I’m wondering if my coil is going bad

[shew01]

I bought my 1931 Victoria a little over a year ago. It has always started extremely well, usually with one touch of the starter button. As I learn more about Model As, I’ve been replacing worn parts, ordering spare parts, and sometimes swapping out known good parts that came with the car so that I would serviceable parts for spares.

About six weeks or so ago, I swapped out the condenser for a new one. The engine continued to start and run fine.

About two weeks ago, I swapped out the Ford script coil for an oil filled coil that the previous owner sold me with some other spare parts. At the time of car and spare parts sale, I didn’t know that a coil could could be tar filled, expiry filled, or oil filled. I mounted the oil filled coil upside down like the original, and, presumably, there is an air bubble at the top of the coil on its inside. The wiring would not reach far enough to mount the coil right side up.

I’ve driven the car about 300 miles or so, and, yesterday, I noticed the car was hard to start after the engine got warm. I also noticed the coil got pretty warm to the touch. I could still place my hand on it without getting burned, but it seemed pretty hot to me. It was about 72 degrees outside on a nice fall day. The engine has a thermostat that keeps the coolant around 170 degrees.

How warm should a coil get? (I didn’t have my temperature gun with me to check it.)

Does it sound like this “new to me” coil is failing?


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[Ray64]

Put the old coil back on and try it

[mike657894]

oil filled coils are meant to be run right side up.

[McMimmcs]

Originally Posted by Ray64

Put the old coil back on and try it

Good, sound advice !

[Patrick L.]

Yep, what Ray said. Or when its warm/hot/acting up, check with the ohm meter.

[1931 flamingo]

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"The wiring would not reach far enough to mount the coil right side up." Get a longer wire........


Paul in CT

[Purdy Swoft]

I agree with Paul .

[shew01]

Originally Posted by 1931 flamingo

"The wiring would not reach far enough to mount the coil right side up." Get a longer wire........


Paul in CT

That would be wireS. Nothing (the coil wire nor the wires for the coil terminals) would reach. ;-)

I’m not firmly convinced I have a coil problem yet, which is why I posted. I don’t want to keep changing a bunch of stuff quite yet. I’ll probably put the old coil back on after some more road time.

I was hoping to get some feedback about how a coil acts when it is potentially beginning to fail.

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[mass A man]

If you decide to get a new coil, try the Pertronix 6 volt, epoxy filled "Flame Thrower" coil. Got mine from Summit Racing, very happy with it too! The part # for that particular coil is:40111. It is the 1.5 Ohm coil for the Model A if you still run 6 volts. They do make one similar for ones that changed over to 12 V.

[duke36]

Have you tested the readings across the terminals ? Different values (with or without internal or external resistors) for 12 volt vs. 6 volt

[Synchro909]

Originally Posted by mass A man

If you decide to get a new coil, try the Pertronix 6 volt, epoxy filled "Flame Thrower" coil. Got mine from Summit Racing, very happy with it too! The part # for that particular coil is:40111. It is the 1.5 Ohm coil for the Model A if you still run 6 volts. They do make one similar for ones that changed over to 12 V.

I've had 2 of those coils fail on me in short time. Not a good option, IMO.
I run any old oil filled coil now but mounted with terminals up. As has been said, you would need to get a longer HT lead but I've had no trouble since.

[Purdy Swoft]

My Pertronix flame thrower coil is still holding up good after 14 years on my roadster . I run the part number 40611 epoxy 3.0 ohm version on 12 volts . I get instant starts ann more power that can be felt . The six volt version may not perform the same as the 12 volt version .

[1crosscut]

[QUOTE=shew01;1950614]That would be wireS. Nothing (the coil wire nor the wires for the coil terminals) would reach. ;-)

I’m not firmly convinced I have a coil problem yet, which is why I posted. I don’t want to keep changing a bunch of stuff quite yet. I’ll probably put the old coil back on after some more road time.

I was hoping to get some feedback about how a coil acts when it is potentially beginning to fail.

That indeed would be good feedback to have.

[daveymc29]

When failing coil happened to me I felt a definite lack of power. The coil was hot to the touch and eventually I noticed that it got quite hot to the touch, burn fingers hot , and the oil began to leak out of it. Barely got the car home from a three block run that time. Another instance I had a foam fillled A(EApoxy) that I thought had an internal resistor. It did not and it also failed to last for a short drive of about three miles before there was a decided lack of power and a few miss fires. Next morning the car was cold and started right up and I took off for half a block. It quit running and the coil blew a plug out of the bottom of it (opposite end from the ht lead) and all the epoxy foam came out and ran down my fire wall. That one was my fault for not installing a resistor. They definitely will loose power as they heat and usually will work okay for a minute or two until they overheat. Just enough to get you a good walk from home when the car will die. If the coil is oil filled you can shake it by your ear and even I can hear the fluid sloshing around inside. If so mount it with the HT lead up and use longer wires to make it function. I'm told not all oil filled will fail, but most will. Originals were filled full with a tar like substance and don't mind being HT lead down.

[jm29henry]

Have you checked your point gap ? Maybe they are wearing ? Just a thought and easy to check!!!

