correct ignition coil?

[Dieter H. Marschall]

Hello everybody,

After I have installed the SU HIF6 carbs I am quite happy with them. There is a slight problem, however, when I try to restart the engine after some longer driving.

This might be due to the fact that now I have installed two oval K&N filters directly on the carbs, i.e. they draw hot air from above the engine.

I realized, however, that the ignition coil is very hot after some time of driving. So I keep wondering whether this might be the reason for my "hot start issue".

The ignition is a Lumention. The ignition coil is a "Lumenition Magna Spark 4" with 40 000 V and 1.5 Ohm resistance. As my Stag is a Mk1 I have the ballast resistor built in, too.

So my questions are: Do I have the wrong ignition coil built in? Should it be a 6V or a 12V coil with my constellation?

Thank you in advance for any help.

Kind regards,
Dieter.

[richardthestag]

if you have ballast resistor built in and feed the coil with a white/pink wire I would have thought you use a 6v coil.

Make sure that the bottom of the coil is clear of the engine block though. If the coil is sitting on the engine block this will not help the coil to keep cool.

p.s. edited to add a 12v coil running on 6v ballast resistor feed wouldn't get hot ?!? but a 6v running at 12v will definately get hot and very quickly. Mine also lunched a perfectly good dizzy cap

[V Mad]

Dieter, could it be the dreaded E5 fuel? Are you getting vapour lock?

If you think it might be electrical, are you sure your ballast is connected correctly? Just to be sure, connect the coil neg to ground, switch on ignition and measure the voltage at the coil POS. If you get about 12 volts the ballast is not in circuit; if you get around half that value the ballast is dong its job.

I make no secret of the fact that I distrust Lumenition ignition. If its not a fuel problem my bet is that the Lumenition is breaking down and is the cause of your problem.

[Dieter H. Marschall]

ignition coil

Hello Richard and Chris,

I already have relocated the ignition coil away from the engine block to the rhs. inner wing to keep it cool.

It might be a vapour lock, as this problem cropped only after I replaced the Strombergs by SU HIF6 carbs. Thus I had to build in K&N filters, which draw their air directly from above the engine. See pic.

Kind regards,
Dieter.

[Dieter H. Marschall]

P.S.: I measured 8V between pos. and neg. at the coil - with ignition switched on.
Best wishes,
Dieter.

[V Mad]

Thats probably ok then.

[Klaus Schlueter]

Dieter, could it be the dreaded E5 fuel? Are you getting vapour lock?

Hi Chris, why dreaded E5 and vapour locks?

Klaus

[V Mad]

Vapour lock seems to be getting more common with modern volatile fuel; whether Ethanol contributes to this I am not really sure. What do you think Klaus?

[Klaus Schlueter]

Goog evening Chris
Sorry for the delay. I agree with you and I will publish my thoughts in a seperate thread.
Watch the forum.

Regards Klaus