In the 70’s, I had rented a small wood frame house with a one car wooden garage,white sheetrocked painted walls. I had a t bucket roadster,full race flathead with 12 volt ignition.I turned on the inside garage lite one morning and saw thousands of small black spots adorning the walls and ceiling; they were everywhere and were stuck like dots of black glue. Further inspection revealed the top of the coil had exploded and there was a large coil spring sticking out of the top of the coil.No, I did NOT leave the switch on, but a “short” must have occurred causing the coil to “blow its top” and I guess the coil oil got heated when it exploded and all those little black dots were liquid when it blew and dried into thousands of little black dots that stuck to the walls and the roof of the gloss white garage. I ended up having to repaint the white over the black dots, but it was like painting over thousands of bb’s like those used in a kids BB gun. It was terrible, something I had forgotten until reading about exploding coils.The landlord was understanding, but the walls and ceiling were “bumpy” with dried coil oil everywhere; there were thousands of little black dots.
old coils, way coil mounted, wiring problem, key on, etc - coil usually is something that most never think twice about - have had a battery explode upon just starting a stock car with no warning problems - diodes in alternators can fail with ignition off and cause fire
i left the key on had a petronic set up and a new hot coil it actually melted the coil right out of casing ....
I had a MEL in a dune buggy, and in my haste, didn't install a ballast resistor ahead of the coil. I managed to flip on the ignition toggle switch, without starting the engine. After it sat for a short while, I heard a "pop", it blew the bottom of the coil off, and sent it sailing, while still hanging on the fine copper wires. There was melted plastic sprayed all over. The buggy had 2 large 6 volts connected in series, plenty of battery power.
With the points closed your coils's primary winding acts nearly as a dead short. Check your points they may have welded shut.
While I was student teaching, my instructor had been asked to make a sparking device for a demonstration on flammability of various liquids. We discussed this with other instructors and got the idea that connecting an ignition coil to 110 would give a constant spark. Inductive reactance should limit the current flow since the direction of current flow is changing at 60 hertz. It sounded feasible and testing revealed a constant spark. However, current flow wasn't as limited as we theorized and oil started to spew out the end of the coil. It didn't blow, but the case bulged and it smelled terrible.
I haven't had one blow but have repaired a car that one blew on. Under the hood looked pretty much like what flatheadJohn47 Described on the shop walls. Someone had left the key on on that one though.
Mine didn´t completely blow apart, but it spilled the oil all over and wouldn´t produce a spark over 3000 rpm... Took a few hours until I found what´s wrong
A mechanic where I worked had a coil blow up on a fork truck as he was bent over the engine. His safety glasses prevented him from being blind. He recovered at home for a week with the burns to his face. Do not lean over coils or engine fans. (Blade took the bill off a fellows baseball cap in the pits one Friday night.)
Just reading this thread made me paranoid enough to go check to make sure I unscrewed my battery disconnect.
My best friend used to work for Echlin/Accel , I was at a party at his house and one of his co-workers was there, he had just returned from testifying at a law suit. Seems someone had bought a coil, installed it and it exploded. The defense pointed out the application for the coil was a 6 volt tractor, he installed it on a 12 volt vehicle with the opposite polarity.
I've done it twice. Once hot wiring a donated car and forgot to take the jumper wire off after it died. The second time on a MegaTech glass demonstration engine. Ran it out of fuel, the bell rang, didn't turn it off, went to lunch. That oil stinks.
It appears that the coil in question as mounted vertically, it is my understanding that the “ old” oil filled coils are supposed to be mounted horizontally so the oil can cool all of the windings....any of the ones you guys have seen explode been mounted horizontally?
60 hertz at the coil is equivalent to an otto cycle V8 running at 900 RPM. 4 sparks required per crankshaft rotation 900 RPM requires 3600 sparks per minute 3600 sparks per minute divided by 60 (seconds per minute) equals 60 sparks per second (equivalent to 60 HZ). Is it any wonder that points bounce and spark can become erratic at high RPM's?
Surprised it didn't blow that first. With the Igniter 2, btw, it's supposed to turn itself off if the key is left on.
Yup, me too. Left the ignition on inadvertently in our Chris Craft with a 283 and blew the coil to smithereens. Black all over the engine and inside the engine box.
Buddy of mine was telling me just last night that his battery was dead from leaving the ignition on, fortunately no coil explosion. But it got me wondering: Modern electronic ignitions have build it safety that turns them off if the key it left on. Might it be possible to design a gizmo for point systems that could also sense a load on the battery without any change (engine running or generator charging) over some time period and stop current flow?
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