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MG Midget and Sprite Technical - Electric Fan Thermo Switch Temp?

At the moment I have an electric in front of rad pusher fan controlled by an adjustable with one of those sensors that is either inserted under the end of a water hose or through the radiator.
Neither of these alternatives is ideal - so I'm looking to buy an Aluminium Hose Adaptor (https://www.merlinmotorsport.co.uk/p/32mm-aluminium-hose-adaptor-ha32) with a tapped hole for a brass fan switch (https://www.carbuildersolutions.com/uk/fan-switch-97c85c-m14-x-15-brass).
I suspect that the ideal position for the hose adapter would be the outlet hose from the rad - but as I don't have access to the car at the moment (in another country) I'm not sure that the bendy nature of that hose would allow a decent fit.

Question 1 - If it does fit, what temp range should I aim for, bearing in mind that this is for a standard 1500?

Question 2 - If I have to use the the top hose (exit from engine to rad) I suspect that a different temp range stat would be needed.

Does anyone run a similar setup and have they any recommendations for the two different setups?
Tony Wood

Do you still have the engine driven fan?
Nigel Atkins

i put a boss in the radiator it takes a screw in thermostat, just soldered one in an easy job thought it looked better than the one in the hose.

mark heyworth

Nigel - at the moment yes the engine driven fan is still attached, but can of course be taken off which would be ideal.
Mark - I like the simplicity of the brass boss soldered to the return side of the rad - but how easy is it to solder on without b---ering up the rad? A soldering iron would not work surely. I have a small camping gas blow torch for home plumbing soldering - would that do the job?
Obviously a hole has to be made in the return side of the rad - is this drilled first with the boss soldered over it or is the boss soldered and a smaller hold drilled in the middle of the boss? Looking at your photo it looks as though the hole you made was indented so that part of the body of the boss was pushed into the hole and was a tight fit before you soldered it. Any soldering tips will be gratefully received!
With regard to switch temps does 87c/82csound about right?

Actually I've just noticed that there is a ridge on the boss so that the narrower part of the boss just fits in the rad hole (provided it's the right size)!
Tony Wood

I just used a plumbers blow torch and plumbers solder, just used a hole cutter and tinned both the radiator and the boss and it soldered in easy as long as you keep everthing clean and use a good flux, I had to try 2 different thermostats before I found one of the right temp.It might be a bit of over kill but i fittime delay of 3 min run on when ignition off as well, mind you it has not been on for a long time .I short out thermostatic swicth to check fan runs as part of service think thats just me being over cautious .
mark heyworth

Tony,

this is what I have - similar to what you're thinking in your first link
http://www.revotec.com/acatalog/Electronic-Fan-Controller-Hose-Fitting.html

Just seen the price for the controller - yikes - more than I paid for a complete kit for a classic Mini on ebay!

The unit is adjustable for temperature.
Jeremy MkIII

.....controlled by an adjustable with one of those sensors that is either inserted under the end of a water hose or through the radiator. Neither of these alternatives is ideal

Why ever not pray? Simple, cheap, reliable. Your slegdehammer is working overtime in cracking those nuts :)
Oggers

Tony,
I've been holding off on this thread hoping I'd remember what had been covered in an earlier thread about where best for fan switch and temperature range but I can't remember much.

I do remember and have checked a previous post of mine, the 'water' stat if an 82C start to open at 82C but isn't fully open until 92C. IIRC there can be a 2C(?) manufacturing tolerance so the range could be 80C-90C or 84C-94C (or even perhaps 80C-94C?).

So that's a possible temperature range at the water stat position in the coolant system.

I think it's generally considered to have the fan stat as close as possible to where it'll be hottest, top hose or nearer head.

I'm not sure how long lasting and reliable these relatively inexpensive fan switches are, no doubt you already know or done the research.

I'd recommend a fan switch with a variable range (I have the expensive Revotec) that way you have options for its positioning and you can experiment with the setting suitable to your particular car.

Ideally (to me) you'd remove your engine driven fan and have an electric puller fan fitted other (engine) side of rad as that'd be more efficient I believe (and might have more room for a large diameter fan?).

Main thing of course is to have all of your cooling/heating system in good working order and fully serviced both water and oil.

I hope some of this helps, wish I could remember more, you could try searching the Archives as I'm on a miss day with them.
Nigel Atkins

Oggers, I agree with you entirely - if it's cheap, works and reliable then use it. However my existing thermo sensor when inserted into the top hose leaks - despite using the small finned rubber pad with the slit in to make a watertight joint! Doing up the hose clip tighter does not do the trick.

