It's never the coil?

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youngb506
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It's never the coil?

Postby youngb506 » Fri Jan 26, 2018 7:51 pm

I've been having a few mysterious issues recently with my 1957 not always starting or sometimes cutting out. Complete stop five miles into the journey this morning and had to call th AA who found, quite quickly that the seven month old Lucas coil was not sparking. Although the vintage type sticker n the coil says made in England, it seems the coil was actually made in Shanghai. I would have expected it to last a bit longer though my new NGK coil is the fourth in 20 years. Anyone else had a similar problem with new Lucas coils? Are modern Lucas components of poor quality?

pgp001
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Re: It's never the coil?

Postby pgp001 » Fri Jan 26, 2018 8:02 pm

I had a difficult to trace misfire on my Austin 7, it would be fine until it got really hot in traffic queues then started misfiring. Once it cooled down a bit at ran perfectly again.

It turned out to be the coil in the end, I realised it was the coil when it burnt my skin when I leaned on it one day.
When I tried to buy a new one all the suppliers were out of stock of 6V coils, so I found a 6" diameter billet of aluminium and machined a large radially finned heatsink for the coil which completely cured the problem until new coils were available again.
I have retained the heatsink on the car to this day as I think it adds a bit of character under the bonnet of my "Special" and always provokes questions about what it is for.

So yes, coils do fail.

You can just see it on the bulkhead at the left hand side here.
Image

Phil

myoldjalopy
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Re: It's never the coil?

Postby myoldjalopy » Fri Jan 26, 2018 8:09 pm

These modern coils have a reputation for failing. As mentioned by a one-time, prolific poster on this site "Probably made in a tin hut in a far away place." His advice - source a known, good old coil.

oliver90owner
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Re: It's never the coil?

Postby oliver90owner » Fri Jan 26, 2018 11:08 pm

Let’s be sure that the AA man actually tested the coil or was there simply no sparks from the ignition system?

Your any age, any manufacture, coil might not be sparking for reasons other than the coil is duff.

As far as pgp100 is concerned, he fixed the symptoms but not the disease. A much simpler, cheaper - and permanent - modification would simply to have fitted a proprietary ballast resistor into the coil supply line. Job done, finished and the system would have been practically as designed.

Most coils are, in fact 6 volt as far as the working innards are concerned. They are made to work with 12 volt systems by building in the ballast resister into the package, thereby increasing the static resistance from about 1 1/2 Ohms to 3 Ohms. Using a 6 volt coil will double the current in the circuit and most certainly shorten the life of the contact points. Certain, because they are simply not designed to carry 6 amps!

Ford, back in the 1970s, fitted 6 volt coils to their cars to improve starting. The coil was fed through a ballast resistor to prevent it overheating. At start up, the ballast resistor was bypassed, effectively supplying 12 volts while the starter motor was operating. The simple way to do it was to connect the coil to both the ignition switch (for normal running) and from the starter motor side of the solenoid (which only provided the extra current when the starter solenoid was operated). A simple fix for high current starters and small battery combinations.

Now, back to your fault. Is it no spark from the system or really a dead coil?

youngb506
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Re: It's never the coil?

Postby youngb506 » Fri Jan 26, 2018 11:26 pm

Well, the bashed up old coil he had on his van instantly solved the problem, but he also tested the old coil with his multi meter.

oliver90owner
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Re: It's never the coil?

Postby oliver90owner » Sat Jan 27, 2018 9:25 am

Fair enough. It is just that so many ‘won’t start’ threads begin with something that is a wrong assumption.

I have a few old tractors around, which I intend to sell. One or two will likely have new coils fitted, when they go - so i have a couple of good coils in stock.... :D

Sandun
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Re: It's never the coil?

Postby Sandun » Sun Feb 18, 2018 5:08 pm

Lucas green box coils have lot of numbers , you want to put correct number Coil - anyone says when hot stop engine and run back again , it is problem of the condenser with damaged points ,

And always burn condensers , that is the problem of Coil .

Specially your Rotor arm want to be a NOT Revet one .

Why the engine hot - 1. Not good Driving & not run correct gear , 2. Trouble of igniation system , 3. Trouble of cooling system .

Best Of Luck


kennatt
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Re: It's never the coil?

Postby kennatt » Tue Feb 20, 2018 7:16 am

Roys favorite quote, I once replied to him with, I agree with you its never the coil,but sometimes it is :)


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