Electric fan sensor in head

[Iain T]

Rather than fit the sensor in a hose adaptor has anyone tried a Y piece or similar in the head so that the temp and leccy fan sensors can be fitted. If I can help it I would rather not cut and fit an adaptor in the top hose. I currently have a sensor that pokes in the rad but am not happy with it. 

Iain 

[Iain T]

In this location. It looks like a 5/8 NPT thread?

I have a Davies Craig controller and the sensor has a 1/4 NPT thread but not sure what the head and temp gauge sender is. 

 

[Colin Lindsay]

You could always try to adapt a thermostat housing, in the same way as early Heralds did.

I've tried three options in the past: thermostat housing drilled and tapped for sensor, waterpump housing drilled and tapped for two sensors, and a sensor in the bottom hose using a rally-car-style adaptor.

  

 

[Iain T]

Colin, I'll do more investigating. I thought the in line was supposed to be in the top hose? 

Iain 

[NonMember]

It's a matter of debate. You need to set a lower temperature threshold for a bottom hose sensor but it works fine as long as you do.

[Clive]

27 minutes ago, Iain T said:

Colin, I'll do more investigating. I thought the in line was supposed to be in the top hose? 

Iain 

Not necessarily, though more common. I think temp needs to be about 7 degrees lower in bottom hose, I used an 85 degree switch IIRC on my spitfire. 

I would be careful about position, water temp to the rad is a good call, but I guess the water pump housing should be OK. Trying to get my head around it.

[Nick Jones]

I was always taught that the correct place for the switch was on the radiator outlet side as that way it’s actually measuring whether the radiator needs help or not.

[68vitesse]

I have run my Vitesse for some years with a Revotec adjustable sensor in the bottom hose.

Regards

Paul

[Iain T]

For me it will be easier to use the Davis Craig sensor which has the plug to the controller. You just unplug the rad sensor and replace with the water sensor. I could fit this to either a hose adaptor or into the head or thermostat housing. 

I'll make a decision and just go for it, they will all work. 

Iain 

[thescrapman]

You can get a combined temp sender and fan switch that screws into normal sender location.

might be Fiat or Daihatsu?

[Peter Truman]

Attached two versions of rad fan switch install for a Spitfire and Vitesse, latter in top hose and uses stock in hose barrel nipple with 1/4in NPT thread, hoses are 2 modified Holden Gemini (Isuzu) that fit well.

The Spitfire one I modified an early Spit/ 2000 thermo cover (with boss) drilling out and treading 1/4in NPT it's relatively large dia so I had to be very careful to ensure I kept enough metal to hold down bolt hole, latter fitted to daughters Mk2 Spit for elect fan auto control works very well and we have 3 different ranged temp switch's for experimentation. I have a near new in perfect thermo cover that I've modified too to replace the photo one which has seen better days.

I hate those capilllary tubes that push under the hose to rad or thermo cover joint. 

[Colin Lindsay]

16 hours ago, Iain T said:

Colin, I'll do more investigating. I thought the in line was supposed to be in the top hose? 

Iain 

Bottom hose being longer means the unit is easier to fit - there's not really enough room in that short top hose - but requires a different, or at least adjustable, sensor to allow for the cooler water coming from the rad. I always adjusted mine judging by the temp gauge.

[Iain T]

47 minutes ago, Colin Lindsay said:

requires a different, or at least adjustable, sensor to allow for the cooler water coming from the rad. I always adjusted mine judging by the temp gauge.

The Davies Craig controller is fully adjustable and will also control two fans. I had trouble fitting one! 

As it's a grim day today I'll have another look and fiddle. 

Iain 

[68vitesse]

Agree with Colin, set mine to cut out as temperature according to gauge nears normal which shows water leaving the radiator is cool enough but not to cool.

Regards

Paul

[Iain T]

Using the bottom hose how did you run the cable? I have the controller sitting next to the battery and the cables to the fan and sensor are on the opposite side to the lower hose.

Iain

[68vitesse]

I ran the cables down nearside with rest of loom then across the round bar behind the front valence with the relay fitted to front off offside engine valence. Fitted a fused dedicated supply from battery through a relay switched by ignition with an override switch and run light.

The Revotec device is just the sensor unit to fit in the bottom hose and the relay for the fan so at it's simplest it just needs power and earth.

Regards

Paul

[Colin Lindsay]

3 hours ago, Iain T said:

Using the bottom hose how did you run the cable? I have the controller sitting next to the battery and the cables to the fan and sensor are on the opposite side to the lower hose.

Iain

I just ran the cabling in behind the horn bracket under the radiator. (Herald)

[Iain T]

Just gapped the rockers and took a general look around. I still think if I can get a Y piece to fit into the thermostat housing it would be the simplest solution. Does anyone know the housing thread size? 

This is my 'garage' .....before the lights go out! 

 

[PeteH]

The 13/60 currently has the stock engine driven fan. I am considering fitting a suitable electric fan, or even a pair, so this post is of interest.

Question?. Most advertised Thermo; controller "stats" appear to be a Fixed 80C (175/6F). Which is the same (+ or -) as the thermostat opening temperature?. If such (sensor) is in the lower hose, the fan will cut in potentially at a different Temperature?. As the Fully Open Temp; is shown in the Haynes manual as 200-205F. Is it potentially going to over cool?.

[Colin Lindsay]

2 hours ago, PeteH said:

Question?. Most advertised Thermo; controller "stats" appear to be a Fixed 80C (175/6F). 

Firstly do you need a fan? Are there current heating / cooling problems?

Secondly, don't go for a fixed temperature controller, go for a variable system. There's quite a wide choice, the link is to both a digital and a manual controller from a kit car builder website, but there are dozens available.

https://www.carbuilder.com/uk/cooling-fans#/pageSize=20&viewMode=grid&orderBy=15

[Pete Lewis]

On 14/11/2020 at 16:06, Iain T said:

Does anyone know the housing thread size? 

its one of these   ha 

https://www.smiths-instruments.co.uk/temp-transmitters

just need to convert a GTR108 generic to a smiths number  ???

 

[Iain T]

+1 for variable as where you place the sensor will require you to tweek the temperature. 

[Pete Lewis]

the thread is 5/8"unf x 18tpi   if that helps  

Pete

[Iain T]

Pete, I got as far as identifying the GTR108. Do you know the female thread size in the thermostat housing? 

Iain 

[Iain T]

You got there mid post! 

I'll punt around for a Y piece, the Davies Craig fan sensor is 1/4 npt, I'll need to find out what my temp gauge sensor is but should be doable. 

Ta