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TR4/4A Fried Ignition Coil

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Cokerair

Cokerair

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1963 TR4 converted a couple of years ago to NEGATIVE Ground. I believe it is a non-ballasted coil.
So... The car ran GREAT for my last trip a couple of weeks ago for 2 hours going and 2 hours returning with no hiccups. Preparing to go on errands today (Have not driven her for over a week), it will not start.
Checked battery: dead and will NOT charge.
Bought new battery, engine turns over, but will not start.
Looked at distributor and while points are OK, the connectors for the points and condenser were very loose. Unusual... As well, there was a burn mark on the inside of the cap next to the loose screw. The rotor was somewhat burned at the tip where it spins to make the electrical contacts. Since I keep replacement Cap, Rotor, Points and Condenser with the car, I replaced them.
That's when I noticed the coil was fried. literally fried.
WHAT have I done wrong? Was the coil misconnected? How did it start and run? Could a mis-boxed ballasted coil be the culprit?
I'm stumped.

TR4 Coil A 11-1-23.jpg
TR4 Coil B 11-1-23.jpg
 
Probably a constant flow of current thru the ignition system including the coil until the battery drained....kinda like what happens if the ignition key is left ON and the points just happen to be closed (touching).
 
On the bright side , a Lucas coil only has so many sparks from the factory, might have been
running low any way. ( Has happened to me)
Mad dog
 
I remember many years ago in auto shop, the instructor would say, a car starts on 12 volts and runs on 6 volts. Maybe the coil did need a resister wirer. I had a coil that looked like that on the top and lasted a week. I would look around for a different brand coil. You might be able to get one from a local auto parts or racing shop. I did some years back for 1967 tr4.

steve
 
Solutions (and insults) offered on "The Triumph Experience". I will try the most logical solution of a new coil mated to Pertronix in place of the points/condenser.
 
If the same event happens, you'll be out of a coil and the PERTRONIX Ignitor.
You need to find out why what caused this and fix it; not just replace the ruined stuff.
The Pertronix will not tolerate even a few seconds with the ignition on and the engine not running.
 
Last edited:
Ignitor II or Ignitor III absolutely require a matched Pertronix coil. Using a Lucas (or any other brand) with an Ig2 or Ig3 will fry one or the other and possibly both. If you're running an Ig2 or Ig3 module, that is likely the reason why your coil ended up like that.

Ignitor I, on the other hand, was designed to work with a stock (ballasted) coil. If you're running an Ig1, then find the cause and fix it first.
 
Buy a 3 ohm coil because they are already set up for the lower voltage. That is what a tr3 uses and your car is the same. Naturally replace the points and condenser. The same auto shop instructor (1969) stated the condenser absorbs static electrons and has more to do will the coil and condenser hooked together --than the points. The points just make and break the circuit for the coil and condenser.

Perhaps the problem you had was the loose connection on the points and the coil was cutting in and out more than usual from when the points opened and closed causing the coil to heat up and die.

steve
 
Some aftermarket coils require a ballast resistor to reduce the current through the coil. It's possible that your coil should have had a resistor, but did not. That will create a great spark, but the coil will run correspondingly hot. That could have been your case.

Also, do a search on petronix before making the jump. You will find there are at least double the number of threads with petronix problems as there are with the stock points. Just something to think about. Plus, when the petro dies, you are out of luck unless you brought a spare. Points can usually be milked home.

Sorry about the insults on the other forum. That's why I quit visiting there...
 
The real problem in fitting up petronix is you must use resistance wires. OK so you install
new wires on your cap. BUT the screw has a pointed end that usually severs the delicate
material that carries the spark. Not good. Blunting the ends of the screws makes a big difference.
BUT Loctite the screws ,as they are now wont to come lose, destroying the distributor.
In my perfect world ,somebody would sell wires( with metal ends) that FIT into the Lucas cap.
Mad dog
 
Iā€™ve had a Pertronix in my car for over 20 years. Never had a problem. Iā€™m aware of not leaving the ignition on without the engine running. I confess to leaving the key in the run position a couple of times for 15-20 seconds but itā€™s never burned out.
Given the choice, Iā€™ll stick with the Pertronix.
 
Been offline for awhile, so catching up checking out old posts.

Steve in post #8 nailed the cause of the original problem. I spent 35 years as an electrician, with a large part of those years spent as a troubleshooter. I can definitely tell you that 99% of all electrical problems (and fires) are caused by loose connections. The analogy I usually use for customers or new apprentices is that of a spark plug, which is really just an intentional loose connection when you think about it. Electrical current jumping a gap of any kind (including a loose connection) will produce heat, which will damage the conductor, thus making the gap larger, which then produces more heat. Amazing how much damage a loose connection can cause, even at relatively low voltages. Anyone who has blown a chunk out of a solid steel wrench that got crossed up with a battery has seen what kind of damage a mere 12 volts can do.

Long story short, just replace all the damaged parts with good stock parts and pay attention to the connections and you will have many trouble free miles

Tom
 
TR Tom said:
Long story short, just replace all the damaged parts with good stock parts and pay attention to the connections and you will have many trouble free miles
Click to expand...

Thank you, Tom!
As soon as the "loose connector/screw" comment was read, it was the "Ah HA!" moment. Loose means resistance. Resistance means heat.
 
I love Petronix too, but it is a great idea to mount up new points and a condenser on an old
base plate to have (in a zip lock bag) ready to go in emergency. Just having it ready can keep
the spark demons away (they feed on Lucas bits)
Mad dog
 
I echo Elliottā€™s report with exactly the same history in my TR3A. Never had a problem with the Pertronix except when I replaced my C39 Generator with a rebuilt generator that was positive ground (dumb move). Only managed to drive a half mile before she died. I am now running an Alternator which has solved any electrical issues I might have been having.
Frank Dā€¦..
 
Funny how everyone has an opinion on the Pertronix Conversions. FWIW hereā€™s my experiences.

My wifeā€™s DD 65 Mustang has had a Pertronix for over 20 years with absolutely no problems.
My 65 Chevy truck also had one for many years before I swapped in an HEI. Again, no problem, just put in the HEI cuz it needed a new distributor.
Last car to convert was the 65 TR4. Went with both the kit and the coil this time, other cars just used the stock coil. Over the course of about two years had two coils and two modules fail. Everything was running fine each time, until it wasnā€™t. As I recall was months between ā€œeventsā€. Each time I sent back fried parts as they always said they could tell the cause of failure forensically. Each time I was promptly sent new parts with no explanation of any kind.

Needless to say after four strikes I went back to points and have had absolutely no problems in many miles since. I did upgrade to heavy duty Standard brand points/condenser and a blue Bosch coil. Put Standard points next to current Lucas offering and youā€™ll see why I made the change.

Anyway, thatā€˜s my story. Ask ten people their opinion on Pertronix and youā€™ll probably get eleven different opinions, so obviously no right answer. Whatever you choose, hope it gets that car back on the road and keeps it there where it belongs

Tom
 
Points are like a generator, they wear out over time and need to be refreshed. I have always been
happy with either in "good kit".
My old 63 would get the generator off for a clean /lube every 10k .It never failed in all the years I had
her. (Did break a front plate once). The points (Lucas!) were to me, coming up in the 60's , just like changing oil
something you just did on occasion. Part of life and the Zen of motor maintenance .
Mad dog
 
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