Triumph 1200 water temp sender

[jagnut66]

Hi, 

Does the 1200 engine have a water temp sender unit?

If not where is the best location for one / what solutions have others come up with?

Many thanks,

Mike.

[Colin Lindsay]

It didn't have one as standard; certain models or special orders did and the sender was placed in the thermostat housing and came out of the top. The housing was blanked off for other models with a welded bolt.

If you can get hold of an early threaded housing you can use that (early Ford Fiesta models used the same idea and their caps are a straight fit, but equally hard to find) otherwise you can put the sender into the waterpump housing as in later models. It does mean getting hold of a later housing unless you're able to drill out the blanks in the Herald version (be aware early Heralds didn't have the blanks, they only came in about 1964 or after) but the two apertures mean you can fit both a temp gauge sensor and a fan controller if you utilise both, otherwise just leave one sealed.

You can also buy one of the Revotec hose inserts, originally designed for an electric fan control, but it will allow a non-standard temperature sender to be fitted. The bottom hose is the only one long enough in Heralds, so you'll have to experiment with the sender to find the correct range for whichever gauge you use.

[Pete Lewis]

it will also give good clues if you can find/use the rear of the head tapping  (not on all but its spare on many )

you must get the sender to match your gauge type

stabilised thermo bimetal ( slow needle movements) needs a voltage stabiliser and sender GTR108

wavy needle early type gauges dont need a VS but must use sender 121997

you cannot mix the two systems 

[Peter Truman]

Colin I like the alloy thermostat/water pump housing!

Ref thermostat covers with temp sender or switch tapped into them, there was another version fitted to some early 6 potters but also Herald/Spits I believe photo attached

[Colin Lindsay]

11 hours ago, Peter Truman said:

Colin I like the alloy thermostat/water pump housing!

Ref thermostat covers with temp sender or switch tapped into them, there was another version fitted to some early 6 potters but also Herald/Spits I believe photo attached

I've no idea where that one went; it was a Herald version but never used on any of my Heralds. It came ready drilled / tapped with no blanking plugs, but I suppose the original Herald versions could be removed and reused if the threads are the same. I do have one on the GT6 but only for bling purposes!

I like the side-fitting cap; that would help with bonnet clearance in the sportier models. I think that even in some of the models that used the top-mounted system the terminal had to be bent sideways, or the spade terminal had to be right-angled, to clear the bonnet?

  

[jagnut66]

Thanks for all the replies and information, I now know what I need to be hunting for and will start trawling.

Needless to say and as you have already advised me this may be a long hunt, if anyone is browsing and spots one please let me have a link to it.

I've always thought that water temp and oil pressure are the two basic gauges that we all need to be aware of what the engine is doing, plus hopefully be warned in time to avert any engine damage.

Best wishes,

Mike.

[jagnut66]

Well, having had a hunt I came up with these on the Rimmer site:

https://rimmerbros.com/Item--i-144297U

https://rimmerbros.com/Item--i-144297A

As you advised, the thermostat housings are like rocking horse poo (Triumph or Fiesta Mk1).

Anyway, I thought I'd have a look under my bonnet to fix my current set up in my head, before making a purchase........

And got a very pleasant surprise, it seems I am spoilt for choice! 😃

For simplicity I will undo one of the nuts in the water pump housing and screw in my sender there.

I say 'simplicity' but we'll see how easily it is undone..............

Best wishes,

Mike.

 

[DanMi]

having it in the water pump housing is probably better as that is below the thermostat, whereas putting a drilling into the thermostat housing would put the sensor after the thermostat. This is the setup on the later cars.

[Colin Lindsay]

You may find those very hard to remove, Mike - I've not ever tried it in earnest but the exploratory moves I tried years back took a lot of force. Be careful not to shear them unless you want to drill out and retap!

I just had a quick look at my spares - all are 1200 so none have yet been used for a sender; but the inner bolt ie the one closest to the cylinder head nut in the photo would put the sender into the water flow inside the housing; the other one is out of the direct flow, if it makes any difference to the readings. I couldn't find any photos of a Herald version but that's the way it's done in the Spitfire:

 

 

[jagnut66]

This is good news, as the inner stud is the one I was hoping to undo, though I note what you say. Some heat may be required then.

I am not worried about the heat damaging the pump itself, as I have a replacement, which I was planning to install when I flush the system out anyway.

