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Q & A: MGC Charging System

Went to fire up the 1968 MGC last week..reconnected the battery ground...tried to fire it up....it was dead.

I disconnected the alternator and put the charger on it.

Yes...Negative to negative and positive to positive.

Battery appeared to re-charge on trickle...

Went to reconnect alternator and ...SPARK!

"This ain't right, I say!"

Pulled the one wire off of the alternator that I had connected (brown).

Then...

I disconnected battery at ground (negative terminal).

Reconnected alternator.

Went to reconnect ground....SPARK at battery terminal.

"This ain't right, I say!"

Any clue as to what's going on here?

OK...The saga continues....

I swapped out the battery just in case it was a short in the battery itself.

I connected the alternator back up (black wire on top, brown beneath it) and reconnected the battery.

It SPARKED at the negative terminal.

For grins, (I would say tickles and grins, but I didn't want to get shocked), I disconnected the alternator and reconnected the ground to the battery. NO SPARK.

I verified that the ignition is indeed switched OFF.

I have a feeling that the alternator, or maybe the alternator control box, is at fault.

In this model of MG, what does the Alternator Control Box do as a function? Could the fault lie here? (My '69 MGC does NOT have this feature.)

Also noticed the one time I did get the C started (a few weeks ago), that the tach would jump to 7000 rmp or so until the car started, then show normal rpm.

The 1968 MGC (and MGB) have an external voltage regulator. By 1969 it was incorporated into the alternator itself.

There is, sometimes, a tiny spark when connecting the alternator, especially on the later style (about 1977... read more