Replacement ignition coil

[GrahamFountain]

Where's the best place to get a coil where the stuff's good and the prices modest?

I have what I think is an electrical fault. It's intermittent on a very short term, like less than one second to, mostly, a very few seconds; and don't feel like fuel starvation or flooding or such and I don't smell fuel. There was a small amount of popping, possibly after the longer drop-outs.

It doesn't affect the tacho reading so it would have to be HT, and feels like much more than just one pot going off. So I think it's either coil, main lead, connector betwixt, dizzy cap, or maybe arm. Some are more likely than others.

It started when the engine had just nicely warmed up , though I had it nice and warm earlier in the week with no problem - perhaps the briefest oddity just as I was getting home. And it seemed to be getting worse and I though it was going to die. So I stopped to see if there was aught obvious or if it was changed by wiggling anything. But there weren't. So I took the cap off and looked at it, the points and the arm, with no effect. I did re-gap the points by eye, bit except for a slight change in idle when the fault wasn't faulting, that made no obvious difference - I hate intermittents.

So the next job after dinner (can nearly type and eat pudding) is to go through swapping bits and see when and if it goes away. I have almost everything likely except the coil. So we all know which it will be if the fault is in that set.

Graham

[GrahamFountain]

No problems with it coldish - its had about 2 hrs to cool while I made and ate dinner. So I'm letting warm up on the drive and see.
That it's gone away with cooling pushes me to think it might be the coil even more.

Graham

[GrahamFountain]

Back to it barely seconds after last note and it started. Put the strobe clip on the main lead, and sure enough, it stops flashing when the engine loses go and the tacho only dips to follow revs.

So not only do I want a cheap coil, I want it yesterday.

Graham

[yorkshire_spam]

https://simonbbc.com/ignition-coils/

I got coil and points replacement from them 6/7 years ago for the Spitfire, not astronomical prices and it's run well ever since...

[GrahamFountain]

I ordered one of BBClasisccars on eBay, which I think is them. Supposed to be here Friday - Sat. I hope!

Graham

[Awaiting Repair]

So not only do I want a cheap coil, I want it yesterday.

Graham

I guess that’s where your problem could be? Perhaps try a more expensive quality coil?

Not sure about the best one for Dolomites, but on my ‘73 Stag, a Bosch Red coil made a noticeable difference when I replaced the Chinese/Indian/Whatever Intermotor crap variety.

Do some research and by the BEST one?


Cheers
Keith

[Bish]

X2 for the Bosch red coil. I’m convinced my car runs better now I’ve fitted it. And it’s cheap! £27 from amazon delivered to your door

[GrahamFountain]

I got a Sparkrite blue one.

But it turns out it wasn't the coil. In my defence, I didn't expect 2 condensers to show the same fault, though they are from the same supplier (I shall see if I can find the order on eBay and send them a suitable snotogram).

I also thought any LT side fault would either cause the tacho or the voltage measured on the points side of the coil to change distinctly when the spark was dropping out. But, clearly, I was wrong. Maybe if I had a scope I'd have seen it.

And hey! Now I do have a spare coil.

I've also discovered that the white and yellow wire isn't doing anything on starting. So there's a fault to fix when the engine's a bit cooler.

I also found another really rather good condition early 44D4 in the garage looking for the spare sets of points that turned out to be for the 25D4 in the Herald. I think I need that so I'll have one for the TR7 Sprint if it ever moves, and still have a spare for the Dolomite.

It also had a good cap in it, if the points were nearly worn out, so I could make up a good set with one of the points that came with the other crapacitors. And it had a good vacuum unit that gives 10-12 degrees advance with the dizzy mounting bolts near the middle. Not as near as the other good one I have, but better than the bent one and better than the modified 45D one (which I must mention elsewhere). So now I can dare to try to unbend the bent vacuum unit enough to be more usable.

Also, some PO had found out how to defeat the vacuum advance easily. Just leave the spring washer out from the points base plate screw - the one you slacken to set the points gap. That's enough for the screw to bind on the distributor's main base plate so the points are fixed relative to it.

That made me wonder if it would be possible to modify a vacuum unit (a 45D one - they seem more plentiful) so it looks normal, but instead of being operated by the vacuum, turning the diaphragm case acts as a vernier adjuster for the timing, like the 25Ds have.

I know losing the vacuum advance affects emissions a bit, but it won't affect performance. And not replacing the car with a new one has saved pollution than a vacuum unit could possibly save now. Also, having the timing right more of the time might recover at least as much, and would affect performance.

It would need a threaded bar with a hole in the end to go over the pin under the points plate, and a nut inside the diaphragm case (or where it would be, if looking original isn't an issue) that can turn but is fixed longitudinally on the axis of the bar. Not sure if the bar needs a slot and pin to stop it turning, or if the pin under the points plate does a good enough job of that.

Graham

[yorkshire_spam]

But it turns out it wasn't the coil. In my defence, I didn't expect 2 condensers to show the same fault, though they are from the same supplier (I shall see if I can find the order on eBay and send them a suitable snotogram).

The terrible quality of replacement points/condenser sets is the reason I switched the Spitfire over to an electronic points replacement after being stranded at the side of the road when a condenser that was about 3 weeks old failed.
Ever since I've carried a spare points/condenser set just in case, never needed them though.

[GrahamFountain]

Ever since I've carried a spare points/condenser set just in case, never needed them though.

That's why I carry an umbrella - so it won't rain.

Graham