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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - starting/generator problems

The last several times I have been driving my 52TD, I have had problems starting the car. In all cases I was able to easily jump start it with a portable high amp jumping unit. I have searched through the archives and think I have a bad generator, but before I go through the steps suggested in the archive, I need help with some basic questions.As background, just prior to this problem, I was hearing a "rubbing" noise coming form the front end of the motor.

Now after I jump the car, the ammeter never goes positive when I rev the engine. It slightly goes negative and if I put on the lights, its goes negative greater. So this seems to tell me that the generator is not charging the battery.

After I jump the car, when measured with a battery tester, the battery level reads 12 volts. I am only able to start the car two or three times. Then the battery level reads 0 volts.

Doesn't the generator provide the power for the ignition system when the car is running? Is it possible that the generator is faulty, and just providing enough power to keep the ignition going and nothing else? Does the starter motor require much higher current than the ignition system?

Can I test the generator performance when the engine is running?

Any suggestions will be appreciated.

Mike


Mike Iandolo

Mike:

Sure sounds like the generator and/or regulator is not operating. A battery that is dead will still read 12v until a load is placed on the battery. Even a small light bulb is enough. Then the voltage will show a drop. It is possible that the generator is only providing enough power for the ignition. More than likely, jump starting recharges the battery enough to run the car for a while. The starter motor is the biggest draw on the battery. Starting takes more power than everything else combined. The car would run on flashlight batteries, once it was started.

The "rubbing" noise you describe sounds like one of the generator bearings has gone bad and the armature is dragging on the field coils. This will cause a no output condition. Also, worn out brushes will indicate no output. Generator output can be tested on the car, but a disassembly of the unit, inspection for worn or damaged parts, and bench testing is probably warranted.
John Masters

Mike -- A starter draws about 300 amps, the ignition about 3 or 4 amps. You have given us enough info to nail it down to the generator or regulator.

Disconnect the two wires from the generator, tape each of them so as not to short to the chassis, then put a quality voltmeter from the large terminal on the generator to the case of the generator. Jump start the engine and read the voltmeter, at 2000 rpm's you should see 2 1/2-3 volts. Now put a jumper between the two terminals of the generator, connect the voltmeter to the jumper and chassis, jump start the engine. Carefully raise the revs watching the voltmeter, it will go up to 20 volts very quickly. Try not to exceed the 20 volts. If your generator passes these two tests you are better than 90% sure the generator is OK and the problem is in the regulator. The only thing that could be wrong is the brushes are very worn and only make intermittent contact with the commutator and with no load the above tests won't show it. If it fails either of these tests the generator needs attention.

Keep us up to date on your tests and progress solving this problem.

Sincerely,

Bob
R. K. (Bob) Jeffers

Mike - Bob beat me to telling you how to test the generator, but I will add the following. The "rubbing" noise you are hearing may well be coming from the generator, the result of having the fan belt too tight or using a belt that is too stiff. A tight fan belt will result in the rear bushing in the generator to wear to the point where the armature will rub against the field poles. See the article, Keep Your Belts Loose under the Other Tech Articles on my web site at: http://homepages.donobi.net/sufuelpumps/ for information on checking the belt tension and part numbers for more flexible belts. Cheers - Dave
David DuBois

Bob,

I performed the two tests that you suggested. I think it passed both tests. The reason why I am not 100% confident is that in the voltage reading was constant or smooth. For example in the first test, at low revs the voltage was 0.4 and then it got to 2.5 to 3 volts, but even though I was holding the revs somewhat constant the voltage fluctuated around the 2.5 volt reading (anywhere from 1.7 to 3). On the second test, I voltage quickly climbed above 10 and as I increased the revs I was easily able to get the voltage to go to 20, but again, even though I seemed to be holding steady on the revs, the voltage fluctuated.

For what it's worth I am using a Sears digital multi-meter for these measurements.

Just as more background on the "rubbing noise". The noise started last weekend. Without knowing better, I thought the belt was slipping so I slightly adjusted the generator so that the belt was just a little more tight. The sound went away. The amount of time I drove after the adjustment and before I started having the problem starting the car was 45 to 50 minutes on two local trips. I don't know if I was driving long enough with the belt tight to cause the problems that Dave mentioend in his response.

