Left the ignition on, like an idiot

[Dr Mike Oxgreen]

Can somebody reassure me that I haven't knackered my coil by inadvertently leaving the ignition on for a few hours?

With old style ignition systems with points, I believe the primary circuit current flowed through the coil the whole time when the ignition is switch on, except for momentary interruptions when the current is broken by the points. Leaving the ignition on with this style of ignition is bad, because the coil can get hot and potentially burn out, or at least weaken.

I think that the breakerless electronic style of ignition on the Chimaera has no primary current flowing normally, except for pulses generated by the ignition amplifier. Is that right? This would mean that the coil doesn't get hot if you leave the ignition on.

I felt my coil and it's stone cold, so I'm hoping everything is fine. I haven't tried starting it, because the reason for leaving the ignition on was that I had to push it back onto my driveway due to a rather flat battery, so I'm leaving it to charge.

[Paulprior]

I believe you are right in your thoughts that it should be ok and only receives pulses from the amp, you should be fine when the battery is charged

[Steve_D]

If the coil is cold you are OK.
However, this is likely that the dizzy stopped in the right place. I think it could have stopped with current passing through the coil in just the same way as it could with points.
I stand to be corrected but for now if the coil is cold it was not passing current, they can get bloody hot when they are.

Steve

[Sardonicus]

The trigger needs to be sweeping the pick up to create the pulse to switch the module and thus coil so sitting idle it will produce nothing in other words no damage done

[Dr Mike Oxgreen]

Cool, thanks chaps. As I understand it the rotor arm generates its tiny voltage by moving a conductor through a magnetic field - no movement, no induced voltage.

Accumate is still on amber, but I'm expecting it to take at least 24 hours to recharge, and possibly a lot longer. It has just come back from servicing, so presumably they've been starting it a lot without driving it far enough to recharge. Or maybe my battery is too old - it's probably about 4 years old.

[ianwayne]

I was looking at Chimaera coils the other day because I think I may still be on the original.

Nearly bought the wrong type because I hadn't been aware that the ignition system has a ballast resistor in it. This also helps keep the voltage down and hence the heat generated by the coil apparently until a spark is required.

[Sardonicus]

ianwayne said:

I was looking at Chimaera coils the other day because I think I may still be on the original.

Nearly bought the wrong type because I hadn't been aware that the ignition system has a ballast resistor in it. This also helps keep the voltage down and hence the heat generated by the coil apparently until a spark is required.

The ign system on these cars dont use a ballast arrangement its a 12v coil

[blitzracing]

^^^ This. Its a low resistance high energy coil, as it has to deal with delivering a spark every few milliseconds when the V8 is at full RPM. The ignition amp controls how long it has to deliver the spark, but as the RPM rises compremises have to be made in dwell period (basically there is not enough of it) so the available HT starts to drop off quite noticeably at about 5000 rpm. Basically the coil designed by Lucas to work as is, and really does not need to be messed with.

[ianwayne]

Sardonicus said:

he ign system on these cars dont use a ballast arrangement its a 12v coil

That's not what I read here:

http://www.pistonheads.com/gassing/topic.asp?h=0&a... (blitzracing)

Have I misunderstood? Is the ballast internal to the coil? I wouldn't want to buy the wrong type.

Edited by ianwayne on Sunday 12th February 18:33

[Dr Mike Oxgreen]

Hmmm... This morning the Accumate was still showing an amber light after about 48 hours. On a whim I decided to switch it off and back on again, and it went straight to green and stayed there. Curious.

I'll take the car for a drive later. Hopefully all will be well.

[phazed]

Trickle chargers quite often won't charge from a completely flat battery, mine won't!

[blitzracing]

ianwayne said:

That's not what I read here:

http://www.pistonheads.com/gassing/topic.asp?h=0&a... (blitzracing)

Have I misunderstood? Is the ballast internal to the coil? I wouldn't want to buy the wrong type.

Edited by ianwayne on Sunday 12th February 18:33

There is no ballast resistor as such- but it appeared the feed wire to the coil may have some internal resistance as I got less than 12 volts on the coil positive connection when the coils negative connector was grounded- this made me think the coil was ballasted with a "nichrome" feed wire, but I think its just crap Lucas wiring now dropping a volt or so. If it was ballasted there would be a secondary direct feed wire from the starter to bypass the ballast and this is missing, so I think its safe to say its a 12 volt coil.

[ianwayne]

Thanks for the update. I found reference to a ballast resistor on other Rover V8 sites as well as here such as the Cobra site. A ballast resistor can be used with a 12V system as read here:

http://www.accuspark.co.uk/faqs.html#q1

The fact that there's 2 wires on the +ve side of the coil is misleading though. Sites list the Lucas DLB198 as the part number of the coil to buy, and this is non-ballast according to sellers.