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Jack Higginbotham
New User
Username: jackh

Post Number: 10
Registered: 6-2015
Posted on Monday, 07 September, 2015 - 10:55 am:   Edit PostDelete PostView Post/Check IP

Hello all,
I just unceremoniously had the Silver Cloud dropped off at my house from a tow.
Here is the story: I drove the car about 75 miles today. About five miles from home the car suddenly and completely shut down. At the moment of failure, I was turning the rear air conditioner off and lowering the electric windows. The car drifted to a stop. The starter turned but no ignition. After a few minutes poking around, I saw a lead wire to the coil was broken. Happily, I thought I had found the simple issue. After repairing the connection, there was still no ignition. I am waiting for the morning....and assuming the coil is involved. If this series of events strikes anyone, I'd love to have my diagnostics sped up!
Best regards,
Jack
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Christian S. Hansen
Frequent User
Username: enquiring_mind

Post Number: 60
Registered: 4-2015
Posted on Monday, 07 September, 2015 - 11:39 am:   Edit PostDelete PostView Post/Check IP

Fuses? The combination of events may have been entirely circumstantial, but on the other hand, one or the other may have shorted/overloaded and blown one of the fuse wires. You do have spare fuse wire in the fuse box?
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Jack Higginbotham
Experienced User
Username: jackh

Post Number: 11
Registered: 6-2015
Posted on Monday, 07 September, 2015 - 09:32 pm:   Edit PostDelete PostView Post/Check IP

Thank you Christian,
I did pull and check fuses before I found the broken coil wire. The only one blown was the cigar lighter, which I don't imagine is involved, but I will repair. After a few cups of coffee, I will be getting to the garage.
I spent some time last night on the web looking for similar situations, but didn't find my exact scenario. I agree with you....it seems I had a lot of electrical load, and suspected a main fuse. The coil wire surprised me..... As you said, it could be circumstantial.
I will check the coil with a test light and check my repair connection for starters. Thanks again.
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Jim Walters
Experienced User
Username: jim_walters

Post Number: 42
Registered: 1-2014
Posted on Tuesday, 08 September, 2015 - 03:10 am:   Edit PostDelete PostView Post/Check IP

Coils rarely if ever just quit. They will give lots of warning with difficulty starting, (worse when warm) and an engine miss that gets worse the more load is put on the engine (accelerating up a hill).
It's more likely ignition switchbox contacts or fuel pump. Do you hear the fuel pump clicking? It is on the same fuse as the coil. Check for power at coil with key on, if there is you should hear the pump click if you push a tickler on a carb float bowl. No pump ticking when you depress the tickler with power to the coil then the fuel pump is your problem.

SRE22493 NAC-05370
www.bristolmotors.com
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 485
Registered: 5-2015
Posted on Tuesday, 08 September, 2015 - 05:25 am:   Edit PostDelete PostView Post/Check IP

Ignition coils are about the most reliable bit of the ignition system. However they can fail. Easy to check connect one side to positive and other to negative and disconnect one side to produce a spark from the tower. This is not a definitive test an oscilloscope is needed for that.
Most coils fail because of high ohms in spark plug leads and the king lead especially. Other causes are coils loose in mounting bracket causing a fret hole and the oil leaks out and dents and stupid mechanics doing stupid things.
Genuine Lucas coil is 10 to 15 quid so quite cheap.

I suspect that you have a simple wiring fault.

The switch box can wear especially if a heavy bunch of keys is swinging from it for 60 years.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1659
Registered: 6-2009
Posted on Tuesday, 08 September, 2015 - 08:32 am:   Edit PostDelete PostView Post/Check IP

And, having been the victim of "sudden stops" due to both a fuel pump failure and ignition failure you're far smarter to check the fuel pump first. If it has died it's a much simpler fix than trying to figure out where, exactly, the dead link in the ignition system is.