Any suggestions - possibly some plumbers PTFE tape. The hose is a new one so should not be a factor and I've changed the old Jubilee clip for a more modern double wire clip. Neither did the trick - so I must be doing some thing wrong!
Tony Wood

Tony,
you're not over tigtening the clip are you, the rad outlet is nice and round with no dinks or dents.

Have you seen the Norma GBS clamps, no welds to brake either unlike the much favoured Mikalor.
Nigel Atkins

Nigel - I'll have a look at those clamps you mentioned. I'm slipping the thermo unit with its thin metal tube into the hose at the aluminum thermostatic cover end which I cleaned up with a bit of emery cloth. Perhaps a bit of PTFE next time with a different type of clamp - which will be after I manage to get the cam timing sorted - the small sprocket has lost its timing mark, which is a pain in the elbow!
Thanks to all for your input - it's nice to have enthusiasts input especially in my neck of the woods.
Tony Wood

Tony,
I don't see what help PTFE tape will be so wouldn't use it.

Is your current thermoswitch adjustable?

Not on Spridgets but I had a couple of Kenlowe kits with probe and rubber mounting pad that went into the rad top hose, rad end, I can't remember any problems with the installation or working, adjustable thremoswitch.

Photo below of my Rover P6B installation, thermowsitch circled and wire to probe arrowed.


Nigel Atkins

Just found this, the probe goes into the radiator via the top hose outlet, not in the top hose as I seem to be suggesting in my last post.

I've lifted this from some instructions -

It will then be necessary to put a 'U' bend in the copper pipe so that the bulb is pointing into the radiator.
Take great care at this point because the copper tube on this unit is delicate and can become work-harden and will then break quite easily - once broken it has to be replaced and this can be quite expensive.
Place the rubber block supplied onto the top outlet of the radiator, then put the [thin part of the] copper tube in the grove of this block. Carefully slide on the top hose and fasten the hose clip.
Make sure at this point that the rubber block has not moved and there is a good seal between the hose, copper pipe and radiator outlet.

HTH

Nigel Atkins

Tony

Clean up the outsude of the rad stub with emery cloth/wet &dry and yes try the PTFE tape. Obtain a SS quality hose/jubilee clip where you can obtain good all-round circumferential purchase, and one you can tighten up - firmly! It does need to be tight. At a strech your hose may have become brittle - so consider replacing that if necessary. If all fails, perhaps try somewhere else? Mine is at the water pump discharge where the metal is reasonably thick to get a good firm clampping force for the wire underneath the hose. Don't believe it matters where you put it if your sensor is adjustable over a reasonably wide range. Bit of trial and error as to where it is set, but err on the side of caution. The numbers on the sensor dial are often just a guide by the by.






Oggers

The bit of the radiator that forms the stub for the hose to attatch to is just a short length of thin walled metal tube - possibly brass. Overtightening of a hose clamp onto this can deform it and crack the joint where it is solderd into the radiator. So whilst you need to get a good seal, do be careful about just how tight you do up the clamp!

How do I know this?
GuyW

Yeap as I put I'd got a fan switch with a variable range that way you have options for its positioning and you can experiment with the setting suitable to your particular car and agree use the numbers/markings on the switch as a guide.

Both Mark and Guy make very good points the clip wants to be firm but not overtighten, I've always found they need a slight nip up after a couple of heat ups and cool downs with a couple of drives (for the vibrations(?)).

I've found good quality Jubilee (style) clips to be fine, I use s/s but they are expensive, I'd not suggest you'd need the Norma ones but offered them as an alternative particularly on perhaps stat housing or pump outlet as the clips have a wider band.

As can happen on occasion I disagree with Mark on the need for PTFE but as often happens I could be wrong, I just can't see the gain over, perhaps unlikely, potential loss.
Nigel Atkins

Sorry,
>>Yeap as I put I'd got a fan switch ...<<

should have been - Yeap as I put I'd *go for* a fan switch ...

Once again I've got a keyboard that can't speak or write correctly.

Or it might just be me got it wrong again. :)
Nigel Atkins

Correct Guy - partially the reason why mine is on the water pump discharge stub. PTFE tape may be used to wrap around any stub to achieve an improved joint when used with a flexible hose. It tends to mitgate surface imperfections.
Oggers

This thread was discussed between 27/06/2018 and 30/06/2018

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