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Discussion Starter #1
Took my 64 /12 vert (289 2v) for its first drive yesterday after about 3 years of work. Rotisserie body work, rebuilt carb, and literally new or rebuilt everything else. The motor was not rebuilt as i had it rebuilt in the late 80s and had very little mileage on it.

As i am putting the care back together i am working very hard to have it look new And original (not completely concours, but close). I put on the autolite yellow top coil. Mounted it horizontally, on top of the intake manifold. New points, condenser. Timing adjusted pretty well with help from this forum.

yesterday we drove the car for about 10 minutes, brought it back to the driveway. idled in the driveway a bit. turned it off. Upon restarting, it was very rough at idle, then wouldnt run at all at idle, then not at all. First test drive ended by pushing the car back into the garage. Not the romantic vision i had to culminate over 3 years of work (cest la vie).

read several posts on the forum here including “Running rough when warm”. Which lead me to checking the coil.

We have been running the car in the garage for months as we were tuning it. No problem With the coil going bad Then.

tried to start the car today after it is cooled down, no luck. I put the old coil back on and it fired right up.

Questions:

1) could i have gotten a bum coil that failed after engine being at temp for awhile?
2) engine was running warm according to the gauge (new sender, new wiring harness) (near the right side of the scale). Should i be worrried that if the engine is running warm it will continue to ruin the coil? Never happened before we started the restoration work. But the coil was then mounted vertical. i put it horizontal to be correct.


As always, i appreciate the experience and expertise of the members. any help would be appreciated.
 

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I would venture you got a bad coil. Hard to say why it didn't fail you in the garage, maybe it just didn't get heat soaked quite as much as on the test drive. At least the problem surfaced in the driveway.
 

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I agree, you could certainly have gotten a bad coil. Standard Blue Streak would be a good option, if not the only option.

As far as running warm, are you sure it is running over 220-230? There are also a number of threads that suggest confirming your temp gauge reading with a mechanical gauge.
 

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I recently purchased a new temp. sending unit (Standard TS-24) and it read near the H when at operating temperature. The engine didn't seem to be running hot, so I installed the old sender and temp read normal.
 

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1967 Mustang Convertible
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To confirm the resistor wire to your coil is still in place after your restoration? The stock coil does not like a full 12V as that will make it run hotter.
 

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I always have a spare coil in the car. They don’t seem to last very long lately even with proper voltage.
 
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i think those yellow tops coils have been questionable for decades. hit or miss.

call Rock auto and get a 1.5 ohm Blue Streak. I paid about $14 a few yrs ago

make sure its 1.5 ohm and not the generic .85 ohm

STANDARD MOTOR PRODUCTS FD471 {Click Info Button for Alternate/OEM Part Numbers} (Heavy Duty) Blue Streak; Use with External Resistor
 

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Discussion Starter #8
thank you all. I put a new wiring harness in, so i (hate to say this) assume it has the built in resistor. I will follow all of the great advice, beginning with have a spare in the car.

Should i have any reason to be concerned with mounting it horizontally on top of the intake manifold? Wouldn’t think so since that is the way it was originally.

put in the new coil this morning. Drove it about 4 miles to the convertible top guy for a new top. Temperature gauge stayed put just a little bit left of middle. No problem. Fun to drive the care after 3 years in the making!
 

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Oil filled coils should be mounted vertically regardless of how Ford did it. An epoxy coil such as the one Ford used in the mid-80's is the reliable alternative to the oil coil.
 

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Discussion Starter #10
Thank you Awhtx. I continue to learn about all of the nuances on this car. As i mentioned earlier, i am not building a perfectly concours correct car, but am trying to do as much as possible to make the care as it rolled out of the showroom. Given the coil was mounted horizontally on top of the intake manifold, did all cars end up burning out coils? How do the concours restoration folks address this?
 

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Coils mounted horizontally, like the engineers originally specified, have been known to last decades. New ones can be bad out-of-the-box or fail soon. Normal engine temperatures shouldn't cause a coil to fail prematurely. Concours folks know how to keep a spare Scott Drake coil in the trunk. Make sure your coil is powered through the resistor wire in the ignition circuit. A voltmeter should read something around 9 volts at the positive terminal of the coil while the engine is running. If it reads the full voltage of the car while the engine is running, an original replacement coil will fail.
 

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Discussion Starter #12
Thank you Cougar70. I will measure it as soon as i get the car back, I drove it over to the shop to have the convertible top put on with a coil from advance auto parts. 3 mile drive, no problems.....

As always thank you all.
 
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