So should I start focusing my attention on the voltage regulator? Could it be a faulty wire?
Mike Iandolo

Mike -- the test results say that the generator is electrically pretty good but may have 'sticky' brush holders. Also the bearing at the rear of the generator may be bad from a too-tight belt. Remove the belt and spin the generator with your hand, see if you detect any noise like the armature is rubbing. Better yet remove the generator and take the end plate off and look at the armature and pole pieces to see if they have been rubbing. Also while the end plate is off you can check the brushes to see if they are sliding in their holders easily and if they are long enough.
Cheers,

Bob
R. K. (Bob) Jeffers

Bob,

I removed the fan belt and spun the generator. It was spinning very smoothly --- no sounds at all. I then removed the generator and was able to spin it faster. Again no noise and it was smooth. So I expect the bearings are good. I then decided to open up the end and get a look at this. I have enclosed a picture, since the photo says it all. So, my next question --- where should I take this to get it rebuilt. Can any electrical shop do it, or do they need to be Lucas qualified.

Thanks so much for your help and advice.




Mike Iandolo

http://www.holcombedirect.com/browse.cfm/2,118.html
Call them and ask which one for sure. You need a new armature. They used to have a kit with bearings, brushes, and teh armature. I think they can rebuild it for you too. George
George Butz

You might be able to source one of these new ones made in India. I bought one of their new starter motors recently and am very pleased with it.

Cheers,

Paul.



http://www.sanauto.com/sanauto_products_starter_generators.php
Paul van Gool

You might look at http://www.ttalk.info/Holcombe.htm to get an idea about replacing the armature.
Bud Krueger

No sense in replacing a generator that can be rebuilt. One of the Holcombe armatures will do the trick. The front bearing, rear bushing and th ebrushes should be replaced along with the armature. It is a credit to the Lucas generator that it was still putting out the proper voltage with a third of the commutator segments missing. By the way Mike, both Bob and I neglected to say that the test of the generator goes better with an analog meter rather than a digital, but it looks like you did fine with the digital. Cheers - Dave
David DuBois

Mike,

Paul suggests that you can source a generator from India - if you buy one from Moss (who get their stock from India), check it carefully because the front and rear plates are not aligned in the UK batch. The result is that the bottom fixing holes are not aligned and this tilts the generator when fitted.
A flat edge placed across the generator pulley face produces a half inch gap at the water pump pulley face, so everything is under stress; fan belt and bearing.
To their credit when I told them about this problem, Moss in London said that they would modify the existing stock. I expect to get a suitably modified generator at the end of this week.

Mike
Mike Christie

Mike -- I recommend Holcombe (sp)Armature. I got a replacement armature from them along with the kit and am very pleased with it. While you are in there replace the brushes they have been beat up enough with those segments missing, Moss has them.

The ones from India are rated at 22 Amps which is better than original. I have no idea of the workmanship in them though.
Cheers,

Bob
R. K. (Bob) Jeffers

Thinking aloud here... I wonder if it makes sense to purchase the Holcombe armature as a spare. If the armature fails the alternative appears to be a replacement reproduction generator (Moss: $220). Other parts that may need to be replaced appear to be readily available and modest in cost.

Larry
Larry Shoer

"I wonder if it makes sense to purchase the Holcombe armature as a spare"

I purchased a couple of the Holcombe armatures as spares to have on hand, but am not sure that it makes good economic sense (other than hedging against the day that they are no longer made). Purchasing the armature alone, without purchasing the whole kit is more expensive if one does not have a core to send back. The armatures are a pretty sturdy item and a quick check of the comutator end by a good auto electric shop (Wilton Auto Electric comes to mind) can let you know if the comutator (where all the wear occurs) can be turned any further. Additionally, the armature is not a high failure item unless it is abused by the rear busing wearing excessively. In addition to the lost comutator segments on Mike's armature, I have had one rebuilt generator have all of the segments come loose, but in all the years I have driven the TD and an early MGB with a generator, I have not had any failures of the armature. I am sure that Bob has seen more armature failures than I have and he may be able to shed some light on whether or not one needs to have a spare taking up room on the garage shelf.