Brian
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Jack Higginbotham
Experienced User
Username: jackh

Post Number: 12
Registered: 6-2015
Posted on Tuesday, 08 September, 2015 - 08:59 am:   Edit PostDelete PostView Post/Check IP

Thank you all.
I did check for fuel early on in the process, and I did suspect the ignition switch but came to the issue before going there. The problem is solved, I believe. When the car would start, I would have full voltage at the positive coil terminal. When the car stalled, no reading. And the coil was pretty warm. And no spark obliviously. I swapped the coil ( unbelievable found a match at a local Napa auto supply) and did a 30 minute test drive, no issues. (The longest the car ran at idle with the old coil was a few minutes)
I will be ordering some replacements from Greg Albers tomorrow for piece of mind. Poking around, I see all sorts of shabby bits that could need help....distributor cap, plug wires, etc. Thank you again all. This is a great forum
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 1660
Registered: 6-2009
Posted on Tuesday, 08 September, 2015 - 09:41 am:   Edit PostDelete PostView Post/Check IP

Jack,

It's in no way "unbelievable" that you found a match at a local NAPA. Rolls-Royce was (and is, in automobile industry terms) a very small operation and they didn't make the majority of the "common service items" that our cars use. The Crewe habit (and it's not just limited to them, but it was an art form there) of assigning their own part numbers to every blessed part, whether they actually made it or not, effectively masked the actual manufacturers and model numbers for a lot of parts.

In my now just short of 10 years of SY car ownership I try to convince myself that "part of the charm" is determining what a great many of the parts my cars use actually are, and documenting that for other custodians so they can just run down to their local NAPA, AutoZone, Advance, or similar to pick up service items rather than shipping them from the UK or RR specialty shops when that's completely unnecessary.

Brian
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Jack Higginbotham
Experienced User
Username: jackh

Post Number: 13
Registered: 6-2015
Posted on Tuesday, 08 September, 2015 - 09:45 pm:   Edit PostDelete PostView Post/Check IP

Brian,
Thank you, and on that note, I found an old article online where the author was sharing that exact information....cross referenced, tested and approved "common" parts for SC I and II. Duly noted!
Going back to my original issue, does anyone know if a bad coil would, for any reason, directly cause a break at the terminal if the positive lead? It seems amazingly coincidental that these two things happened simultaneously. Or could runng with a broken lead wire actually damage the coil. Some internet research has yielded no answers, so I defer to the experts.
Best regards,
Jack
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Mark Aldridge
Prolific User
Username: mark_aldridge

Post Number: 250
Registered: 10-2008
Posted on Tuesday, 08 September, 2015 - 11:18 pm:   Edit PostDelete PostView Post/Check IP

Jack, could you post the link to the parts equivalents for SC1 ?
Thanks Mark
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Robert Noel Reddington
Grand Master
Username: bob_uk

Post Number: 492
Registered: 5-2015
Posted on Wednesday, 09 September, 2015 - 08:05 am:   Edit PostDelete PostView Post/Check IP

Or could a break in a wire cause the coil to fail. To both questions no. Because the coil is used to having its circuit broken thats how thw ignition works.

Old cars do stuff like this wires break due to old age hardening and also the terminals on coils can go high resistance where the male spades are riveted.
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Jack Higginbotham
Experienced User
Username: jackh

Post Number: 16
Registered: 6-2015
Posted on Wednesday, 09 September, 2015 - 08:10 pm:   Edit PostDelete PostView Post/Check IP

Mark,
Here is the link, several pages in.
http://www.silvercloudinternet.com/pdf/post55_mag/2004_winter.pdf
Bob,
Thank you.
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Jack Higginbotham
Experienced User
Username: jackh

Post Number: 17
Registered: 6-2015
Posted on Thursday, 10 September, 2015 - 07:39 pm:   Edit PostDelete PostView Post/Check IP

The new parts arrived and all is well. I am still pondering the "coincidence" of the broken positive lead and simultaneous bad coil.
Opinions please on this scenario: the wire failed slowly. It made its way to one single strand of wire for a period of time. Would this damage the coil because of increased resistance? I am having a hard time letting this go.

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