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MG MGB Technical - Dead battery...or?

Hopefully I have a simple problem on my hands. Three days ago my 1977 MGB would not start...dead battery. So, being on a hill, I rolled it and popped the clutch...bingo!..on the road again.
Today, a nice sunny evening drive with my wife, and the car starts running rough. Then while driving about 40 mph it stops altogether. So, I coasted to a stop, and after checking under the hood to no avail, my wife suggested calling AAA. So we had it towed home.
I put the battery charger on it again and its completely dead. How do I go about checking to see if its the battery that won't hold a charge? Or, is it the generator that's not charging the battery?
And finally, if the battery is dead, would that cause the car to stop. I have an Allison electronic ignition installed by the PO.
My best guess at the moment is that the battery, dated 1997 I believe, is done for. And this is probably making it impossible for the electronic ignition to work.
What do you think?
Cheers,
Randy Olson
1977 MGB
randy olson

Could be battery -- or charging system -- or dirty battery connections.

Also, if you can, check electrolyte in battery and top off with distilled water.

clean the terminals.

If you can get it to start, turn on headlights -- observe if they dim and brighten with engine speed.

check for connections between alternator voltage black box -- (big brown - brown / yellow)clean them if necessary and tighten.

these are "first look" stuff. try these, and any other suggestions and post results.
glg

I had cleaned the terminals on the battery a few days ago and thought that was the problem. Tonight I checked the electrolyte and, sure enough, it was very low. So I just filled the cells with distilled water (after a quick trip to the store) and am continuing to charge. As soon as it's charged up I'll try starting.
How about the electronic ignition? Does it require power from the battery to operate smoothly?
Regards,
Randy Olson
1977 MGB
randy olson

In order to survive yet another Ithaca winter I would suggest a new battery in the near future but yes, in a nutshell, all your electrical appliances run off the battery. The charging system recharges the battery. No juice, no spark, no go. (Unless PO installed an small aircraft magneto!!--just kidding) This is why GLG above suggests your charging system, connections etc.

Before the car died the other night, did you notice your headlights dimming or other electrics underperforming? If so, charging system, perhaps battery.

Paul
Hotel 82

Paul Hanley

The problem may be solved. After adding the distilled water I charged the battery a little. The car started right up and ran beautifully on a quick, short test run. I'm charging it fully now and suspect the problem was simply that the battery fluid became way too low.
The headlights did not dim when the engine was reved.
By the way, the Ithaca winters don't allow the use of the B, so it's going into storage in a month or so.
Thanks to all,
Randy
randy olson

1997 battery is over the hill. When batteries get old and weak, they use a lot of water. First cold weather and you'll find that there's not much charge on that battery. Buy a new battery from a reputable dealer...they usually check your charging system as part of the service.
R. L Carleen

Good news for late in the season, but a new battery should be on your list.

Just a point of clarification: the headlights would brighten on reving the engine, by increasing alternator output -- IF the battery was very weak.

Just a side note from personal history - before I knew the fine points of polorizing the generator charging system -- the electronic ignition (Crane) would operate only if the headlights were turned off. That, of course was because I was not getting charge to the battery.

Good to hear good news!
glg

Randy. Your car has an alternator, not a generator. Once the car is started, you should have been able to run on the current provided by the alternator. The fact it did not may point to a charging system problem. The fact that your battery was low on water can also be a sign of an overcharging (one of the failure modes of alternators) system. Hence, I would replace the battery with a new one and have the alternator checked for output in both volts and amps. You can do a quick check by measuring the battery voltage (should be 12.0-12.5 volts), starting the car and checking the voltage at the clamps. (Should be 13.5-14.5 volts.) If you have more than 14.5 volts, the battery is being overcharged and the electrolite will boil off. Charging output, in amps, must be checked by an alternator test machine. Takes a few minutes. I had an alternator that put out sufficient voltage, but only 17 amps. Not sufficient to run the car and re-charge the battery properly. Les
Les Bengtson

It was plainfully known Randy has an alternator.