Mike - to answer your question, no, you don't need to take the generator to a Lucas trained and authorized shop to have it rebuilt. Any good (emphasis on good) auto electric shop can rebuild the generator for you (you will probably have to supply the armature yourself, only because of the tach drive extension of the shaft). Don't take it to Auto zone, Krugers/Shucks or other discount parts houses that als do repairs in the back room - they are not wht I would classify as a good auto electric shop. If you can't find someplace close at hand, sent it to Bob at Wilton Auto Electric. Cheers - Dave
David DuBois

"I wonder if it makes sense to purchase the Holcombe armature as a spare"

I purchased a couple of the Holcombe armatures as spares to have on hand, but am not sure that it makes good economic sense (other than hedging against the day that they are no longer made). Purchasing the armature alone, without purchasing the whole kit is more expensive if one does not have a core to send back. The armatures are a pretty sturdy item and a quick check of the comutator end by a good auto electric shop (Wilton Auto Electric comes to mind) can let you know if the comutator (where all the wear occurs) can be turned any further. Additionally, the armature is not a high failure item unless it is abused by the rear busing wearing excessively. In addition to the lost comutator segments on Mike's armature, I have had one rebuilt generator have all of the segments come loose, but in all the years I have driven the TD and an early MGB with a generator, I have not had any failures of the armature. I am sure that Bob has seen more armature failures than I have and he may be able to shed some light on whether or not one needs to have a spare taking up room on the garage shelf.

Mike - to answer your question, no, you don't need to take the generator to a Lucas trained and authorized shop to have it rebuilt. Any good (emphasis on good) auto electric shop can rebuild the generator for you (you will probably have to supply the armature yourself, only because of the tach drive extension of the shaft). Don't take it to Auto zone, Krugers/Shucks or other discount parts houses that also do repairs in the back room - they are not what I would classify as a good auto electric shop. If you can't find someplace close at hand, sent it to Bob at Wilton Auto Electric. Cheers - Dave
David DuBois

Jim Holcombe was a personal friend of mine. Before he started to sell the armatures as a kit he sold me 200 armatures. Moss took a great portion of those along with Abingdon Spares. Of those 200 I had zero failures. His son Ron is now operating the business. I also have used a few of his kits and am extremely satisfied. All you need is a core with good fields and the brush plate that is serviceable.
Check with them for the quality of your return armature. I think that they can rebuild it as long as it is straight with good bearing surfaces and threads.
I am no longer in business and have no connection with Holcombe Armature. However I would seriously reccomend their products.
They do have an 800 number so give them a call.
Sandy Sanders
Hudson Florida
Sandy Sanders

I want to thank everyone who responded to my questions on this thread. You have been a big help --- I would still be standing in my garage scratching my head if I had not gotten your advice. I am planning to follow up with the companies you referenced and I will also seek out local auto electric shops as an alternative.

I am hoping to prepare the damaged armature to ship out later this week. Since I have been driving the car at least five times a week for the past two months I will certianly suffer from withdrawl while I wait for the repaired armature and repair kit, and then try put it all back together. Based on my limited expertise and knowledge, you maybe hearing from me in a couple of weeks.

Once again, thanks so much for your help!
Mike Iandolo

"David DuBois, Bremerton, WA, USA ddubois at sinclair dot net

...The "rubbing" noise you are hearing may well be coming from the generator, the result of having the fan belt too tight or using a belt that is too stiff."

This is something that's often overlooked and it deserves the mention of something that's happened to me. Someone mounted my generator (dynamo) erroneously, it was something like half-an-inch back to where it should be. Results, I had to change the armature every few months or so! I was told that something must be wrong. Hence I used the mountings properly so that the pulleys were aligned, and now the armature has gone on for over ten years! What big damages a stupid thing like that can do!

Denis, 1950 TD
Denis L. Baggi

"Results, I had to change the armature every few months or so!"

The generator in our TD was mounted like that i our TD when we first got it. I never damaged the armature, but sure did in a lot of fan belts. Cheers - Dave
David DuBois

Quick update and funny story. I have determined that I also need to replace the field coils as well as the armature --- the commutator pieces that broke off damaged the coils, ripping off the insulation and breaking the wires. The only thing I would be reusing is the housing and the shaft (possibly). So I am now serously considering purchasing a new generator since I am not planning to restore this car for show competitions and my primary interest is having it as a fun driving car. I understand that the new generaotr may not be as reliable, but they do come with a 3 year warranty. Since I will be traveling over the next week, I will have time to second guess myself.

