So I was swapping out my Mallory 6A ignition for a MSD 6AL. There was about 1 month of down time from when I removed the Mallory and installed the MSD. So I got the MSD from evilBay and installed it. Nothing happened. Car ran great before removing the Mallory. I called MSD tech support and they said my box was dead and I could send it in. So I did. But instead of waiting for it to come back I went ahead and bought a new one from Jegs. Got it installed and still.. nothing. Using the troubleshooting sheet that came with it, it suggested that the coil might be bad. Though full of disbelief that this could be the problem, I went and got a new one anyway. I plugged in in and it lit right up. Now the question is, how did my coil go bad by just sitting there? In general what makes coils go bad? Heat? Mine is located in front of the drivers side head. Do I have mine mounted in a bad spot? My coil wire is not long enough to mount it anywhere else. Where do you get longer coil wires?
Chris, they can go at any time, like any other electronic component. Mine is located in front of the head on the drivers side also. I think it was just time for it to go. I lost a second in my 1/4 mile times and thought it was the convertor. Put in a different convertor-no change. Sent the convertor out for rebuild. Did the tranny while it was out-still no change. Replaced carb, plug wires and a bunch of other stuff-nothing. Finally, one day I took an old MSD-6 that I had and swapped it out and gained back my second. Did I mention that I hate electrical problems.
Funny how these things happen. When I got mine back together in the resto, I had installed a brand new stock coil. I got the motor fired up, it ran about 90 seconds, and died. It wouldn't restart. Carb? No-bought a new one anyway. Started it up, same thing, dead in a couple of minutes. Adjust the valves the next day. Same thing. Runs for 2 min, off when it gets hot. Found an old coil in the garage with a 1973 date on it. Plug it in. Runs like a champ-had to tighten the valves back up and apologize to machinist for asking him if he made the tolerances too tight! Seth
I left my key on for a couple of hours one time (by accident). I went out to the garage and found a puddle of oil under the front of my truck. Lifted the hood and found the oil had bubbled out of my coil. It was an Accel Super Coil. That thing was smokin hot too. I am not sure if leaving the key on smoked the coil or the coil was about dead and by coincidence I left the key on? Cleaver
A coil is no different then a transformer, you have a primary and secondary windings, it basically takes 12v and steps it up to 30-50kv ,the primary winding is what flows the current from points being closed or electronics and when the points open the current stops and the electromagnetic field collapses inducing a voltage in the secondary windings. There are two types of coils, internal and external resistance. If you use a external resistance coil with no resistor it will burn open the primary coil windings, you can test it with a ohm meter, with the coil disconnected from power connect a ohm meter to the + - terminals and it should read from a couple of ohms to a couple K depending on if its internal or external resistance. Ford in the 70s used a resistance wire from the ignition going to the + terminal of the coil and at one time used a thermister wire(which increased resistance when more current was present), both were to reduce the current going to the coil, Ford also allowed direct 12volts to goto the coil from the starter soleniod relay (s terminal) this was to help assist in starting but was only during cranking. So for your situation either you hooked up the coils wrong the first two times or the ebay one and Jegs one were used and burnt out or possibly defective (low chance because they are supposed tested at the factory) I'd test the 2 bad coils with a meter , + to _ should get some reading , + or - to center post (should be open) ,and + or - to casing (should be open or if its a plastic case it doesn't matter), make sure you read the instructions to see if you need a external resistor with this coil, also to note vibration will also kill a coil, it will cause the connection from the windings to the terminals to break but not having the coil resisted when needed is the number one killer.
If you have a after market coil the requires a external resister and don't put one on ,cooking is what will happen if you leave the key on and the car is not running. The original factory setup from ford will not do this.
I just saw on TV that because coils are filled with oil, to mount them horizontally so that the small terminals are down and sure to be submerged in case there is an air bubble in there. Supposedly will run cooler. Never had a problem with one, but thought it was an interesting theory ... might also be ...
I've had two coils go bad in the last 6 months. One was a blaster coil and the other a stock style one. I attribute it mostly to vibration and heat (one was my sons race car mounted on the front of the motor and the other one was on my stock truck). Both can kill a coil. Like the name implies (from a simplistic point of view) it's just a coil of (very thin) wire around an iron core that is bathed in oil to keep it from overheating and shorting or melting. It happens and sadly you don't usually get any warning before they go.
Are you running the stock style coil on the system? If so that is your problem. You need to run a coil that will handle capacitive discharge and multiple spark. Stock coils will work for a while but in the end will meet a very early death. Even the Blaster coils are not designed for the Multiple Spark Discharge systems. Get you a good Coil that matches your system.
Add a resistor to the power wire going to the coil, this will help make the coil last longer. Too much voltage going to the coil will overwork the coil, and it gets hot and they go out. I run MSD on a few things, kept burning up boxes and coils,,, put the resistor on, and had the same MSD box and coil for about 8 years now. Try it! Wont be disappointed! All you want from the MSD is the triple pulse spark pulse, and of course, 3000 rpm and up it goes back to a single pulse,, you can cut the voltage down and not notice much difference in performance. Keep the MSD in a cool dry place and keep the coil in a good place away from exccesive heat. Hope this helps.
If you mount the coil on a fender-well, away from the vibration and heat of the engine it will last a lot longer. Any coil that doesn't have oil in it should be epoxy impregnated. Each time a coil is loaded the wires in it move. You either cool it or cast it in epoxy. The number of windings in the primary side determine whether or not it needs a resistor. Some are wound for use with a resistor and others do not need a resistor. Coils made specifically for CD ignition systems have larger wire in the primary with fewer windings so that they saturate faster when the capacitors discharge into it.
Thanks for all the informative replies. Looks like I may still be mismatched. The new coil I picked up is the MSD Blaster 2 # 8203. Per their website, I should have picked up the 8202. [FONT=Verdana, Arial, Helvetica, sans-serif] Blaster 2 - PN 8203[/FONT] [FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=+1]Stock Applications[/SIZE][/FONT][FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=-1][/SIZE][/FONT][FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=-1][/SIZE][/FONT][FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=-1]The following Blaster 2 Coils are supplied with a 0.8 ohm ballast resistor and a terminal and boot to fit most applications. The ballast resistor must be used with stock Points Ignition and Mallory Unilite applications.[/SIZE][/FONT] [FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=-1] NOTE: These are the same coils as the other Blaster Coils, except they are supplied with a ballast resistor.[/SIZE][/FONT] [FONT=Verdana, Arial, Helvetica, sans-serif]Blaster 2 - PN 8202 [/FONT][FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=+1]MSD Ignition and Late Model Applications[/SIZE][/FONT][FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=-1][/SIZE][/FONT][FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=-1][/SIZE][/FONT][FONT=Verdana, Arial, Helvetica, sans-serif][SIZE=-1]The following Blaster Coils can be used in stock applications, but do not include a ballast resistor. When you are using an MSD Ignition Control, the Ignition is responsible for delivering the voltage to the coil so a ballast is not necessary.[/SIZE][/FONT]
Did you see the note on the 8203? I would bet that the ballast resistor is separate and you can install the coil without it.