Any mention of generator problems were in respect to the amount of drain from a battery that is not getting charged.

That reference, as presented with "side note of personal history" was noting but an example of a similar problem. nothing more nothing less, because it was established very early he has an alternator.
glg

glg. "plainfully known that Randy has an alternator"? You might re-read his original post when he questions, "Or, is it the generator that's not charging the battery?". The characteristics of the two are significantly different as well as the physical set up of the systems. If he does not know the very basic step of putting a volt meter across the battery terminals, with the ignition off, and then on the battery clamps with the engine running, a very basic test, he might well not know whether he has a generator or alternator. Especially since the MGB was supplied with both over the years. Thus, he would appear to be a rather new or inexperienced owner. Hence, providing accurate information as to what he actually has is of more use than a "side note of personal history" which might tend to confuse. Use of terms such as the plug in connector to the alternator are much less confusing than terms such as "alternator voltage black box", something that does not exist. The "alternator voltage black box", known to most of us as a control box or a voltage regulator, was only used on the 1968 model MGBs with the Lucas 16AC alternator. Les
Les Bengtson

Guys,
I am a rookie, especially when it comes to the electrical issues. Any, and all, help is much appreciated. When it comes to Alternater vs. Generator, I was using them interchangeably, and I would have to study up to test either.
Since the battery had low fluid I added distilled water, and am charging the system. The car ran fine, so the poor performance was likely due to the battery not providing enough juice to the electronic ignition system.
I'll see if I can get the gen...alternator tested. And consider a new battery if this one doesn't hold a charge over the next few weeks. I only have a month or so of driving the B until the cold weather sets in and we go into the freezer.
Thanks for the help.
Sincerely,
Randy Olson
1977 MGB
1969 E-Type
randy olson

Les,

Boy, you got me there! Although this is just a public BBS to share experiences and insights, it's comforting to know there are a rarified few who know everything, and are not affraid to tout it.

As you've noted before, you are a highly aclaimed accademic. Perhaps I'll consider posting as though it were a doctoral thesis rather than my colloquial home boy manner of speaking.

Any future errors in my logic, terminology, process, proceedure, as well as other earth shattering minutia, will be corrrected, I'm sure.

Discertation not chat is, after all, the proper way.



glg

WOW!! this is realy funny stuff. Anyway, back to more relevant discussion.

Randy, If it were me and funds permited, I'd consider replacing the battery, alternator and perhaps the voltage regulator. Keep the alternator and regulator if they prove good, and start your collection of spares. (my car has a generator with a seperate regulator. I believe alternator systems can either be seperate or contained within the alternator itself, depending on year.)

I've been jokingly called a parts replacer and not a mechanic. It's true. I'm certainly not a professional but my car doesn't brake down either. I just figure that while one lucas part was frying, it was cooking the other components. Replace it all and you have a new charging system.
Clean your fusebox with a light abraisive while your at it.

I may not be 100% technically correct but at least you'll have a spare when you need it--and you will.

On that one warm May day in Ithaca, wouldn't you rather strap the wife in the B and head up the lake to the Glenwood Pines for a bloody mary than to be back on the driveway fussing with the car.

Proper Winter Storage is one of the most important things you can do for your car.
John Twist wrote a great article on this.
www.universitymotorsltd/winterstorage.doc
Love your car before the winter and she will love you in the spring.


