I've had two coils go bad and I think another one is on its way. The engine is a 318. Is there something that would cause failure or just my bad luck?
Make sure your coil is not an internally resisted coil, and look for any cracks or burn marks on the resistor
Excessive current applied to the coil for an extended period of time with the negative side grounded. With the engine started and running the voltage to the coil should be around 9 volts on a 12 volt system. 12 volts applied to start and it drops down with the key in the run position.Leaving the key on and with the points closed will burn out both coil and points.
I'm running the same setup on my off topic Chevy daily driver, and I'm eating coils. I think it's heat. I moved the coil from next to the distributer, to up high on the firewall the last time it quit. Once mine cools down, it starts back up and runs fine. The last coil did have oil on top of it. I installed the Petronix to fix the problem, I thought, because it did it with the stock points too. Dean
All coils are not the same, make sure you have the proper one for you're application and mount it as cool as you can away from engine heat.
cheap coils, heat and vibration.........I had a problem with my 390 with the old petronix 1, it would heat up the coils to break down, switched to points and problems went away. The petronix will make the coil run hotter then stock points but not overheat. I noticed on my flathead it likes the 1.5 ohm coil better (won't rev up to higher rpms with 4 ohm coil) and found through Gmc Bubba a USA coil company. http://andovercoils.com/ Gmc Bubba sells them.
I don't care for those Petronx units. F-ed my 235 all up. However, it could have totally been user error! Just sayin.
I used to have a Lucas Coil that I pulled off my BSA before venturing out on my Baja bash and replaced with a coil froma 6 cylinder chebby.I had no desire to be stuck in the middle of no where because some fella named lucas was still trying to get even for the war. I am with the heat and vibration crowd here. You can buy a cheap coil at "The Zone" or you can shop around and find a good quality coil and never have to worry about it.
you mounting it horizontal on top of the intake like stock mopar? Probably losing oil. Had similar issue with my 241 toasted two in very little run time. Just put the newest veritcle and off the engine to stop the shake/drain
x 2 what Magnus said. Don't mount coils horizontal. If there is a bubble of air inside the oil filled coil (which there probably is), mounting horizontal exposes some of the top side of the coil inside the casing and will cause it to heat up excessively (and burn up)... especially if you run the engine for long periods of time. I learned my lesson after getting stranded in SE Okla.
I seem to recall that the only coil I ever had to replace was one in a Mopar, it was mounted horizontally, the oil leaked out. But that was over 30 years ago.
I don't remember ever replacing a stock one. But after my accell burned up and had oil all over the neck I looked more closely and discovered that apparently there are epoxy filled ones that will work horizontal. I'd already picked up a msd in a rush so I put it on the firewall.
All these years and I never thought about that. I had one die on a 58 318 Plymouth. It wouldn't start when it was up to operating temps. Horizontally mounted on the intake.
I have actually replaced several over the years. All of them mounted upright on the intake. I never have replaced more than on on any given car. I always chocked it up to they just quit working.
I had 3 coils in a span of 1 year on my 29 Ford running a 2.5 AMC 4 banger with a special made Dizzy. All 3 came from NAPA, and I finally called Bubbas, in Indy. He sold me one and he told me it will be my last coil. So far he is right. He said that they don't have any good coil manufacturing companys any more. But he has a guy that makes them for him, and ain't had a problems since. The NAPA coils ran very hot, and were short lived. Iceman
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