[shew01]

Originally Posted by mass A man

If you decide to get a new coil, try the Pertronix 6 volt, epoxy filled "Flame Thrower" coil. Got mine from Summit Racing, very happy with it too! The part # for that particular coil is:40111. It is the 1.5 Ohm coil for the Model A if you still run 6 volts. They do make one similar for ones that changed over to 12 V.

I have one more spare coil. It’s an oil filled one that I bought new from a Model A vendor before I learned the differences between coils. I plan to try it out too when I get a chance. I still have the oil filled coil (that I originally posted about) in the car at the moment.

Yesterday, the car was hard to start twice (on two legs of a trip) after it was driven 10 miles or so for each leg of the trip. So, the engine was hot when it didn’t want to start. However, it started fine at the end of our trip in our garage with the engine hot.

This evening, the car was hard to start cold.


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[shew01]

Originally Posted by duke36

Have you tested the readings across the terminals ? Different values (with or without internal or external resistors) for 12 volt vs. 6 volt

No, I have not. Can this be tested with the coil in place on the firewall? If so, do I need to disconnect the wires on the terminals? Or, can I leave those in place?


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[shew01]

Originally Posted by daveymc29

When failing coil happened to me I felt a definite lack of power. The coil was hot to the touch and eventually I noticed that it got quite hot to the touch, burn fingers hot , and the oil began to leak out of it. Barely got the car home from a three block run that time. Another instance I had a foam fillled A(EApoxy) that I thought had an internal resistor. It did not and it also failed to last for a short drive of about three miles before there was a decided lack of power and a few miss fires. Next morning the car was cold and started right up and I took off for half a block. It quit running and the coil blew a plug out of the bottom of it (opposite end from the ht lead) and all the epoxy foam came out and ran down my fire wall. That one was my fault for not installing a resistor. They definitely will loose power as they heat and usually will work okay for a minute or two until they overheat. Just enough to get you a good walk from home when the car will die. If the coil is oil filled you can shake it by your ear and even I can hear the fluid sloshing around inside. If so mount it with the HT lead up and use longer wires to make it function. I'm told not all oil filled will fail, but most will. Originals were filled full with a tar like substance and don't mind being HT lead down.

My oil filled coil is definitely getting warm, but I don’t know if it’s “out of spec” (for lack of a better phrase) from a temperature perspective.

So far, I have not noticed a lack of power.

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[shew01]

Originally Posted by jm29henry

Have you checked your point gap ? Maybe they are wearing ? Just a thought and easy to check!!!

I reset the point gap about a week ago. I’ve driven the car about 300 miles since then without an issue (until I swapped out the coil later).

So, there is a correlation with hard starts after swapping out the coil. But, that doesn’t necessarily mean that the coil is the culprit.


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[shew01]

Originally Posted by Synchro909

I've had 2 of those coils fail on me in short time. Not a good option, IMO.
I run any old oil filled coil now but mounted with terminals up. As has been said, you would need to get a longer HT lead but I've had no trouble since.

Were your leads to the coil terminals long enough to reach the terminals with the coil installed right-side-up? Or, did you have to add some wire to lengthen them?

There is no apparent way for me to stretch my wires to reach the coil terminals if I turn the coil right-side-up.


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[katy]

Have you tested the readings across the terminals ?

do I need to disconnect the wires on the terminals?

You'll have to disconnect at least one of the low tension wires.

There is no apparent way for me to stretch my wires to reach the coil terminals if I turn the coil right-side-up.

For a trial run, get a piece of stranded wire (8 - 10 inches long)and put a ring terminal on each end, use a small machine screw (#6 or #8) to connect one end of the wire to the wire that came off the coil, tape it up. put the other end on the coil, simples.

[shew01]

I removed the oil filled coil this afternoon, and the ohms tested within spec cold. It’s rainy today; so, I didn’t take the car out to get it hot, and I didn’t want idle it a lot in the garage.

While I was under the hood, I swapped in my brand new oil filled coil to see how it will work. The car seemed to start okay cold (but the previous oil filled coil usually started okay cold too), and I plan to drive it a few days after the rain stops. If I’m going to have trouble with this coil, I’d like to have local car trouble, rather than out of town car trouble. If this coil gives problems, I can revert back to my original (to me) Ford script coil.

I plan to buy an epoxy filled coil next time.


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[shew01]

Originally Posted by katy

You'll have to disconnect at least one of the low tension wires.



For a trial run, get a piece of stranded wire (8 - 10 inches long)and put a ring terminal on each end, use a small machine screw (#6 or #8) to connect one end of the wire to the wire that came off the coil, tape it up. put the other end on the coil, simples.

Thanks for the idea. I’ll keep this in mind.


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[shew01]

Over the last several days, the car has gotten harder and harder to start, to the point that it would not start today. This afternoon, I put the original (to me) Ford script coil back in the car, and it would not start. I reinstalled my original (to me) condenser, and the car would not start. It didn’t look like I was getting much spark; so, I checked the points, and the point gap was off from where I set it a few weeks ago. I reset the point gap, and the car started great.

The lock screw (for lack of a better term) seemed to be tight on the point set screw. I wouldn’t think the rub block would have worn that much in 300 miles or so.

