'Smart' motorways

[geoberni]

I know it was common practice but I was never happy with coils mounted horizontally, old ones could be encouraged to leak...

On our MM our coil is vertical, mounted on the inner wing.

Yes, a lot of people probably don't realise that even 'old' coils usually have a screw in the top.
Unscrew that and you can see the oil level inside.
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Though I must admit I moved Basil's back to where his Coil was originally as a SII.
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[svenedin]

I’m back home now and had no trouble on the return journey with the old Pertronix resin filled coil which is horizontally mounted on the dynamo.

The failed "Remax" oil filled coil measures anywhere from 3.5 to 11.5 Ohms on the primary winding and it varies as I move the coil in orientation in my hand. The secondary winding is 9,000 Ohms and the reading is steady when I move the coil. My conclusion is that the connection to the primary winding is loose. I am not going to take the coil apart as I want my money back! When the car broke down, the primary windings were open circuit on continuity testing but I only had a small analogue multimeter with me in the car. Back home I have a high quality digital multimeter.

I will of course be asking for my money back!

Stephen

[geoberni]

That pretty much confirms what Claire Atkinson said...

[svenedin]

That pretty much confirms what Claire Atkinson said...

Yes. What I would like to know is what has changed with the oil filled coils that makes them so prone to breaking from vibration? The Series V has always mounted the coil on the dynamo and as far as I know, this was never considered an issue. There are old coils still in use that are decades old and still working perfectly and yet we hear over and over again about modern coils failing after minimal use. There must be something different internally.

Incidentally, my trip included a large section of the M25 with that concrete section road surface. This is just about the worst for vibration other than cobbles!

Stephen

[mike1864]

I’m back home now and had no trouble on the return journey with the old Pertronix resin filled coil which is horizontally mounted on the dynamo.

The failed "Remax" oil filled coil measures anywhere from 3.5 to 11.5 Ohms on the primary winding and it varies as I move the coil in orientation in my hand. The secondary winding is 9,000 Ohms and the reading is steady when I move the coil. My conclusion is that the connection to the primary winding is loose. I am not going to take the coil apart as I want my money back! When the car broke down, the primary windings were open circuit on continuity testing but I only had a small analogue multimeter with me in the car. Back home I have a high quality digital multimeter.

I will of course be asking for my money back!

Stephen

I agree it's likely a broken wire between the primary coil and the terminal, still just touching by a whisker. Mine eventually went intermittent for a mile before heat/vibration opened it up for good!
Analogue and digital multimeters deliver different test currents. And a fragile junction, perhaps with contaminants/oxidation, may not act as a pure resistance across the current range.It may even exhibit semiconductor characteristics.
If you were to give the case a whack, it may open it up for good. On the other hand, any small knock (eg in transit) might just close it up (for a few months?). The latter might result in Remax's return agents claiming No Fault Found. So I'd be tempted to video your testing now, as evidence.

[svenedin]

I’m back home now and had no trouble on the return journey with the old Pertronix resin filled coil which is horizontally mounted on the dynamo.

The failed "Remax" oil filled coil measures anywhere from 3.5 to 11.5 Ohms on the primary winding and it varies as I move the coil in orientation in my hand. The secondary winding is 9,000 Ohms and the reading is steady when I move the coil. My conclusion is that the connection to the primary winding is loose. I am not going to take the coil apart as I want my money back! When the car broke down, the primary windings were open circuit on continuity testing but I only had a small analogue multimeter with me in the car. Back home I have a high quality digital multimeter.

I will of course be asking for my money back!

Stephen

I agree it's likely a broken wire between the primary coil and the terminal, still just touching by a whisker. Mine eventually went intermittent for a mile before heat/vibration opened it up for good!
Analogue and digital multimeters deliver different test currents. And a fragile junction, perhaps with contaminants/oxidation, may not act as a pure resistance across the current range.It may even exhibit semiconductor characteristics.
If you were to give the case a whack, it may open it up for good. On the other hand, any small knock (eg in transit) might just close it up (for a few months?). The latter might result in Remax's return agents claiming No Fault Found. So I'd be tempted to video your testing now, as evidence.