I shall approach it with care.

As to the thermostat housing, what I meant was it is was good to have one with the position in place, although blanked off, as the housings without this seem more common and it gives me the option of drilling and tapping it for another car in the future, should I need to.

With this in mind what thread size is required for the tap?

Best wishes,

Mike.

 

[Peter Truman]

The thread in the Thermo Housing I used 3/8in NPT (18TPI) as that's what my temp switch was (Spit Mk2 Elect Fan control), & that's the largest hole/tapping I think is possible. Takes a steady hand to pilot the drill thro the boss and miss the bolt hole, or good machine shop tools! I did it by hand with the trusty Dewalt

I like those electric bolt heaters the TV car maintenance crews use to just preheat the bolt head or nut to red hot then the nut/bolt just comes out, wonder how much they cost?

Colin I notice your GT6 thermo housing is showing it's age esp on that beautiful Alloy water pump housing a Co. in NZ on Trademe is selling NEW ones at NZ $187, hope this advice doesn't break any rules.

 

[jagnut66]

1 hour ago, Peter Truman said:

The thread in the Thermo Housing I used 3/8in NPT (18TPI)

Thanks Peter.

[Colin Lindsay]

10 hours ago, Peter Truman said:

Colin I notice your GT6 thermo housing is showing it's age esp on that beautiful Alloy water pump housing a Co. in NZ on Trademe is selling NEW ones at NZ $187, hope this advice doesn't break any rules.

That's a spare, Peter, it was mocked up using odd parts before being fitted for an article in The Courier many moons ago - the GT6 now has the alloy housing plus a new stainless water-pipe take-off and a far better thermostat housing. Well spotted - it's in poor condition but still sitting on my shelf as I can't bring myself to throw it out.  

[Jon J 1250]

Hi all,

I thought I would pick up this old thread as it seems relevant to my questions.

Being part way through my project to re-commission my one previous owner 12/50 (a car I bought as a student in 1995), I have got to the cooling system.

I have had success in flushing through the radiator, pressure testing it and have repainted it.

Now I need to get to the thermostat to flush the block through, which bring me to the housing.

The car has what at best could be described as a bit of a Heath Robinson installation of a temp sender, the probe is clearly too long for the space, so a block of aluminium has been roughly cut and sandwiched in between the water pump housing and thermostat housing. In some respect it's part of this car's charm as it must've been done by the original owner some 50yrs ago, but I think I'd like to improve it somewhat.

Can anyone advise what the most sensible solution is, can I buy any old Smiths gauge from Ebay/autojumble and expect it to work, also what size is the thread in the thermostat housing, should I blank it off and put a probe in the water pump housing? so many questions?

[Pete Lewis]

theres nothing wrong with a capillary operated  gauge they can??    be very accurate

the stag with it stuck in the top is it will block the thermostat form opening as the valve disc rises inside the Hsg.  hence a spacer 

you could do that on a 6 cy and may be tight on a spitty bonnet claeance 

you could add the capiliary to a side tapping   some need an adaptor to seal the bulb on the end 

in general they  are on triumpf all 5/8 unf threads 

any gauge will work if you wish to change to electric but you must match senders with gauges  there are two distinct designs   voltage stabilised and  moving iron non stabilised 

both use a very diferent sender or you get crazy reading to confuse you more 

a non stabilised gauge needle will wagg about if shaken      an  thermo bimetal  VS one wont and needs a VS to control a stable gauge voltage 

 

pete

[jagnut66]

On 25/07/2021 at 16:20, Colin Lindsay said:

You may find those very hard to remove, Mike

I'm very pleased to say that I got lucky and after a little initial stiffness it wound straight out. I cleaned up the thread and my new sender wound straight in. Result. 🙂

Best wishes,

Mike.

 

[Colin Lindsay]

Brilliant. It's always great when something works.

[jagnut66]

A long handled rachet is a big help, gives you extra leverage.

Best wishes,

Mike.

[Herald948]

19 hours ago, Jon J 1250 said:

Hi all,

I thought I would pick up this old thread as it seems relevant to my questions.

Being part way through my project to re-commission my one previous owner 12/50 (a car I bought as a student in 1995), I have got to the cooling system.

I have had success in flushing through the radiator, pressure testing it and have repainted it.

