MG Car Repair: 1979 MG Midget (USA) ignition coil leaking, soda crystals, litmus paper

Question
Greetings, Mr. Jones.

I've read several of your thorough, well-worded replies on AllExperts, and it seems you may be just the gent to whom I should address my question.

I just acquired a '79 Midget that had been parked in a warehouse for two years.  I purchased a new, slightly larger battery (which according to the auto parts store was the correct one# and tried to start the car with no luck.  

After the car sat unattended for a couple of hours, I returned and noticed a faint sizzling noise, and a puddle of moisture under the car.  I traced the source of the puddle up to the ignition coil and quickly disconnected the battery.  

Now I'm here writing this message and hoping that you can shed some light on the situation.  My assumption is that the battery was too large, but I'm wondering if the ignition coil #or anything else) has fried.

Any help is appreciated!

Thank you!

Bill Casey

Answer
Hi Bill.  Thank you for your comments.  I am concerned about the sizzling noise that you heard.  Is it possible that your battery (either the new one or the previous one) has leaked acid creating the puddle under the car?  Also, is it possible that a dribble of acid has run over the coil, eating a hole in it?  As a matter of urgency, I would remove the new battery and look for any sign of an acid leak.  Hydrochloric Acid is nasty stuff that can eat right through your car, so if there are any traces then you must wash it all off with a solution of water into which you have dissolved some soda crystals.

The other possiblity  is that you have an oil-filled coil and it is leaking oil.  They were not fitted to 79 Midgets when new, but may have been fitted as a performance coil by the previous owner.  If you can lay your hands on some Litmus paper, check the puddle to see if it turns red (acidic).  Most school labs have the stuff.  

To check the coil, get a digital multe-meter, disconnect the wires to the coil, and test the terminals on the OHMS setting.  There must be continuity between both small terminals and the HT connection on top of the coil.  You should get a resistance measurement between 3 and 3.5 ohms.  

When re-connecting make sure that the White wires with a Black stripe go to the negative terminal, and the plain white power wire goes to the positive terminal.