Very good idea to video my testing! As you suggested, I just gave the coil a gentle knock with the palm of my hand and the primary resistance jumped to 60 Ohms.

Stephen

[geoberni]

That pretty much confirms what Claire Atkinson said...

Yes. What I would like to know is what has changed with the oil filled coils that makes them so prone to breaking from vibration? The Series V has always mounted the coil on the dynamo and as far as I know, this was never considered an issue. There are old coils still in use that are decades old and still working perfectly and yet we hear over and over again about modern coils failing after minimal use. There must be something different internally.

Incidentally, my trip included a large section of the M25 with that concrete section road surface. This is just about the worst for vibration other than cobbles!

Stephen

I think it's probably quality of materials and workmanship.
The original coils were from an era where generally speaking everything was 'over engineered' by modern standards.
It's a bit out of focus, but just look at the size of the solder joint in my broken one ....
Perhaps 3mm of contact and the barest minimum of actual solder.
That's fine in a small appliance, on a circuit board perhaps, and hopefully even fixed to a car bodywork, but directly mounted on an engine?

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I have 2 old coils in the garage, and whilst I am tempted to open one up for a comparison, I'll be damned if I'm going to destroy a serviceable vintage item just to prove a point
But I'll confidently say that something made before 1980 would have a far more substantial solder joint.
If I had produced a joint with such little solder on it when in training in the 70s, it would have been rejected.

[geoberni]

I agree it's likely a broken wire between the primary coil and the terminal, still just touching by a whisker. Mine eventually went intermittent for a mile before heat/vibration opened it up for good!
Analogue and digital multimeters deliver different test currents. And a fragile junction, perhaps with contaminants/oxidation, may not act as a pure resistance across the current range.It may even exhibit semiconductor characteristics.
If you were to give the case a whack, it may open it up for good. On the other hand, any small knock (eg in transit) might just close it up (for a few months?). The latter might result in Remax's return agents claiming No Fault Found. So I'd be tempted to video your testing now, as evidence.

I totally agree. It would likely need to be subject to a through stress test to reproduce the fault.
In brief, my 2 Coil related breakdowns were as follows:
When I brought Basil, I trailer-ed him home as it was a 70 mile trip.
A few local runs of a few miles, over a few days and he was fine.
I ventured a bit further and about 7 miles from home, having just entered the A1, he cut out.
RAC Guy diagnosed the 'Electronic Ign' and towed me home.
When back home he started fine and despite days of investigation and little trips totalling around 40 miles I just couldn't get him to fail.
So I replaced the electronic Ign module.
I was on my way down the A1 to the Nuffield Place event in 2018, about 30 miles from home and he did it again.
This time when towed home,fault was still there and I found the open circuit coil.
When I opened it up, some time later, it was not immediately obvious to the eye that the joint was broken.

[mike1864]

A similar story to mine. I broke down on the A3 and unsuccessfully tried all the usual fuel/ignition diagnostics. But after 30 minutes of tinkering it simply got better "all by iteslf".
Two years later it (presumably the same fault) went again in France. The primary measured a solid open circuit. So I replaced this three year old coil with the 30 year old original. The fault was a broken primary wire near the terminal; I've posted a picture in a previous thread.
Stephen, following my mention of semiconduction, you may find it measures differently with the leads reversed, ie this whisker contact is forming a partial diode.
An afterthought. I have seen some outlets (even a top department store) refund my damaged item, only to put it straight back on the shelf for the next customer.
In another incident an ITN colleague bought a VHS camera from a famous Tottenham Court Road shop, only to find it faulty. As an engineer, he opened it up, only to find a note from the previous purchaser next to the pcb : "If you find this note, I bet you too have found the faulty iris control. Take it back again, like I did. But complain even louder". Even more bizarrely, it was written by our colleague based in the ITN workshop.
Moral: Permanently mark the case of the faulty product as such (how can the supplier complain?). It might be you that buys it again!

[svenedin]

Advice received and taken! Thank you.

Stephen

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