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MG TD TF 1500 - Red warning light stays on.

Hi I've recently bought my first classic car a 1954 mg tf and this light is staying on but the mechanic says the dynamo is charging can anyone give me some advice on this please? Thanks Derek
D Barnett

The red light is the generator light, what does the ammeter do when you increase the RPM above 1200/1500RPM.

Is he an old auto electrician?

Peter
P G Gilvarry

Hi Peter thanks for your reply. The ammeter just moves slightly to the left and goes back and forward. Sometimes the light flickers on and off. He is a mechanic who works on old classic cars and was recommended to me.
D Barnett

Derek,
if you haven't got a paper printed copy of the relevant 'Operation Manual' (Driver's Handbook) then you can download this shared PDF. - https://drive.google.com/file/d/0BxisXBEpc-IWLWwzcVVjeVBRZ2c/view

Do bear in mind things like oils have changed a lot and improved over time and some modern electronic stuff can be a good improvement to performance and reliability, like a fully (bottom as well as top part) electronic distributor, not all of the servicing requirements needs to be so very frequent with modern materials and parts. On the other side there are plenty of modern made piss-poor parts, if it seems cheap then it probably is.

Get plenty of reasonable length drives in to free the car up, and you to get used to it and see what priority anything needs doing. I always recommended having a staged 36k-mile service on the car in between driving it. Attending to brakes, tyres, steering and suspension first of course. Cleaning/flushing/renewing all the fluids including those left festering for decades like in the gearbox and rear axle.

Do yourself a favour and have a good battery kept in a good state of charge with all cables, wires, earths and connections all in good condition and clean, secure and protected. A low battery and poor connections also won't help if you have or issues elsewhere.

As it's your first classic don't fall for the idea that it needs to be treated like the vicar's maiden aunt's sunny Sunday car, highly polished but slow, unwieldy and unreliable. It's only the owners that make them and keep them that way.

Drive it as regularly as you can and learn to drive it in a spirited fashion it was designed for.

Regular driving, service and maintenance will have it running better than the occasional run out and long periods of inactivity and hibernation. Much many more better driving opportunities in late-autumn, winter and early spring than the usual 'driving season'.

Good luck.
Nigel Atkins

Hi Nigel thanks for the reply and yes I fully intend to use the car as much as possible and enjoy the driving experience. I have the original manual that came with the car and plenty of spare parts. It is a one owner car from new which has to be a record.it has been garaged for a few years and probably just needs to be driven regularly. Thanks again.
D Barnett

Derek,
you certainly must have a very rare purchase nowadays with a one-owner car.

Yes a good few drives in quick succession will help to loosen the car and find any issues that need attention and their priority, just more driving can resolve some and help establish those you can live with for a while or accept fulltime.

Being garaged for a while does mean it'll need a lot of checking and coaxing. Even the grease could be crusty and dusty. Very important of course are the condition of the brakes and braking system (which includes the tyres) which can age and harden with lack of use, the steering system (which includes the tyres), the suspension system (which includes the tyres).

You see what I'm getting at, the often overlooked ageing and hardening of tyres through age and lack of use, which regardless of tread depth left on them severely compromise safety and the performance of the above mentioned systems.

Unless you've had the opportunity to drive a good mechanical example of the model, which often aren't the shiny little used examples, it's difficult for you to know how well yours does or could or should go, but once you've driven it regularly and carried out some servicing and maintenance you'll no doubt be able to tell the improvements from just doing that and know more about your car.

You can get lots of good information from here, there are plenty who really know the model (not me I only know general non-technical things). They'll be able to tell you what's realistic to expect rather than "they all do that / are like that / can't expect more".

The T-owners are also more willing than some of the later MG models owners to take advantage of suitable modern improvements and not stuck in the mindset that all of the old stuff was always best and should be stuck with.

Of course now photos are wanted of this car. 🙂

If you want to you can add your details to your 'Vehicle profile' and make it viewable to others too.

Just the right time of year to start your adventure too, get you ready for those fabulous autumn and winter driving opportunities when the good runs aren't so clogged with those drive it for a day classics take it a bit too steady or waiting for recovery. 😋
Nigel Atkins

The operation of the generator warning light is very simple, it simply compares the output of the generator to the battery voltage.

Ignition on, engine not running, light will be bright.

Start the engine, the light might be a little less bright.

Increase engine speed, as g3nerstor output increases towards battery voltage the light gets less bright until it extinguishes.

The ammeter at idle would be right of center , as you increase RPM it will move left, and it should remain there, even if it jumps a bit.

I have a simple 2 lead test lamp thst I made, one side goes to live side goes to the live side of the battery, the other to the big terminal of the generator. It will mimic the description above.

