Toasted Second Coil - Extremely Frustrated

jrhaelig

jrhaelig

Senior Member
I haven't even gotten my darn truck to make more than a sputter and I have toasted another coil.

I mounted my Bubba's distributor today. He also tested the coil & condensor - they were OK.

Got a sputter, then battery died. Put the charger on. 6 volts. I did notice after the fact that I charged with the ignition switch on.

Went back a few hours later. Cranked it 3 or 4 times and smelled the coil cooking off.

I am tired of hitting failures & obstacles and am beginning to think about cashing out. Progress is fun. Failure is not.
 
jrhaelig....hang in there. My rear brakes on my '32 hydraulic conversion are giving me fits. The combo of shoes/hubs/drums giving me trouble but I believe it is all due to the damned offshore wheel cylinders. Then I find out my stock front axle dropped 4" by Joe was on the wrong way. I have just now pulled everything back apart to switch it around. One step foward, five back.

BTW, cool looking truck!
 
Check all polarity. Also,check to be sure your ignition switch really does turn "off". Don't know your situation but I'd recommend disconnecting the wiring harness and running a separate wire to the coil from the battery to help you locate the "ghosts". At the risk of asking a silly question, 6 volt coil? Totally 6 volt system? Stock ignition switch? Using a resistor with the coil? Hang in there. This can be figured out.
 
George -

It is a new battery (cheapo, but new). Sounds like charging battery only with no leads connected is best then......


Henry -

It is an all original system. 6 volts all around. I have noted that starter button turns it over with the ignition switch in either the "on" or "off" position. New condenser - Echlin FA49 as recommended here.

Could it be from the charging with the ignition switch on? I don't think I over-cranked - but what is your definition of over cranking?
 
Charging with the ignition switch on will take out the coil if the points were closed. There is a high probability they were closed.
The starter button will turn the engine with the ignition switch in the on or off position.
 
Have you tested the voltage going to your coil ? There is a resister that cuts the voltage going to the coil . When I bought my 39 Tudor the previous owner had wired up the headlight circuit through the resister and the main power to the coil direct . I killed two coils within days of each other while tracing down my dim light problem. After switching the wires I have had no coil issues and bright lights . Just a thought ?
Don't give up . When you start driving your truck you will be having so much fun you will forget all about the trouble shooting issues .
 
which distributor....coil??....if one of the helmet ones, maybe get the adaptor that allows you to use a regular coil??...just a thot....sorry about your troubles, but hang in there....Mike
 
I have been guilty of leaving my ignition on for an extended period and toasted my coil.
It happened after I was working on the car and became distracted.
Don't give up.
 
John - Based on what's been presented, I'd bet that charging the battery with the ignition switch "on" is the likely culprit.

On your next attempt, if you take the input wire to the coil off and run a jumper from the battery (neg. terminal) to the coil, you'll bypass any possible problems in the wiring harness. A long piece of #16 wire with a clip at each end ought to work well.

If the car starts, you'll know the problem is in the wiring harness - and then troubleshooting on the wiring harness can begin.

Skip Haney does a great job of rebuilding old coils. Good Luck!
 
Mike in AZ said:
which distributor....coil??....if one of the helmet ones, maybe get the adaptor that allows you to use a regular coil??...just a thot....sorry about your troubles, but hang in there....Mike
Click to expand...

Mike, two thoughts on that:
One, the coil is not the problem: Going with a "regular" coil won't fix the problem.
Two, those silly looking adapters are so embarrassing, a guy would have to leave his hood closed at the Thursday Night Drive In!
 
I thought that leaving the ignition on without the car running would burn the points. I would bet you have a missing or bad resitor in the circuit.
 
jr The only way to melt a coil is to leave the ignition switch on. If left on there is a 50/50 chance it will melt. The deciding factor is if the points are open or closed. Open there is no voltage to the coil and no proplems will occur. Points closed the coil becomes a resistor similar to the heating wires in a toaster. In a lot of cases the battery will run down before the coil is completly destoyed, the voltage also drops as the battery gets weaker and only the tar will melt and not have enough heat to burn the insulting varnish off the winding wires. The tar will solidify with no damage to the coil. There is also a resistor in the NEG hot wire between the ignition switch and the coil. This drops the voltage to about 4 volts WHEN THE POINTS ARE CLOSED. When the points are open the is no resistance from the coil and the coil wire will read close to battery voltage of around 6 volts. I don't think you would burn the coil up running without a resitor, it may melt the tar but I don't think it would destroy it. You don't want to run with out a resistor for over 10 or 15 minutes. It takes 10 minutes for the tar to melt and the coil insulation to start to burn. The size of the points and the point material are larger and better than a 25 amp industrial relay which will carry 25 amps for days. The points don't burn from a shorted coil, they arc and pit when they make and break drawing an arc. The best prevention is a heavy duty battery disconnect turned off when the engine is shut down. There will be no voltage to melt the coil or a fire from a shorted wire. If a battery charger is on when the ignition switch is left on there is a good chance a fire could start. G.M.
 
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ford38v8...just throwing a suggestion out there....don't know how much he's spending on original coils, etc....and heck, i just came from Goodguys and saw a few flatheads in some nice cars that had that adaptor....if it can help him get his ride running and he can enjoy it, then what the heck....then he can get himself an original coil in the future....just tossing the suggestion....Mike
 
Not a bad idea, Mike.

Leaving the ignition on whether charging or not will damage the coil if the points are closed.

Did it myself, as have many other people I bet.

The early cars hot having a generator charging light doesn't help.

Mart.
 
It has been said that if you take a 12 volt coil and wire it backward it works.
If you have a round coil, think you would be better with and old 6 volt one, the dirtyer the better.
If you are working on car with engine not running pull power wire from coil.
When starting remember to put back on.
 
I agree with G. M. I have 3 old cars & battery shutoffs on all of them, they also are very nice to have when you are working on the car as you can disconnect the battery with a flick of a switch & also good for storage I have 2 good ones & a cheapie (buy the good ones).
Gary.
 
Any car with points and coil will suffer damage if ign switch is left on! That includes tractors too.
 
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