The 'E' Type Forum

OK - I am sure this is a stupid question but I am struggling. I have a 66 series 1 2+2, previously was running OK for a short period (couldn't run too long as no coolant) but since I replaced the cooling pipes it is turning over but won't start. I checked for spark and was getting none at the plugs, so started to investigate the points/ignition wiring to see if I had dislodged anything. Removing the distributor cap, I can see that the wire from the input to moving contact seems to have burnt out. I replaced this and now get a spark at the plug, but looks weak.

I thought I'd investigate why the wire might have burnt out before going any further, and checked the HT lead from the coil to the dizzy cap. On removing it at the coil (acorn screw-in type) it appears that the brass disc is missing which might have increased resistance causing it to overheat?

Long story short, I've decided to replace the whole lot as I had planned to upgrade to electronic ignition once the car was up and running anyway. Probably looking at a bluetooth 123, new coil and new leads. Looking at the old coil, there are 2 wires connected to the "SW" side - one switched 12v, and a green wire that runs through a small cylindrical object to ground. When I check continuity, there is continuity from this side of the coil to ground, despite this being the 12v input side. I always assumed the small cylindrical object was a ballast resistor, but it doesn't look like any pics of ballast resistors that I see online:



Am I missing something or being stupid here? With electronic ignition, I presume I don't need a ballast resistor anyway?

This looks like a condenser to me though I don't know what it doing down there.

It is a radio interference capacitor which you don't need. It is also a high failure rate component especially when exposed to heat. It can go open circuit or short circuit, the latter causing all sorts of running problems. Bin it!

For radio suppression you should use resistor spark plugs such as BPR5, the R standing for resistor.

You could also fit a new coil now. But buy a good quality one as there are quite a few poor quality copies out there.

Geoff

So if the radio interference capacitor is faulty that would explain why the +ve terminal shorts to ground, and might explain why the coil wire in the dizzy melted?

I plan to bin the whole lot and start from scratch with electronic ignition. New coil, no ballast, 123-ignition and new leads.

Shame no-one ships between xmas and new year, guess I'll have to wait a bit longer!

Have it running again. Removed the capacitor, new wire in dizzy, botched the HT lead from the coil for now with a washer. Started fine and running OK - bit lumpy at idle. Managed to drive it out of the garage - first time the car has moved under it's own steam in about 10 years!

Before you throw complexity, modernity, and money, at a car where there may - perhaps, in the context you describe - be lots of other sub-optimal issues .......... bear in mind what follows.

Whilst my car runs brilliantly on Megajolt, when I reverted (road-side, as a break-down resilience test, takes about 5 minutes) to coil/points/condensor and mechanical advance, it continued to work brilliantly.

I'm even tempted to think the mid-range is even better on points than with the Megajolt (map taken from the KB) which is why in the Spring it will be in the UK to be mapped on a Dyno.

I did pay the Distributor Doctor to completely rebuild the original one, with a tested and plotted advance curve dead on spec, and it did cost me more than many electronic ignitions, BUT in my humble opinion (Ed - ??) it suggests (what we all secretly know, or ought to) that Jaguar were not stupid, and that much of the money and "improvement" we throw at our cars is quite simply a nonsense.

There seems to be an underlying opinion that Jaguar were incompetent and penny-pinching but this simply can't be true, otherwise the marque would have sunk into obscurity a long time ago.

They produced cars that out-performed many of their rivals costing double the price or more and had better build quality.

They look spectacular too.

Regards

I think the big issue is component quality. I don't trust modern repro caps, rotor arms, condensors, points etc as I've seen too many failures. Thats why we fit silicone leads with a 123 tune dizzie.

Interesting testimony, Rory, especially for me who is thinking about that issue for the next (hopefully) fire up of my engine when reassembled. However it assumes that you find good spare points and capacities. So if one of the readers here would be nice enough to explicitly give one or two links to a fair provider, it would be of great help.
and

Distributor doctor.....only place to purchase ignition parts
https://distributordoctor.com/ but as Angus mentions 123 is a good way to go....Steve

Thanks all. I switched to a 123 dizzy in my beetle around 4 years ago and it run beautifully, so I'm looking for the same reliability and performance in the e-type. I know properly set-up points/condensor will likely offer at least as good performance, but possibly less reliably with more maintenance in the long run. Given that everything needs replacing anyway, I'm going electronic.

I also quite like the idea of the immobiliser feature in the 123-tune BT dizzy...

Thank you Steve. I should have guessed!
Happy new year!
Philippe