Does anyone have any ideas about why point gap would appear to “slip?”


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[Patrick L.]

Originally Posted by shew01

Over the last several days, the car has gotten harder and harder to start, to the point that it would not start today. This afternoon, I put the original (to me) Ford script coil back in the car, and it would not start. I reinstalled my original (to me) condenser, and the car would not start. It didn’t look like I was getting much spark; so, I checked the points, and the point gap was off from where I set it a few weeks ago. I reset the point gap, and the car started great.

The lock screw (for lack of a better term) seemed to be tight on the point set screw. I wouldn’t think the rub block would have worn that much in 300 miles or so.

Does anyone have any ideas about why point gap would appear to “slip?”


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It probably didn't slip, it probably wore. It depends on the quality of the points and whether the block was lubed. Greasing it correctly is very important.

[shew01]

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Originally Posted by Patrick L.

It probably didn't slip, it probably wore. It depends on the quality of the points and whether the block was lubed. Greasing it correctly is very important.

I definitely keep it greased.


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[shew01]

Originally Posted by Patrick L.

It probably didn't slip, it probably wore. It depends on the quality of the points and whether the block was lubed. Greasing it correctly is very important.

Patrick,

I’ve been using Lubricam from the previous owner, but the tube looks a bit old. Would Lubricam lose its strength over time?


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[shew01]

Originally Posted by mass A man

If you decide to get a new coil, try the Pertronix 6 volt, epoxy filled "Flame Thrower" coil. Got mine from Summit Racing, very happy with it too! The part # for that particular coil is:40111. It is the 1.5 Ohm coil for the Model A if you still run 6 volts. They do make one similar for ones that changed over to 12 V.

Thanks for the part number. I saved it for a later purchase.


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[shew01]

Originally Posted by Synchro909

I've had 2 of those coils fail on me in short time. Not a good option, IMO.
I run any old oil filled coil now but mounted with terminals up. As has been said, you would need to get a longer HT lead but I've had no trouble since.

Hmmm... it seems that folks either love or hate the Pertronix coils. I wonder why folks have such different experiences with them.


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[shew01]

Originally Posted by jm29henry

Have you checked your point gap ? Maybe they are wearing ? Just a thought and easy to check!!!

When I responded to you several days ago, I had only driven 300 miles or so after setting the point gap with this tool.

https://www.brattons.com/quick-set-p...ting-tool.html

I had no idea point gap could change that much that quick, and I had no idea how much it could affect the way a car would run. It eventually got to the place that the car would not start at all. When I reset the point gap, the car started like it used to start—usually on the first crank.


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[Patrick L.]

Originally Posted by shew01

Patrick,

I’ve been using Lubricam from the previous owner, but the tube looks a bit old. Would Lubricam lose its strength over time?


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The quality of points today varies greatly, the expensive ones are usually the best. The rubbing block wears quite quickly at first. The lube needs to get between the cam lobe and rubbing block. The wear should slow once readjusted.
Point gap controls coil saturation time as well as changing timing.

[Ruth]

Originally Posted by Patrick L.

The rubbing block wears quite quickly at first. The lube needs to get between the cam lobe and rubbing block. The wear should slow once readjusted.

I call that the 'Break in period' and I check the point gap often when new points are first installed. Once 'Broken in' they don't wear as fast. I don't know why this is.

As Patrick says keep them properly lubed.

[Patrick L.]

Originally Posted by Ruth

I call that the 'Break in period' and I check the point gap often when new points are first installed. Once 'Broken in' they don't wear as fast. I don't know why this is.

As Patrick says keep them properly lubed.

The cam and rubbing block just need to get used to each other. They'll wear into each other after awhile.

[shew01]

Originally Posted by Patrick L.

The cam and rubbing block just need to get used to each other. They'll wear into each other after awhile.

These are not new points. They have been in the car for over a year and several thousand miles, which is why I was surprised at the gap “movement” over the last 300 miles or so.

[shew01]

Originally Posted by shew01

Patrick,

I’ve been using Lubricam from the previous owner, but the tube looks a bit old. Would Lubricam lose its strength over time?


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I greased the distributor cam again today, using Vaseline. I don’t know if it that will wear any better or not.

Would a different type of grease be better? Maybe white lithium grease?

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[Patrick L.]

I didn't think we were aware the points had been around for awhile.

Maybe something has 'slipped' or maybe the points are just poor quality.

Vaseline has been used for decades, its been a multi-purpose lubricant for many many things.

[Flathead]

After tightening the adjustment screw see if the point contact itself is tight. The adjustment block is die cast metal and will stretch causing the contact to not be secure but the lock screw will be tight because the block has deformed and bottoms out.

[katy]

Does anyone have any ideas about why point gap would appear to “slip?”

Check the distributor cam's surface, it should be extremely smooth, if it's the least bit rough the point's rubbing block will wear down quite rapidly.

I had this a couple of years ago, I had put a new "B" cam in the distributor and never thought to check it's surface. The point's rubbing block wore down in less than 50 miles. I took the cam out and polished it w/crocus cloth, it's been fine since then.