Lucas 23D Points Baseplate

[111Robin]

Thanks. Mine is a 41189 unfortunately. I'd need to check to see the difference in the advance curve.

[2cams70]

What voltage do you measure at the coil between the supply terminal to the coil and ground with the ignition switch turned to the "run" position?

[111Robin]

What voltage do you measure at the coil between the supply terminal to the coil and ground with the ignition switch turned to the "run" position?

11.9V, battery is 12.9V

[2cams70]

11.9V, battery is 12.9V

Please check again only this time do it with the negative side of the coil grounded (assuming the car is -ve ground) to simulate the coil drawing current whilst the points are closed.

Disconnect the electronic ignition whilst doing this test.

[111Robin]

0.2v
I'm now running on points, the coil is still very hot to the touch. Battery voltage running is 14v.

[111Robin]

Engine running, voltage at coil terminals :

+ 13.5V
- 5.5V


With lights on main beam and heater blower on high :

+ 11.8V
- 4.8V

Coil gets very hot, at least with no load on the alternator. Could this explain why I didn't break down when I took it out at night with the headlamps on ?. Is 13.5V going into the coil causing it to eventually give up, whereas 11.8V is ok, as you would expect.

[Andy8421]

Engine running, voltage at coil terminals :

+ 13.5V
- 5.5V


With lights on main beam and heater blower on high :

+ 11.8V
- 4.8V

Coil gets very hot, at least with no load on the alternator. Could this explain why I didn't break down when I took it out at night with the headlamps on ?. Is 13.5V going into the coil causing it to eventually give up, whereas 11.8V is ok, as you would expect.

Robin,

You mentioned in an earlier post that you were able to remove the 'king lead' while the car was exhibiting the symptoms and there was a spark. If that was so, and by 'king lead' you mean the lead from the coil to the distributor, and the spark was decent, then it looks as if the coil and ignition module are working just fine and your problem is elsewhere.

Could you confirm that I understood your earlier post correctly?

Thanks,

Andy.

[111Robin]

Engine running, voltage at coil terminals :

+ 13.5V
- 5.5V


With lights on main beam and heater blower on high :

+ 11.8V
- 4.8V

Coil gets very hot, at least with no load on the alternator. Could this explain why I didn't break down when I took it out at night with the headlamps on ?. Is 13.5V going into the coil causing it to eventually give up, whereas 11.8V is ok, as you would expect.

Robin,

You mentioned in an earlier post that you were able to remove the 'king lead' while the car was exhibiting the symptoms and there was a spark. If that was so, and by 'king lead' you mean the lead from the coil to the distributor, and the spark was decent, then it looks as if the coil and ignition module are working just fine and your problem is elsewhere.

Could you confirm that I understood your earlier post correctly?

Thanks,

Andy.

That is correct Andy, however this was after a lengthy wait at the side of the road, not at the point when it broke down, so the coil could have recovered when it cooled down. As soon as I put the king lead back into the coil the engine fired up and I was able to drive home.

[mbell]

Do you have a IR thermometer you could use to check coil temp?

[111Robin]

Do you have a IR thermometer you could use to check coil temp?

Unfortunately not. It is excessive though. All of my other cars run dynamos so I can't really get a good comparison.

[snowyelan]

Following this with some interest. I have a misfire that I have yet to figure out. I read that you have a new coil, 3 ohm type. Have you checked it with a meter? Based on experience with what I have been sold, and what's actually in the package, its possible there was a mixup and you have a lower ohm coil.

[mbell]

I switched my car over to ballast + 1.5 ohm coil. I miss wired it and was running the it in bypass mode at first. It took ~hour driving to start having a noticeable issue, slight miss fire under limited set of conditions. I made it another 15 miles home to discover the issue and measured the coil at around 65 degrees C. This was on frame thrower coil, which should be decent quality.

I'd be tempted to test/swap your coil to rule it out.

[111Robin]

Following this with some interest. I have a misfire that I have yet to figure out. I read that you have a new coil, 3 ohm type. Have you checked it with a meter? Based on experience with what I have been sold, and what's actually in the package, its possible there was a mixup and you have a lower ohm coil.

It measures 3.6 ohms primary resistance. It's a reputable brand, bought a month ago.

[111Robin]

11.9V, battery is 12.9V

Please check again only this time do it with the negative side of the coil grounded (assuming the car is -ve ground) to simulate the coil drawing current whilst the points are closed.

Disconnect the electronic ignition whilst doing this test.

Points open, 12.75V at both terminals
Points closed, 11.8V +, 0.23V -
Primary resistance 3.6 ohms
No ballast resistor

[2cams70]

Points open, 12.75V at both terminals
Points closed, 11.8V +, 0.23V -
Primary resistance 3.6 ohms
No ballast resistor

Next step measure the current draw from the coil under each condition - points closed and points open. Put an ammeter in series with the coil supply wire.

By the way have you tried driving the car yet with the system reverted back to points?