Coil Failure(s)

[Dave6T4]

Is there any thing that can go wrong with a Mopar Performance electronic conversion system that can suddenly cause coil failures? I have had this system on my '67 R/T for over 30 years, and has always been very reliable. About 6 years ago, I had the coil fail and I replaced it (the engine just shut off). This summer, I had the top end of my engine apart for some repairs, and after getting the car on the road again, this 6-year-old coil failed after about 5 miles ( engine just shut off). I bought a new coil at my local parts supplier. The coil has a message printed on it that it requires an external resister (...as in Ballast Resister), so, I figure I have the right one. Lately, my car started running crappy (stalling at stoplights, stalling when shifting from neutral to drive, general running crappy at low speeds). I bought a spare new coil after buying the one on the car now, just as added insurance. Today, I put this new spare coil on, and everything is good again. I just took it for a 20 mile test drive, and the car drives just fine. The coil that just failed only had 180 miles on it. When I was putting my engine back together, I replaced my 30- year-old distributor with a low mileage M.P. unit that my friend had replaced in his car with an MSD system. This distributor works better than my old one. It starts quicker, the car runs smoother, and does not surge at cruise like my old one did (felt like the timing was moving around).
I can't really think that changing the distributor is now causing my car to eat coils, but 2 have failed since the change. I am hoping that I just got a faulty new coil. For now, I am just hanging close to home with the car to see what happens. New coil is Standard Products UC12. Any thoughts?

 

[Jerry Hall]

Check your ballast resistor for proper resistance on your system.

 

[Dave6T4]

Check your ballast resistor for proper resistance on your system.

I know this could be a dumb question, but does it matter what side of the resistor the wire to the coil comes off of? The reason I ask, the shop manual for my '67 appears to show it coming off the left side, while manual for my '64 shows the opposite. I have run both these cars this way for 30+ years. The ballast resistors are the full ceramic body ones, without the metal mounting strap, which I understand to be the proper ones for electronic ignition.

 

[Bee1971]

With your car running at engine idle in park

Measure voltage on the positive side of coil

Measure voltage on the positive side of coil at say around 1500 / 2500 RPMs also and report back

Thanx

I have had great luck with the Standard UC12 Canister Oil Filled Coil over the years

All types of different resistor values

What ECU/Ignition Module are you running also

 

[Dave6T4]

With your car running at engine idle in park

Measure voltage on the positive side of coil

Measure voltage on the positive side of coil at say around 1500 / 2500 RPMs also

Thanx

I have had great luck with the Standard UC12 Canister Oil Filled Coil over the years

All types of different resistor values

What ECU/Ignition Module are you running also

Orange MP ECU.

 

[qkcuda]

Watching Dave. I bought my old electronic ignition back when I sold the cuda. I am planning on installing it this winter. It has a much better advance curve it it.

 

[RJRENTON]

I know this could be a dumb question, but does it matter what side of the resistor the wire to the coil comes off of? The reason I ask, the shop manual for my '67 appears to show it coming off the right side, while manual for my '64 shows the opposite. I have run both these cars this way for 30+ years. The ballast resistors are the full ceramic body ones, without the metal mounting strap, which I understand to be the proper ones for electronic ignition.

In my experience, the solid filled ballast resistors usually made by Dale, have a tendency to overheat and prematurely fail. The old Mopar ballast resistors with the single metal mounting strap and are open in the back, are best....but your best source of information regarding ballast resistor ohm-age and which coil goes with which ballast resistor.....is @hallifaxhops on this site. The ballast resistor must be compatible with the coil and ECU.....in spite of what others think, do, or say. Just talking out loud......
BOB RENTON

 

[Sinitro]

In my opinion...
The majority of ignition problems is when different brand components are intermixed...
The coil, ballast resistor, ECU and distributor need to be compatible and matched with one another...

Just my $0.02...

 

[RJRENTON]

In my opinion...
The majority of ignition problems is when different brand components are intermixed...
The coil, ballast resistor, ECU and distributor need to be compatible and matched with one another...

Just my $0.02...

TRUE STATEMENT.....Too many people believe that it doesn't matter or they believe in my next door neighbor's cousin's sister's husband's brother-in-law's best buddy knows more than the people that invented the components.....but to each his own......and complain vehemently when the system fails......just saying....
BOB RENTON

 

[Dave6T4]

TRUE STATEMENT.....Too many people believe that it doesn't matter or they believe in my next door neighbor's cousin's sister's husband's brother-in-law's best buddy knows more than the people that invented the components.....but to each his own......and complain vehemently when the system fails......just saying....
BOB RENTON

Not complaining; just asking. As I said, the system had been working well for 30 years. Mopar Performance never included a coil as part of the conversion, nor a recommendation for a special coil. Parts supplier showed this coil for use with 440 up to 1978 (the final year of 440). By this time, these motors were using factory electronic ignition systems. I am hoping that I was merely supplied a defective coil. I guess time will tell.

 

[Geoff 2]

Something very strange going on. Coils often outlast the car....but you have had all these failures.
As far as which end of the bal res to connect, it can be either way, it makes no difference.
Check the charging voltage with engine running to make sure it is not excessive [14.5 or higher ].

