I have an old accel coil that I'd like to use but it gets really hot after a few minutes of idling, there is no ballast resistor inline.

I just hooked up the crane xr700 so there's no more points, but the xr700 needs a ballast for the coil, and the coil seems to want less voltage judging by its external temperature.

I couldn't find the resistors listed in the crane instructions so I somehow found a '69 chrysler part number and got a 3.50 resistor from the auto parts store. I hook it up and it immediately begins to smoke and glow red, how hot are these things supposed to get? It does have a ceramic casing around the coil to absorb heat but man it glows like a toaster oven!

Only thing I can think right now is that a 69 chrysler runs on a 6v system? Maybe the 12v feeding it is making it extremely unhappy?

Can't I just get some resistors from radio shack and rig it up, how many watts would be enough?
--
'84 302 wagon '73 142

My now-gone 1979 245 had a ballast resistor. Means that a 240 1979 or older should have one - call a few boneyards or contact some dismantlers.

Good Luck,

Bob

:>)

Two tips:

a) Any coil, plus resitor, on series (one connecter to the other) would be 3 Omhs +/- 10% (2.7 to 3.3 Ohms). If you coil (alone) are on the range, dont need resistor. If it is less, add a resistor to totalize 3 Ohms.

b)Motorcicle coils dont work good on cars (overheats). Check your coil was made for car use.

Joaquin

PS.- On my previously mail I write about points, not your case, my excuses.

By example, see: http://www.bosch.com.br/br/autopecas/produtos/ignicao/dicas_bobina_ignicao.htm

Ah, and car resistors are made of nichrome wire due the high currents involved. Electronic resistors are for use on a very more light enviroment.
J.

Hi

Resistor usually goes hot red (it is a resistor, it transform electrical energy to heat, cheap way to reduce voltage). In my (car) case, a slight red on part of the resistor wire. The ceramic envelope would be protect the car from the heat.

But, every coil (designed for use with resistors) need a adequate resistor (measured on Ohms, from 0.4 to 6 or 8 ohms, depends on the coil). Check on the label of the coil, or on the wwweb about the right resistor value for your coil. By example, Bosch red coil made on Brazil need a 0.8 ohms resistor, the equivalent coil, made on Germany use a 0.6 ohms resistor. Coils without resistors (like the blue bosch coil or the originals on our volvos) usually have the resistor inside and not need additional resistors hanging around.

Any case, the coil heats a bit, but you would be able to touch it with your bare hand (engine off first, please).

Also, a little warning: installing a powefull coil in a car with points is a bad bussines; on few weeks the high current demands will be erode the points and you would be need to change points and condenser.

Due it, the Bosch blue coil is the usual replacement for amazon original coils. Any coil more powerfull need electronic ignition (Pertronics, Crane, Compufire, etc, etc, you name it) as a prerequisite.

Happy volving...and play carefull if (like many of us)you play mechanics on weekends (coil current have a punch equivalent to a electroshock medical machine).


Joaquin Novara
Rojo 121 Amazon
Lima - Peru

Older domestic cars use something in the range of 1 - 1.5 ohms in my experience. Perhaps you have a mis-boxed resistor. Try another for say, a 1971 Dodge Dart with the slant six. In series with the coil primary power from the ignition source it should work. There is even a starter bypass connection on the starter motor if you find the engine doesn't catch quickly while cranking.