How long should a coil last?

[shed driver]

I've had some poor running and starting issues on my 1973 P5B Coupe. I replaced the coil 2 years ago when I fitted electronic ignition and it ran really well for a while. Since then the poor starting has returned and it seems there's low voltage on cranking which was going to be assessed by an electrician.

I had a spare coil in the garage, fitted it and the car fired up straight away. The electrician will eventually get round to fitting me in, but it may not be for a few weeks at least. Is there any harm running it with a (possible) fault to the feed? Also, how long should a coil last?

SD.

[GreenV8S]

If the coil is the right spec for that installation then it could potentially last indefinitely. A cheap or faulty coil could fail within seconds, hours or months.

If the ignition system is seeing too low a voltage then that will aggravate any other problems you may have.

[davejf]

Most coils these days seem to be cheap rubbish. I’ve got a number of friends who have been stranded by failed new coils. One of them worked in the industry previously and has said they are rubbish, knows they will fail and keeps a spare in the car with him as he has a bit of a supply from when working in that industry. He’s been through about 5 of them in the last 8 years and the car doesn’t do a big mileage.
I on the other hand have coils that are 40+ years old on mine and so far haven’t had a single issue. I have a number of spares that are all 40+ years old and they will be my replacements. I don’t intend to fit a shiny new coil for no reason when it will most likely fail far too soon.

[richhead]

shed driver said:

I've had some poor running and starting issues on my 1973 P5B Coupe. I replaced the coil 2 years ago when I fitted electronic ignition and it ran really well for a while. Since then the poor starting has returned and it seems there's low voltage on cranking which was going to be assessed by an electrician.

I had a spare coil in the garage, fitted it and the car fired up straight away. The electrician will eventually get round to fitting me in, but it may not be for a few weeks at least. Is there any harm running it with a (possible) fault to the feed? Also, how long should a coil last?

SD.

you say you fitted electronic ignition, did you fit the right coil, there are ballasted coils and non, 12v or 9v. it may depend on the electronic system you fitted.
a 9v coil fed 12v all the time wont last.

if im teaching you to suck eggs then i apologize.

[shed driver]

Not at all, I got all the stuff as a single lot from a specialist.

Anecdotally there are quite a few classic owners who are mentioning branded coils, mainly Lucas are now made in China and seem to be failing prematurely.

SD.

[richhead]

shed driver said:

Not at all, I got all the stuff as a single lot from a specialist.

Anecdotally there are quite a few classic owners who are mentioning branded coils, mainly Lucas are now made in China and seem to be failing prematurely.

SD.

blimey i thought lucas stuff was bad before.
would still be worth checking the feed voltage at the coil, on start and running, and making sure you have the right type, it used to be a common mistake when electronic conversions first became popular, yes i am that old.