Alternator or Starter Motor?

[Bret]

OK – I see what you are talking about. This is the Starter Solenoid Relay. This relay is part of a “standard” low current circuit relay controlling the higher current primary “Starter Solenoid” that engages your starter to the flywheel and connects battery power to the starter.

IMO The starting & charging circuit in this schematic isn’t all that much different form mine. (74 vs. 78) But if you follow the circuit closely – I think you’ll find it would be a little hard for this to cause the problems you’ve had with charging thus far. Even if the relay was bad. Mind you - this isn’t to say that you won’t find more Lucas ghosts haunting other parts of your car’s electrical system down the road. The chances of this happening seem to go up exponentially the further you are from home or a good mechanic. ;-)

Anyway I’m happy to see that your making the best of your time while you wait for the new Alternator. If you haven’t already – go ahead and clean up the terminals as best you can. And look to see if any of your connections need to be re-terminated and/or replaced.

Bret

 

[StevenA]

I had a similar problem a number of years ago with my 77B and again with my 79B. I followed almost every guide that I found in "trouble shooting" and the guys here have hit on most of the problems. Print out the advice here and "do them all" and you will be driving in no time. I went to the trouble, at the time, because I thought I had a dead short ...to clean every terminal, every connector (including light bulb connectors/fittings) and every ground wire that I could find. Overkill seems to be my forte' ...but somewhere in the time (fun time) spent; the problem dis appeared. Good luck...it is all good advice. Lucas has lots of gremlins... that is the fun and frustration both.

 

[StevenA]

PS on parts ...Moss is a good source...so is Victoria British. I have a local source that has the parts on hand ( only once has he not had a part and that was a set of MG wheel caps...only had one on hand )and that is Sportscar Warehouse ( sportscarwarehouse.com) in Arlington Texas and he has always been a few dollars cheaper than Moss or Victoria British, eventhough he is a dealer for both. Plus the guys there are mostly Brits...so they understand British autos from childhood. Byron, the owner, is American but is fluent all the way back toMG beginnings. They will give advice by phone; they like to help.

 

[Obtong]

My alternator arrived today. I took the old one off the MG, but I am having an awful time getting the nut off it so I can remove the old pulley and fan to use on the new alternator.

I tried a wrench on the pulley, as well as heat and a penetrant, but I've had no luck. I slightly bent one of the fan blades (fixed) trying to get the thing off, so now I'm worried that I'll do more damage to the fan and/or pulley.

Any suggestions or should I just order new ones?

Obtong

 

[Gary Lloyd]

You need an impact wrench!! It will come off as slick as can be with one of them babies!!! If you don't have one, go to a local garage, it will cost peanuts!! GOOD LUCK!!

 

[Obtong]

Great! I'll go in to a garage tomorrow morning and have them remove the nut. BTW, should I have them put the pulley and fan on the new alternator with the impact wrench?

Thanks,
Obtong

 

[Gary Lloyd]

No, just hand tighten it! It is designed to tighten as it spins!!

 

[Obtong]

Well folks, I took the old alternator into a local garage an they removed the bolt in no time. (It cost me nothing.)

I installed the alternator in about 30 minutes. The ignition light turned on when I turned the key, but when the engine started the MG's voltmeter showed no reading. The voltmeter connected to the battery did show a charging state of about 14.5 volts however.

I turned off the engine, restarted, and this time the MG's voltmeter registered a charging state as well. Hmm...loose wire, new alternator characteristics?

Anyway folks, thanks for all you help. It has been great!

Obtong.

 

[Gary Lloyd]

HMMM! Did you check all your connections??