 

[RJRENTON]

What part of the coil failed? Likely it would be the secondary or high voltage winding's, insulation failure allowing the high voltage to conduct to ground...resulting in a no spark condition. The coil is an autotransformer with windings placed over each other to affect a compact package, surrounded by a insulating fluid or an epoxy resin. Over time, the insulating materials can break down due to heat.and voltage transients. In electrical insulating systems, exceeding temperature limitations (which in this case) are not specified or disclosed nor what is the insulating fluid used. It is highly likely that the majority of the replacement coils are assembled in China, using unknown materials, including the coating of the wire's insulating materials...typically formvar, plus the individual insulating layers between turns, may be something less than fiberglass or craft paper.
Usually the user just replaces the failed part without determining what or why the coil failed. Upon dissection, the failure point would be evident...as burn or arc path markings to the laminations or case. What WOULD cause an overheating condition? High under hood ambient temps not withstanding, the use of an INCORRECT value ballast resistor (or it's elimination) will cause excessive coil heat, due to internal losses, or I2R loss or watts loss. All in search of more engine HP thru higher spark voltage.......just talking out loud.....
BOB RENTON

 

[Dave6T4]

What part of the coil failed? Likely it would be the secondary or high voltage winding's, insulation failure allowing the high voltage to conduct to ground...resulting in a no spark condition. The coil is an autotransformer with windings placed over each other to affect a compact package, surrounded by a insulating fluid or an epoxy resin. Over time, the insulating materials can break down due to heat.and voltage transients. In electrical insulating systems, exceeding temperature limitations (which in this case) are not specified or disclosed nor what is the insulating fluid used. It is highly likely that the majority of the replacement coils are assembled in China, using unknown materials, including the coating of the wire's insulating materials...typically formvar, plus the individual insulating layers between turns, may be something less than fiberglass or craft paper.
Usually the user just replaces the failed part without determining what or why the coil failed. Upon dissection, the failure point would be evident...as burn or arc path markings to the laminations or case. What WOULD cause an overheating condition? High under hood ambient temps not withstanding, the use of an INCORRECT value ballast resistor (or it's elimination) will cause excessive coil heat, due to internal losses, or I2R loss or watts loss. All in search of more engine HP thru higher spark voltage.......just talking out loud.....
BOB RENTON

Let's be clear here: I am not an automotive pathologist. The part that failed is the part that keeps my engine running. If you are looking to impress some one with all your jargon, I am NOT that guy.

 

[AR67GTX]

I have an old Ford, 2 old Plymouths and an old Vette so I hear all the forum horror stories on many forums. New coils seem to have a high failure rate and lack the quality of the originals, many of which still work. I’m sure some of it is incompatibility with ballast resisters and electronic distributors. Some have gone to epoxy filled coils, particularly if the coil lays on its side. But I’m not sure that has actually been a solution. I took a red MSD coil off a Hemi Road Runner we converted back to dual points a few weeks ago. The coil was wet on the bottom and leaking.

A good, original coil is often the best solution.

 

[RJRENTON]

Let's be clear here: I am not an automotive pathologist. The part that failed is the part that keeps my engine running. If you are looking to impress some one with all your jargon, I am NOT that guy.

We learn from our mistakes or failure analysis....beside the electrical systems ....if...you experienced a cam/lifter failure or a bearing failure, wouldn't you want to know WHY? .....or just replace the part and hope it does not occur again.......just asking.....
BOB RENTON

 

[Kern Dog]

.....just talking out loud.....
BOB RENTON

Everyone that I know talks out loud.
Do you mean "Thinking out loud" ??

 

[RJRENTON]

Everyone that I know talks out loud.
Do you mean "Thinking out loud" ??

View attachment 1369775

MAYBE......or it's a colloquial expression for expressing an opinion.....
BOB RENTON

 

[Bee1971]

Lets keep it simple

I asked for volts at the coil in POST #4

Start there with some numbers

And then the Orange Mopar ECU , could bee as simple as losing a ground source or the unit failing when in use after all these years

Hell , could bee a distributor pickup failing , or at least check the gap with a brass feeler also

 

[Dave6T4]

We learn from our mistakes or failure analysis....beside the electrical systems ....if...you experienced a cam/lifter failure or a bearing failure, wouldn't you want to know WHY? .....or just replace the part and hope it does not occur again.......just asking.....
BOB RENTON

Bob, I made that statement out of frustration, and I apologize for it. I returned the failed coil to my parts guy, and he replaced it. He said sometimes a bad part can get out there. We both agreed if my car eats another coil, something else is going on. I am going to do resistance test on my ballast, and test voltage of my charging system. As with a lot of owners of vintage cars, the least understood automotive system, for me, is the electrical system. I am getting better at it , but still have a ways to go.

 

[RJRENTON]

Bob, I made that statement out of frustration, and I apologize for it. I returned the failed coil to my parts guy, and he replaced it. He said sometimes a bad part can get out there. We both agreed if my car eats another coil, something else is going on. I am going to do resistance test on my ballast, and test voltage of my charging system. As with a lot of owners of vintage cars, the least understood automotive system, for me, is the electrical system. I am getting better at it , but still have a ways to go.

I understand.....perhaps I can help you troubleshoot your problem if it occurs again....
BOB RENTON