Okay, had a pertronix flamethrower coil and ignitor ignition. Any how, I went to start the car today. Heard the loudest "explosion" I ever heard. Thought the carb backfired. What I found out was, the coil burst! Scared the hell out of me!! Anyways, replaced it with a stock coil from parts store. I removed the resistor wire long ago when I use to run HEI, so I still hiave the pink lead from coil to the fuse block on the firwall, no resistor. So new coil, car won't start. I check volts, key on at coil 12 volts. Then cranking it goes down to 9.28 volts. Ran a jumper from battery to coil. Car started immediatlly! So why would a 12 wire that started the car perfectly yesterday now drop to 9 volts today after the coil popped. What am I missing?
Ignition wiring has always confused me, but that replacement coil you have probably has a built in resistor. Did you ask the parts store you bought it from? A lot of them are coming with the resistor built in now. My flamethrower coil was a POS. Lots of people have trouble with them. Mine fried too. Got one with built in resistor from NAPA and just ran the same non resisted 12v to it that I rigged for the flamethrower.
Sounds like you are losing the voltage entirely in the run position. It may be getting voltage while cranking, but it loses it in run. BTW, the battery voltage will be dragged down by the load of the starter cranking the engine, at the coil, or right from the battery, the voltage will be the same while the engine is cranking. look at the wire going to the coil from the firewall. Make sure it isn't damaged.
In run, I have constant 12 volts. It when cranking it goes down. I understand that this will happen cause starter is taking load. I ran a jumoer lead to 12volts accessory on fuse box, same thing. But when I run the jumper from battery directly to coil full 12 on and cranking. Running 6 guage positive cable. Should it be a 4 guage? Would that affect it? But again, working yesterday, not today after coil went
Jason, If the engine starts after running a jumper wire from the battery to the + on the coil, the only reason I can think of is the existing wire leading to the coil + has a problem. Battery cable gauge is irrelevant I think.
I spoke with a tech from accel about what size resistor to run with the cylinder ignition coils. He said points and the coils like a .5 ohm resistor. After installing one I bought from altek( a computer store) I noticed the coil ran a lot cooler than before. Also I used the same size resistor on a friends ford that the ignition coil died before he installed a resistor. After we installed once again the coil ran cooler.
A stock coil will EXPLODE if it gets 12 volts too long this happened to me several years ago always run a balast risitor to the coil if using points or pertroincs stock coild can not handle 12 volts for long periods of time. IF you think you had it right well guess what you were wrong or it would not have blown up. I learned as well I just put a resitor between the coila and power never had a problem Ken
Dave Ray (IgnitionMan) says to run a porcelain ballast resistor, NAPA number ICR13 or equivalent, which is the correct resistor for the early 12 volt GM ignition systems, and, the stock coil is just fine as long as you run the spark plug gap where it should be, .032 to .035. He also says Pertronix sells two different types of coils, one is epoxy, the other is oil filled. You want the oil filled. Shake the coil, if it sounds like it is filled with liquid, that is the one you want to run. You also want to mount the coil with the wire end upwards, not on its side. Regards, Milton
I don't know about that Ken. You can use a stock GM points coil with an MSD 6 series CD ignition. An MSD 6A(L) applies about 450 volts to the coil. My Digital 6 applies over 500 volts to the coil. I believe the Pertronix ignition is meant to run with battery voltage, and the coil Jason was using was a Pertronix flamethrower coil.
Voltage to the coil while cranking should be 12 volts. Engine running (key in "on" postition) voltage should be approx 9. The 12 while in "crank" is coming from the starter, the 9 while "running" is coming through the igition switch, through a "resistance wire". You may want to check the starter output wire...
After reading these instructions, it seems the Pertronix is meant to run on full time battery voltage, like a GM HEI. http://www.pertronix.com/support/manuals/pdf/ignitor12vneg.pdf If you look around the internet though, you get a lot of contradictory information.o No:
Thats true but when using an MSD the box the points mearly trigger the coil and the voltage runs though it in pulses not on the positive side of the coil. the coil pulse is triggered by an impulse thats not the issue its the 12 volts to the posative side of the coil which a stock or a flame thrower can not handle a Pertronics does make a coil and an ignition set to use 12 volts but not all of them do. I sold these parts for many years and the constant power to the coil has nothing to do with the coil output to the wires. I may be wrong but in this case I am not :TU: I hope i explaned it correctly i am not real good at typing. I se every variation of these ignitons in my varied cars and I know what DOES NOT WORK and i know what works. for example you need 12 volts to an HEI and 8.3 or so to points or pertronics1 just the facts ken
Well, I just got off the phone with Pertronix. They want me to send the coil and module back to them for warranty. They are sending me new ones, and will reimburse me after they test them. They say their coils and modules requre 12 volts to run. They say, Like Larry said, that it is normal while cranking for the voltage to drop to 9 or 10, but they say that still should be enough voltage to make the motor kick. They suspect when the coil blew, it hurt the module. I ran a jumper from another 12v ignition on the fuse box to coil, did the same thing. The only way it starts is full 12 straight from the battery. Well see what happens.
Ken, in that case, what do I need. I ran the same exact set-up on my 350 for 5 years, never an issue. All I did was swap motor, did not change or mess with the wiring. This motor has run maybe 4 weeks. But no more resistor wire. Pertronix claim needs 12 volts. Where and how would I install a resistor? Oh, and the stock coil was bought temp. just to see if car started.
I understand what you are saying Ken, but in an MSD set up, whether triggered by points or magnetic pick up, the only connection to the coil positive and negative comes from the MSD box. The coil gets 450 volts, and with an engine running even at idle, it seems to me that would be nearly constant. I think Jason's coil was defective. It must have overheated.
.5 ohm ceramic resistor ... positive side. Try running with and with out one, your see the coil temp difference
I read throught that instruction and it is not spelled out as well as it should be uzzled: but in all 3 examples it shows using resitanace to the coil two ( 1 - 3 ) show an external resitor and the second one referes to a GM style resistor wire . if you read the instructions you can go back to points if needed you to thats one thing you can not do with 12 volts. This is not rocket seience but do it wrong and it may send your coil into orbit hahahaha. I would never have expected this either but after my explostion of a coil 3 years ago I know better now Ken
Yes, in the instructions, they tell you to bypass the ballast resistor by installing the wire "ahead" of the ballast resistor. I don't like Pertronix, I would never use one on any of my vehicles.
I understand your point of view but its incorrect the coil does not see any voltage running an MSD or Crane or Mallory it just produces the spark and the box get the voltage different set up. With the pertronics or points the power goes thu the points or pertronics to amplify the power and the coil can heat up with a box the box multiplies the spark and uses the coil differently Ken I wish i could explane better but its right
So if I dump the pertronix, what is the next best thing that wont cost me big$$$? It ran flawlessly on my 350. No resistor wire or ballastor all those years.