Now I need to get to the thermostat to flush the block through, which bring me to the housing.

The car has what at best could be described as a bit of a Heath Robinson installation of a temp sender, the probe is clearly too long for the space, so a block of aluminium has been roughly cut and sandwiched in between the water pump housing and thermostat housing. In some respect it's part of this car's charm as it must've been done by the original owner some 50yrs ago, but I think I'd like to improve it somewhat...

 

That actually appears to be a decent installation for a capillary type gauge, with the necessary adapter for the bulb-type sender. Also, with that adapter, it probably avoids the one potential problem with the sender in the thermostat housing, which is that you really need to have a "flat-top" bellows-type thermostat. Modern thermostats would foul on the sender unless some sort of adapter or spacer is used. It's not always easy to find those older bellows thermostats these days.

BTW, temp gauges were always fitted at the factory for North American-spec. Heralds.

[jagnut66]

17 hours ago, Herald948 said:

BTW, temp gauges were always fitted at the factory for North American-spec. Heralds.

Would be very interested to see a picture of your dash, to show the 'North American-spec' instrument / gauge layout, including the temp gauge.

Best wishes,

Mike.

[Colin Lindsay]

I've just looked at a number of US Heralds in 'For Sale' Ads and they all appear to have the temp gauge at the 10 o'clock position to the speedo. I'm assuming this was the factory position?

  

[jagnut66]

Interesting, looks like a different veneer option too.

Best wishes,

Mike.

[Colin]

Hello Mike & fellow enthusiasts;

Mike . . . congrats in removing the water pump nut. I too, should like to be furnished with water temp and oil pressure info inside the cockpit (1970 1200 Herald saloon).

However, I'm the type who doesn't have the expertise (or relevant equipment) to re-thread anything should it all go horribly wrong on a removal attempt!

I've discovered that when trying to remove old and previously unmolested nuts, working them as if to tighten to begin with (obvs after loads of WD40 has soaked in for days), can work wonders and although counter-intuitive, often works well.

My question to you is this:- what type of sender did you acquire to fit into that aperture (5/8s as Pete Lewis said??) and from where is it available please? From this point on, what variety of sender was it (again, Pete Lewis describes 2 types) and was the relevant gauge easy to find, and connect to?

I suppose my 3rd question would be; what kind of temperature ranges should a reasonably healthy engine display at the gauge . . .

Nine months have dragged by and I am hoping to get my Herald back from my metal worker before too long (bonnet and front wheel arches rebuild, front sidelight areas repaired, wheel arch repairs, tread plates renewed, rear wing 'shoulder' repairs etc etc), which means that I shall mostly be back to ensuring her mechanics are as sound as can be given she's on 147k miles, original engine (still going strong).

At which point I can hopefully follow Colin & Pete's instructions for flushing the cooling system out, as he spotted congealed gunge in the thermostat housing and, the heater has rarely put out any significant heating - which made Winter in rural France when I was there precarious to say the least! 

Looking forward to hearing from you.

Best,

Colin

[jagnut66]

9 hours ago, Colin said:

what type of sender did you acquire to fit into that aperture

Hi Colin, 

Here you go: https://rimmerbros.com/Item--i-GTR108

I also recommend you change these: https://rimmerbros.com/Item--i-GTS104 https://rimmerbros.com/ItemRating--i-GTG103

I had my radiator and heater matrix recored, as they had been fed plain water up to the point I flushed it all out and they were both in a right state, the heater matrix was completely blocked up.

If yours are too I recommend you source a company near you and do the same, preventative maintenance and far cheaper than a cooked engine. 

Best wishes, 

Mike.

[Colin Lindsay]

On 27/08/2021 at 09:51, Jon J 1250 said:

The car has what at best could be described as a bit of a Heath Robinson installation of a temp sender, the probe is clearly too long for the space, so a block of aluminium has been roughly cut and sandwiched in between the water pump housing and thermostat housing. In some respect it's part of this car's charm as it must've been done by the original owner some 50yrs ago, but I think I'd like to improve it somewhat.

I spotted this one recently; a very original 948 saloon but the sender is also quite long. I'm wondering, however, looking at yours, if that's more of an adaptor than a spacer - perhaps the threads were different?

Early transmitters were part number 121997 but I can't find a photo of an unfitted item.