Overheating coil?

[Hugo]

Two things - I am with you re electronic ignition - when it works it is great, but I don't like anything electronic because I don't know how to fix it. If you had points you could just change points & condenser - five minute jobs.
I once had a very strange experience with an Accuspark distributor on a Morris Minor. When I tried to start it, it would kick back so violently it felt like it would break the crank. Ran perfectly. Started on the handle perfectly. As an experiment, I advanced the ignition timing by some ridiculous amount & it would still run ok and start on the handle. But no matter what I did with the timing, it wouldn't start on the starter motor without kicking back.They even sent me another electronic distributor but it was just the same.
The consensus was that because the distributor is right next to the starter motor, there was some current or magnetic field leaking out of the starter motor or cable which was triggering random sparks. All I know is that I went back to the points distributor & it worked perfectly.
I would take issue with your comment about your MGB. You don't need a good contact between the HT lead and the plug cap - in fact you don't really want a good contact. A good trick to get a reluctant engine going is to pull the plug caps & just rest them loosely on the plugs. You get a fatter spark that way, as it has to fight its way across the air gap or poor connection before it hits the plug gap.

[AshM]

I found this trail very interesting. Some very helpful posts.

I recently fitted an electronic 123 ignition system with the new sports coil as described in David's post. Runs perfectly (Edinburgh to Windsor and back without missing a beat).

However I was concerned to read that John suggests I should remove the Ballast Resistor from my car (1970 S2 FHC - 1R.20607). Mine is still in place.

Would value feedback please.

regards
Ash

[Hugo]

Here is a non-electrician's answer; if you run a coil without a ballast resistor when it should have one (i.e. 7 volt or 9 volt coil or whatever they are), you will cook the coil. If you run WITH a resistor when the coil does NOT require one (i.e. a 12 volt coil), my guess is it will not run very well at all. The only thing harmed will be your blood pressure when you curse it for refusing to start.
The fact that yours runs well suggests that you have the correct set-up.

[cactusman]

Just to clarify...I have the original dmbz6 distributor which i fitted with an electronic points replacement module from accuspark along with a red rotor. Fitting took 20 minutes and required no internal modifications to the distributor. I carry the points and condenser in the boot so if it ever fails it would be a 20 min (max) job to restore the points. Thus far though, it has performed fruitlessly after four years of driving.

[JagWaugh]

Just to clarify...I have the original dmbz6 distributor which i fitted with an electronic points replacement module from accuspark along with a red rotor. Fitting took 20 minutes and required no internal modifications to the distributor. I carry the points and condenser in the boot so if it ever fails it would be a 20 min (max) job to restore the points. Thus far though, it has performed fruitlessly after four years of driving.

"fruitlessly after 4 years of driving"? If it hasn't started to work after 4 years it's probably not going to happen - put your original points back in and try it like that.

[chrisfell]

Just to clarify...I have the original dmbz6 distributor which i fitted with an electronic points replacement module from accuspark along with a red rotor. Fitting took 20 minutes and required no internal modifications to the distributor. I carry the points and condenser in the boot so if it ever fails it would be a 20 min (max) job to restore the points. Thus far though, it has performed fruitlessly after four years of driving.

"fruitlessly after 4 years of driving"? If it hasn't started to work after 4 years it's probably not going to happen - put your original points back in and try it like that.

Oh the joys of predictive text software, or pterodactyl two degrees if your fingers are as careless as mine.

[johnetype]

However I was concerned to read that John suggests I should remove the Ballast Resistor from my car (1970 S2 FHC - 1R.20607). Mine is still in place.

Ash, it won't hurt to leave the ballast resistor in place but when you've got electronic ignition and a correctly matched 12 volt coil as you have you don't need the resistor. Leaving it in place means it's wasting energy that should be going to the coil and into a nice spark for good starting and running and you're not getting the best from your electronic ignition system. Also the resistor and it's associated relay and connections are all potential failure points in your ignition system which you want to be as simple and as reliable as possible.

John

[cactusman]

Predictive text....Bain of my life......faultlessly of course

[JagWaugh]

Predictive text....Bain of my life......faultlessly of course

"For a complete list of the ways in which computers have failed to improve the quality of your life, press "1" now."

[Hugo]

To paraphrase Sir Francis Bacon; Computers make great servants but bad masters.

[AshM]

Thanks for response John; appreciated.

I shall take your advice and remove Ballast Resistor. You talk about the associated relay. Not sure I know which one you mean.

Would value more detail please.

thanks
Ash

[mgcjag]

Hi Ash....if you have a ballast resistor then you also have a relay that goes with it....when you turn the key to start 12v goes to the coil via the relay... as it starts and you let the key go relay releases and ballast resistor is put in the cct.....search e type ballast Cct... or look on your wireing diagram.. Steve

[Hugo]

I'm not claiming any superior knowledge here, since I'm fairly new to E Types, but why would Jaguar introducethe added complication of a relay? All they need to do is take the 12 volt feed off the starter circuit. Key start switches normally kill the feed to the resistor when you turn it to the 'start' position, and provide a direct feed to the coil, but even with the push button starter switch it wouldn't hurt if you had 12 volts going to both sides of the resistor, would it? (in other words, both the 'normal' feed to the resistor plus the 12 volt feed straight to the coil from the starter circuit, which would then feed back to the other side of the resistor). Or am I missing something?

[AshM]

Appreciate the posts guys but still confused. I don't think I have a relay wired to the Ballast Resistor.

My S2 has the 'standard 5' unless I am being really dim here.

Best
Ash

[Hugo]

If there IS a relay, it would more likely be found supplying the direct 12 volt feed to the coil - activated by the starter circuit. As I said however, I can't see why one would be necessary. Why take a feed from the starter circuit to operate a relay when you can just run it direct to the coil. I'm not saying there isn't one - because I don't know - I just can't see the point of it.

[mgcjag]

Hi Ash.....you have a ballast resistor.....is it still in use....has tbe previous owner removed the relay ....easy way to check..switch on ignition and listen for a click.....or test the voltage going into the coil..12v with ignition on 6v with engine running..Steve https://www.google.co.uk/search?q=e+typ ... lXVZVoPvgM:

[Series1 Stu]

Hi Steve

You've told Ash that there should be a relay but haven't told him where to find it if, indeed, it is fitted.

Not having a car with ballast resistor and relay I can't advise but it may help Ash if you can tell him where to expect to find it.

Cheers

[mgcjag]

Hi Stuart....if i knew where it was i would have told him......dosnt take much doing to find it......iv already told Ash what it does...as i said he has the resistor does he even still have the relay. Steve

[Hugo]

Well, I don't know - if it's there at all, it could be well hidden. It won't be feeding the resistor, so you can't just trace it back from there. I suppose you could trace the other, direct 12 volt, feed to the coil back & see where it takes you. Trouble is you're looking for something which may or may not exist, and if it does exist you've no idea where to look.
Somebody suggested switching on the ignition & listening for a click. I think it's far more likely, if you're going to put a relay anywhere, that you'd put it in the starter circuit - i.e. to activate the direct 12 volt feed which bypasses the resistor. In which case you'd be listening for a 'click' when you hit the starter. Could be tricky!

[christopher storey]

There is no relay . When the starter is operated, the switch is arranged so that, as Hugo has said, 12v goes direct to the coil from that circuit. When the switch is released, the switch energises the circuit in which the coil is fed through the ballast resistor