Now the funny story. Just to show you that sometimes we never notice what is sitting right in front of us in black and white. In addition to calling Holcombe, I also took Dave's advice and called Bob at Wilton's Auto Electric. So I reached Bob this morning and I launched into a lenghty discussion of my problem generaotr. When I told him that the armature was destroyed, he casually told me, "yeah I saw it". "On the bulletin board?", I asked. And before he could answer I realzied that the Bob at Wilton's was the same Bob Jeffers who expertly guided me through the test procedure summarized on this thread. And to make matters worse for me, he signed his full name on his messages. So, like an idiot, I didn't make the connection until we spoke. Well at least I was able to thank him again.

It's a small world, and for MG nuts, an even smaller world.
Mike Iandolo

Mike, I ran the Moss repro generator for 2-3 years on my TD. Other than using a spacer or two to align the belt (all three pulleys must be in line and parallel), no problem whatsoever. I rebuilt my original case/end plates at restoration, so I would save those for future use. Like Dave says, keep the belt loose. Pretty much everyone that looks at my car tells me the belt is too loose. I just shrug and say ok! George
George Butz

Since you're looking for reliability rather than originality, a change to negative ground and an alternator could do the trick. Probably around $100 in parts to do it. Not a lot of labor involved to change back some day, either (but you won't want to).
Tom

Mike - The great thing about this BBS is the number of real subject mater experts that are on it. I don't think that there is any other place in the world where there is such a collection of expertise than right here.

"Other than using a spacer or two to align the belt" There is supposed to be a 1/4" - 3/8" inch spacer between the front bearer plate and the front plate of the generator on all the T series cars to align the pulley as Denis and I found out the hard way (it is amazing what POs do to cars).

Swapping over to an alternator, as attractive as it is, will cost considerably more than $100 if you want to retain the tach drive that is used in our cars. It can be done. I believe that Jerry Felper in California modified some alternators to accommodate the tach drive gear box. I don't know if he is still doing the modification - if you want to check with him, contact information is at the end of the article Fuel Delivery Troubleshooting guide on my web site at: http://homepages.donobi.net/sufuelpumps/ For the ultimate alternator conversion (one that is in a standard Lucas dynamo case go to www.scparts.co.uk and look at the one for the early sprite/midget. It is really a neat package, but at last check the price was hovering right around $600 and that was when the dollar was much stronger against the British pound. Cheers - Dave

David DuBois

I did see an ad on the web for an alternator that looked identical to our generators, made in UK, for negative ground only, cost about $1,000.
Denis L. Baggi

On the TF my son-in-law and I are rebuilding, the generator was trashed. We used the Hplcombe Armature kit for bearings, etc. but then found that the insulation on the field coils was also disintegrating. Talked about getting a core generator for replacement field coils, etc. Scott had the idea of seeing if his local rebuild shop in Conyers, GA could redo the field coils and dropped the generator off for evaluation. Later that day the shop called and said he had found a set of new coils on the back shelf for the Lucas Generator. Scott dropped by to pick them up. Th guy handed Scott the coil box, he turned it over, it was made by Holcombe Armature Company!!!

It is interesting to note that many rural farm areas carry Lucas Generators and parts since they were used on Ford Tractors. Same as the T Generator but without the Tach drive. On at least one tour we got someone home on a Ford Generator found at a tractor store in rural Alabama!.
Sandy, I thought you might get a kick out of that.

Don H
Don Harmer

Don.
It was amazing what Jim Holcombe could find in his warehouse. I got a call from him when he found a big load of new shafts for TD generators.Apparently they had been in storage for a long time. He then had to locate all the segments for the cores. It was then that I purchased 200 complete armatures from him.
He was the kind of friend that you wish to never lose.
Those ford tractors also used the same cap-rotor and points as did the T's.
In the original shipment he included a strange gift. It was a new armature boxed from France.He said that if I could find out what it was I could keep it. Having lived in France for a few years I knew a few contacts. Sent photo and description. It turned out to be from a 1936 Simca.Sold it to a guy in New Zealand.
Sandy
Sandy Sanders

This thread was discussed between 26/05/2008 and 31/05/2008

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