I still think your alternator is bad. I was always told that when the alternator gives up the ghost, the batteries discharge,the plugs stop sparking and the car rolls to a stop. Sounds like what happened. Good luck

Paul
Paul Hanley

Good stuff, guys.
I'm charging the old battery right now. If that doesn't do it, I'll just buy a new one. And if that doesn't work I may have to take Paul's advice and head down to the Glenwood Pines for a cold one...I can almost coast there from here!
Cheers,
Randy
randy olson

Gentlemen,
I had a little more time to check on the battery tonight and run some of the tests suggested earlier.
I started the car and turned on the headlights, revved the engine...lights didn't get brighter or dim...there was no change. This suggests they were running only on the battery.
Then I checked the battery voltage. Stopped it was about 12.8 volts. Running it was around 12.5 volts.
It looks like I either need a new alternator, or need to run a few more tests to islolate the problem.
Suggestions?
Randy
randy olson

Randy. First, the basic description of your problem was classic bad alternator. Now, you have verified this. There are two possible things which could be wrong. First, the alternator was bad. Second, the plug in connections or the connection from the alternator plug to the starter are bad. Most frequently, when the plug is bad or the connections to the starter are bad, it also results in alternator damage. Thus, my recommendation is that you remove the alternator and have it tested. This can be done, normally for free, at any parts house. I would also check to see that the connections at the main starter terminal are clean and tight and that the plug is firmly inserted into the back of the alternator before removing the alternator for testing, but and alternator test, for both volt and amp output, is definitely in order. Les
Les Bengtson

Randy,

Very good to hear the progress you've made from your first post. That is the pourpose of this, and other, boards. offering help and assistence for nothing more than the joy and enthusiasm of being within the MG Octagon.

As for some previous posts, not to worry -- that was nothing more than a couple of old codgers, sitting around the garage, tossing sockets at each other soley because of a stubborn different of style of communication.It's nothing but petty BS.

What's most important is that you are on the way to enjoy a reliable MG.

Please have no hesitation in asking any questions.
glg

I pulled out the alternator this morning hoping to have it tested at the local auto parts stores, but none of the three I went to could connect it to their machine. The last store had an alternator for $86.
Then I went to Ebay and found the following:
60 amp Bosch alternator that is a direct replacement for many 34-43 amp Lucas alternators
Is this Bosch a better unit than the Lucas? Has anyone had any experience with Bosch's alternator?
Or, should I take my alternator apart and try replacing the brushes and anything that looks fried?
Decisions, decisions.
Randy
randy olson

Randy

You have to be careful with buying off of ebay. The problem you have with testing at autoparts stores is the connector. You will have similar problem with the bosch Im certain. If you are in a metropoliton area there should be an alternator repair place close by that can fix and test yours. A month ago there was a thread on the bosch alternator you are talking about. I seldom have ever found any thing that is claimed to be a direct replacement to be so. Let the buyer beware.

CW
CW Strong

Randy. My local Checker has the equipment to check out my Lucas alternators. They also have rebuilt alternators, by Autolite, which seem to be holding up well. There is much archival information on alternatives to the Lucas alternator. I have had very good service from the Lucas units over the years, but anything gets old and will fail. I have never found the need to change over to another brand myself. I did, however, change out the Lucas 16AC (34 amp) in my 68 GT to a Lucas 18ACR which made for a simpler system. Alternators can be checked, realtively easily, on the car. Les
Les Bengtson

I'm guessing here, but since you may be near watkins glen, there's bound to be an imported car shop in that neck of the woods.

I went looking in the Britsh Leyland, factory Workshop manual, (the one that bentley drastically condensed - 15 vs 40 pages on "Electrical System".

There are some very simple tests to make -- but far beyond my patience to type -- 5 pages on the Type 16AC alone.

Sounds silly, but the first check is "Is the fan belt tightened and are the connections tight and clean?"

Regarding E-Bay, what was the guy asking for that alternetor? A new one is about $100 --- what is the price for peace of mind? And, it'd probably be the last one you would need to buy or fiddle with.

How has the battery held up with addition of distilled water? It's very easy to say you just might have to bite the bullet and spring for a new battery and alternator.

But too, if you're mechanically inclined, Victoria British has all the innards to rebuild the alternator.
glg

This thread was discussed between 17/09/2003 and 20/09/2003

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