Ignition coil heating up

[jddevel]

Thanks Steve.

[jddevel]

Not good news!!! Checked this morning and the Remax coil reads 3.5 Ohms. The original that I changed read 3.0 Ohms. So the elusive problem still exists. Will get the car into my workshop tomorrow to check over the suggestions so far. BUT please keep them coming.

[Steve Simmons]

I would put in a known good condenser. Don't trust a new one, use one you know works correctly. If you have a good spare distributor, just change the whole thing temporarily to either narrow down the cause to that area, or eliminate it. I would also check the grounds, maybe even ground the distributor just for fun.

[jddevel]

Thanks Steve. Having 24 hours or so off. Feel like a headless chicken at the moment. Sit back and review. Worst part is that I have to wait about 15-20 minutes before it plays up. Means any changes take time to assess result.

[Rob Reilly]

Agreeing with Duncan, it sounds to me like the generator voltage is too high.

What happens if you disconnect the generator wires and run it like that for a few minutes?
Don't let the loose wires touch ground of course.

I found instructions on how to adjust the regulator in Ball's T series workshop manual.

[Ray White]

With the battery being over charged, while I agree adjusting the regulator could reduce it, I would first want to establish why it is at 15 and not 13.5 V. I suspect the high voltage readings are a symptom rather than the cause.

I do, of course, welcome correction... if I am wrong.

[jddevel]

OK so just back from the Distributor Doctor a round trip of just over 3 hours. He is convinced it is/was the condensor. The reason being that whilst one of his ( it was a new one I purchased from the Octagon Club) and although it tested OK when reinstating in the distributor. It fell apart or rather the bracket soldered to the condensor fell off. It showed corrosion between the two items due to, he assumed, either flux or even moisture. Apparently both he and indeed Lucas use to fix the two parts together by drilling 4 holes in the bracket and soldering through them. He reported that these early condensors did fail and so were changed to one larger hole and then again soldered through. I will be refitting the distributor later today and test to see if problem is solved. I certainly hope so!!!

[jddevel]

Thanks Rob for your notes

[Duncan M]

The ONLY adjustment you should try to lower battery voltage from being over 15V is discussed in the center document, figure 11.11 under 3. The screw B should only be turned a very small amount.

If the screwdriver slot can be viewed as the hour hand of a clock, you would only want to try about a half hour of change.
Pic shows change from 10:00 to 9:30.

[Ray White]

So what could have caused the original setting to have changed?

[Rob Reilly]

I would look for corrosion in the rivet connections on the back side.

[Steve Simmons]

It's a mechanical device, so springs weaken, points corrode, etc. Once it's been calibrated it should be good for another 20+ years.

[jddevel]

Had it running at 2000 plus revs for about 15/20 mins. Engine temp. steady at just under 85. Air temp. 18 centigrade. Coil was hot to touch but no apparent problems. Waiting now for higher air temp and will then road test. Sort of optimistic.

[Tim Jackson]

I hope you've finally got it sorted. My experience of similar symptoms may be of interest (article in the MG Octagon Bulletin)

[jddevel]

Thank you Tim. I'll look at the cutout tomorrow before my road test. As I reported earlier in this topic I did feel that the over charging was a contributing factor if not the basic cause to my problem but had sort of been reassured that that was doubtful. Having had to cut short one road trip in Spain/Portugal and another in a couple of weeks to France I'm desparate to get it sorted. Cheers Jan

[jddevel]

Short road trip with hills. (20 K). Ambient temperature 16/17C. Engine ran cool with no problems. Coil hot on return and battery charged showing 13.2 volts on tick over so happy with that. Fingers crossed problem solved. Faulty NEW condenser - the one with four solder points and known by Distributor Doctor as being prone to failure). Will take for a longer trip Saturday as air temperature should be hotter.

[Steve Simmons]

Glad it was easy. I've seen this type of failure before. The coil usually gets blamed but the first thing I always do is change that condenser. I hate to sound like a broken record, but never trust new parts! I carry a complete distributor in the car, and all the parts have lots of miles on them so I know they work.

[jddevel]

Although currently happy, I`m a little pessimistic. Something in my mind tells me there is more to the failure than currently known, I hope I`m wrong naturally. This weekend will see, as with the fine weather we are promised, a good trip out by clocking up some miles we hopefully confirm all OK.

[jddevel]

Another trip to day-58 miles in 20 degree temperature. All OK until caught in a traffic jam after 27 miles. Engine temperature rose above 85 and once engine stopped failed to start again for some time. Coil very hot. Carbs cool. Once engine temperature started to drop to 85 degrees and cooled coil engine restarted and travelled 31 miles with no problems. So still not 100% confident but maybe getting there.

[Steve Simmons]

Did you happen to try pulling the choke to see if it would start? Just to eliminate boiling fuel.