MG T-ABC

On a TC I'm intrigued as to why some cars had a combined oil/temperature gauge and some separate. If there was a obvious change when did this take place?

I'm pretty certain that none of the TC's ever had a combined oil/temp gauge fitted at production time until the introduction of the TD; when I'm sure the option to change became available. Since then it makes sense if you can along with a water temp gauge to include them to provide additional awareness ... but not for concours, just a oil pressure and ammeter gauge.

My comment was instigated as a result of the number of adverts online indicating that the combined unit was used in the TC. Whilst I now understand whilst it is possible to use it is not original.

Definitely not original. TC had no temperature gauge from the factory. Installing a dual gauge is a way to get a temperature gauge without drilling a hole in the dash for a proper standalone gauge.

Steve Simmons wrote: ↑

Wed Dec 01, 2021 10:30 am

Definitely not original. TC had no temperature gauge from the factory. Installing a dual gauge is a way to get a temperature gauge without drilling a hole in the dash for a proper standalone gauge.

It has always intrigued me that there was never a water temperature gauge of any kind fitted to the TC and I have wondered why this was.? Could it be that MG were so confident in Claude Bailey's modern design that they doubted it would ever be needed?

It surprises me also. It has those expensive chronometric gauges, but no temperature gauge. I'm sure the dealers sold lots of Motometers.

Steve Simmons wrote: ↑

Wed Dec 01, 2021 1:59 pm

It surprises me also. It has those expensive chronometric gauges, but no temperature gauge. I'm sure the dealers sold lots of Motometers.

My theory is that the sophisticated design of the cooling system was so impressive that dealers could say that it was one less thing the motorist had to worry about. With the traditional thermo syphon set up, it was quite normal for cars to boil their radiators especially in warm weather and on hills. The Claude Bailey design with pump and thermostat (and it's ability to control a bypass) theoretically made overheating a thing of the past. I can't think of any other reason for not having a gauge.

I understand that modern reproduction "skirt" type thermostats are not as reliable as the original units (I may be wrong?) so I am fitting a temperature gauge. I have read somewhere that they were an optional extra for those who felt it was needed.

The strange thing to me is that TC4902 which was supposed to have been in store since 1956 before I bought it into the UK both had as a temperature gauge but also has the facility to fit the sensor in the top of the radiator. This obviously could have been an original owners` choice but certainly a lot of trouble to go to. However I do recall a previous TC owned some 20 plus years ago did have a motometer but can`t remember whether it also had a temperature gauge. The mysteries of owning a MG.

I had an interesting discussion with a mechanic who felt that a better place to fit a water temperature sender unit was in the bottom hose. HE argued it was knowing the temperature of the 'cooling' water that was more useful. .He also pointed out that if water had evaporated or leaked from the header tank the sender would not be reading water temperature at all so the gauge would be misleading.

Food for thought perhaps?

Interesting comment Ray -did you make that change or indeed as anyone else?

jddevel wrote: ↑

Thu Dec 02, 2021 6:25 am

Interesting comment Ray -did you make that change or indeed as anyone else?

As usual, I heard about this AFTER I had done the job. I had bought and fitted the special connector and sender to the header tank. To be fair, it wouldn't take much to change it but I was asking myself the same question. Having always seen the sender in the top I assumed that was how it should be. On the other hand, just because something has always been done in a certain way, doesn't mean it can't be done differently.?

The more I think about it, the more logical it seems. We know the temperature can't go over 100 degrees C....and what we really need to know is the temperature of the water which is going to cool the engine. If that is too hot you have a problem!

I expect someone more knowledgeable than me will have an opinion.

To me the most useful place is at the cylinder head. I would rather know how hot the hottest area of the engine is. Doesn't matter how cold the water coming out of the radiator is, and whether it's a tiny radiator or a huge one will read differently also. I have my sensor in the top tank of the radiator. This tends to be a few degrees cooler than the cylinder head, according to an IR thermometer. So I have a pretty good idea of how hot the engine truly is.

My cunning plan is to install two modern electric sensors. One in the top rad hose and one in the bottom. Be interesting to see the difference whilst readily being able at minimum cost to return to original if so required,

You can use an IR thermometer on the top tank and bottom outlet, which will give you the same reading without having to install two gauges / sensors. Not while driving obviously...

I appreciate that Steve. Just thought it would be interesting to monitor whilst actually driving

I agree; the cylinder head is probably the best place because it will warn you at the gauge if the thermostat has seized shut and not allowing water into the radiator. Unfortunately, having the sensor in the header tank will not show the high temperatures being reached on the other side of the thermostat.

I remember now what the mechanic said about having the sender in the bottom of the radiator. He opined that we should be thinking about it the other way round. What that means is... should the temperature not reach what is normal i.e. stays in the cold range, it could indicate a faulty thermostat not allowing the over heated water to leave the head.

I can see his point... but old habits die hard. Agreed ?

Indeed. Having just having had the rad professionally flushed and repaired (and the engine rebuilt) it should hopefully be working at maximum efficiency.

jddevel wrote: ↑

Fri Dec 03, 2021 12:57 am

Indeed. Having just having had the rad professionally flushed and repaired (and the engine rebuilt) it should hopefully be working at maximum efficiency.

I was extraordinarily fortunate to find my rad to be in excellent condition. What a marvellous piece of engineering it is! Made from copper and brass all expertly soldered together and built to last!!

My TA has a Motometer with a very interesting marking feature, a Packard radiator and a biplane. I recently found the same one on a 1916 Packard racing car in a museum. The museum had others with various car emblems printed on them. I like it and will keep it as part of the car's mysterious dark history.
I did some research. Motometer and it's competitors date from about 1914-1920, when the need for measuring water temperature apparently became a common concern in the motoring world, and several designs were patented and put on the market. Stewart-Warner had one with a needle like our familiar dashboard gauges, but this one had a bi-metallic spring mechanism inside and fitted in the radiator cap.
I have not yet found when the Bourdon tube design hit the market, but it was presumably in response to drivers wanting to easily see the temperature, without having to try to shine a light on the radiator cap.