Your ammeter going left is encouraging, the light should extinguish when it does.

Peter
P G Gilvarry

Peter,

My ammeter indicates a charging condition when needle is pointing right of centre (+) and obviously, discharging when left of centre (-), such as during idle, or when the headlights are on. This is the opposite to what you are suggesting.

Is this wrong, or do I have the ammeter wired up in reverse?

David
David Padgett

An other reason could be the change of dynamo polarity.
W_Mueller

My ammeter also moves right when charging and is marked "+" on the right. All the other TF's in my Octagon Club group move left and are so marked "+" to the left.?????
Which was original
Ray TF 2884
Ray Lee

On my 55 TF, left is + or charging.

No reason to suggest that is not normal.

Peter
P G Gilvarry

It is just me and David then, strange.
Ray TF2884
Ray Lee

I found out why.
I have a YB ammeter fitted which was on the car when I bought it in 1974.
It is the same except for being reversed, why they would buy 2 different gauges is a mystery.
Ray TF 2884
Ray Lee

Apologies. I was thinking TD, not TF.
David
David Padgett

Right, just me then :-}
Ray
Ray Lee

Check the condition of the brushes in the dynamo, also check to see if the armature needs cleaning. PJ
PJ Jennings

As the light only flickers rather than staying on based on my 30+ years experience of using various classic cars as dailies, rather than any technical knowledge, I'd strongly suggest driving the car more and see if it improves, gets worse or stays the same, and then decide what to do.

The dynamo doesn't operate in isolation and the whole car has been garaged for a few years so all systems need to be brought back into literally running, rather than static, condition, and order.
Nigel Atkins

The +...0...- meter face! Fascinating, intriguing. I'm a retired EE who has been looking at meters for nigh onto 80 years. I have never seen an electrical indicating meter with that display. Not even from the days of 'Current' vs. 'electron' flow.
I wonder if it's unique to automobiles with positive earth grounds. The current that it wants is indeed negative. It would seem that we intuitively view something to the left of zero as undesirable and to the right of zero as what we want.
Could somebody please post an image of such a meter? TIY. Bud
Bud Krueger

Taken at idle on first run after winter, it the best shot but you can see -ve to the right.

In the operation manual for my TF it shows -ve to the right.

I agree, usually left is the less desirable indication and to the right is perceived to be good.

Peter


P G Gilvarry

Taken at idle on first run after winter, it the best shot but you can see -ve to the right.

Peter


P G Gilvarry

From the drawing in the 1952 Operation Manual I take it as the D to the extreme left represents discharge. Obviously different gauges were used over the years.






Nigel Atkins

Bud,
I bought this on ebay with + on the left and am converting it to Lucas
with + on the right. I had never come across it either and I am also a retired EE.
Regards
Declan





Declan Burns

The usual convention is that Clockwise is increasing and anti-clockwise is decreasing.
When the indicator is pivoted at the bottom this leads to the Plus being on the right.
However when the meter is turned upside down, as in the TD, then the Plus would be on the left.

I agree this can be confusing to some, and perhaps this is why it may have been changed.

OTOH, I have a set of bathroom faucets, the hot increases clockwise and the cold anti-clockwise. It balances things ascetically. I am continually turning the cold on full instead off, splashing water over everything.


Jim B.
JA Benjamin

Staying OT,lever arm Taps (faucets) are handed L&R but standard taps not.
I worked in hospitals and this caused loads of trouble
when wrongly fitted.
Ray TF 2884
Ray Lee

Peter, is there a plus sign (+) at the other end of the scale? Bud
Bud Krueger

Since we have drifted to faucets I agree with both Jim and Ray. I bought a faucet set that normally has levers but with cross handles. No longer did the lever model of swinging the handles together make sense for the hot water side. So I had to buy another cold water interior valve for the hot water side so it followed the "righty - tighty" rule. :-)
Christopher Couper

Bud, I will check later, but at idle it sits right of 0 and deflects left with increase in RPM so it is connected correctly and functioning IAW expectations.

SU fuel pump causes deflection to the right.

Peter
P G Gilvarry

I would also make sure the points in the control box are clean and not pitted, which could cause fluctuations. PJ
PJ Jennings

Bud,

Here is the shot showing +ve to the left.

When I bought it with +ve Ground it worked correctly, I reversed it as part of the -ve ground conversion.

I have an ever so slight off-center when stopped, and battery disconnected.

Will have it rebuilt some day.

Peter


P G Gilvarry

This thread was discussed between 15/04/2021 and 25/04/2021

MG TD TF 1500 index

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