD 6a is a piece of junk. They will just go away for no reason at all.
The Ford Motorsport I believe is no longer available. It was a MSD 6a in a Duraspark II box with a plug in rev limiter. I have a pile of three of those that are, hum...non-functional and non-repairable.
The Ford Duraspark II ("brown wire") is your best bet in that type of ignition. Make sure, double sure, triple sure, that the coil matches the box. Do not leave the ignition on with the engine not running. It will cook the coil.
Because of this I may in fact go back to the Petronix in the stock sigle point distributor. I don't know if I actually will. It will be a spur of the moment deal like the next time I fry the coil.
If you are starting with the single point, save yourself alot of grief and just go right away to the Petronix.

70 Stang,
Just for more information....I went with the MSD "Ready to Run" distributor, Blaster coil and MSD wires, Motorcraft plugs. I have not had a problem with it so far. However, I don't drive my car very much. But the times I drive it fires right up it runs really good. There was a Petronix system on it when I bought the car.

The advance mechanism of a Ford Duraspark distributor "in good condition" starts scattering spark somewhere above 6000 rpm, but up to 6000 rpm it is a good distributor. When things start wearing it needs to be pulled & rebuilt.

The MSD is a much better distributor for operation at higher rpms. What folks like about the MSD distributor, compared to Mallory, Accel, etc, is that the pick up in the MSD is a Ford pick up, inductive rather than optical, and is equally reliable as the Ford unit.

The boxes are a different story. The MSD boxes have always been a reliablity handicap. I like the Duraspark boxes too, my recommendation always being the Duraspark I box (red strain relief) that was installed only in California cars, and only for a couple of year models. I have that info at home, if you want it let me know & I'll post it this evening. This particular box has no ballast resistance in the supply circuit, it runs on the full 13 volts, measures & controls current to the plugs, and is supposed to have a hotter spark. Having no ballast to worry about makes the box that much easier to install. I retro-fitted a bunch of these modules into older Fords back in the '80s.

Although I have never done it, it should be possible to wire an MSD distributor & a Ford Duraspark module to work together, this would be the best of both worlds.

Another popular module for converting ANY vehicle to electronic ignition is the Chrysler module used in their vehicles in the late '70s. It is a simple module, easily adaptable, inexpensive, produces a good spark. Lots of info on the 'net about installing it in just about anything. Mark Mensen will like that one.

For racing & high rpm use, it's best to run two of the expensive transistorized, capacitive discharge ignitions, with a cockpit mounted switch to switch to the back up module when the primary module fails. In other words, you accept the reliability issues of the CD modules & plan for an inevitable failure by installing a back up.

Your high voltage friend on the DTBB, George

I have had a complete MSD setup for about 5 years now,The only thing that ever failed was the distributor, and that was caused by the pickup rusting and breaking, due to moisture build up from condensation under the cap. The new cap has a vent hole in it to prevent that problem. I have a friend who had a complete 6A box and Blaster Coil that were slightly used. I bought them from him and mounted them next to the others on the firewall. MSD sells a switch where you can switch back and forth between ignitions so that if one were to fail you could switch over to the other one. I am in the process of making my ignition system "redundant" with the exception of the distributor.

As it is right now if something goes I would have to move the wires around, but I should have the parts there to get me home.

Gary #06984

It seems with MSD, either you have luck with it and no problems or the direct opposite. I run 6AL box and a ready to run distributor which I can run independently in case the box dies. I have had no problems and it runs great, made a huge difference from the stock dual point.

I purchased a complete stock Duraspark distributor, inginiton box , coil, wiring harness, from a local auto parts store. I used to race this combo and grind off the vacumn advance and change the springs on a big block C/SA Comet and wound it to 7000 rpm and never had any problems. Although I would mind a few tips here if some one thinks this is a mistake. I was thinking on the lines that the 351 C I have is basiclly stock and not going over 6000 rpm so I figured stock Duraspark was fine ???? but I'm open to suggestions ??

Just my two cents.

MSD setup:

MSD #8577 Magnetic Pick-up Distributor
MSD #8203 Blaster Coil
MSD #8920 Ford Tach Adapter
MSD #3119 8MM Silicone Spark Plug Wire Set
MSD #8581 Bronze Distributor Gear
MSD #6420 6AL Ignition Box with Rev Limiter
MSD #8746 RPM Module Kit 6000 - 6800

After years of hi rev missing and hot start problems, I installed the above. It seems bulletproof to me so far after almost 5 years and has never failed to start or spark.

But if I was plannng to drive from Montreal to Vegas, it would probably be a good idea to double up based on what I see here!

Duraspark is good to about 7500. It wobbles around a little with the vacuum module but so does every unit with vacuum. If you pin the plate it will go to about 7800. Over that it needs some help.

I've been running essentially the same system as Deeb for the past several years with no problems. Having read many posts on other Forums that attribute the failure of many 6AL boxes to excessive heat, I chose to mount mine in the front trunk away from the engine heat. Hopefully, this will help solve the failure problem - we'll see.

Bob

I have been using a MSD 6AL for about ten years with no troubles. From experience, make sure the Alt.is working properly cause the box does not like AC current(bad diode). I have a noise filter installed, per MSD, in line with the power and ground to keep this failure from happening again. If you install a complete system from MSD and have a roller cam, install a steel gear cause you will have to remove it later to fix a failed bronze gear. Also, depending on your car, make sure you have 12 volts on the switched power wire. Hope that whatever you decide to do, have backups. I always travel with extras, just in case. You can't have everything, but the box would be the minimum needed or go dual system.