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Author Topic: Davies Craig Thermatic fan Install  (Read 373 times)

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Drakman

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Davies Craig Thermatic fan Install
« on: March 24, 2019, 08:32:52 PM »
Hello Boys and Girls,

I am going to install a Davies Craig thermatic fan behind the radiator.  I have seen and heard of some of these installed before on Mokes and it seems that most people leave the std fan in place, why?  I am planing on removing the std fan and associated spacers, am i asking for trouble doing it this way?

I plan on cutting the fan shroud away on the front edge to allow air to flow through the radiator from the front through the grill.  If i set the thermo switch to come on at say 85 degrees it should keep the engine cool.  It runs at 76 degrees while moving but at idle while at traffic lights the temp creeps up to 90 degrees.

Has anyone had any experience with this sort of set up?

Cheers
Dave

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Re: Davies Craig Thermatic fan Install
« Reply #1 on: March 25, 2019, 12:01:31 AM »
G'day Dave,
I have gone down this path, sort off.
Have a Revotec unit fitted but kept the standard fan for now because I just cant fully trust it. I know that its a good system, but just cant let go, not yet.
I know that when I shut down, the fan still runs, its also set at 85 degrees. Maybe one day soon I'll remove the Standard fan and trust the electrikerie  :).

https://www.mokeforum.com.au/index.php?topic=13168.0

HP
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Drakman

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Re: Davies Craig Thermatic fan Install
« Reply #2 on: March 25, 2019, 09:28:13 AM »
H Tony, I have faith in the fan set up, in a previous life we were an agent for Davies Craig so i have installed a few on "normal" cars.

My concern is for the air flow through the front exiting out the side, once under way the air coming in through the front will be supplying the lions share of the cooling.  This is why i am going to cut the front side of the fan shroud away.  I have also made up a blanking plate that goes under the grill back to the sump to stop the air being pushed under the engine and away from the radiator.

I guess the old saying "suck it see" applies.

Dave

Terry

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Re: Davies Craig Thermatic fan Install
« Reply #3 on: March 25, 2019, 11:35:17 AM »
Hi,

rather than cut up your shroud, just remove it and replace it with some custom brackets to hold the radiator or mount your radiator to the body. If you are removing the original fan, the shroud serves no purpose other than for mounting purposes.

Your plans for a  'blanking plate' to the sump sounds like it could be blocking the air going past the fins on the gearbox which then means you could be looking at having to fit an oil cooler, but I can't picture exactly what you are doing from your description. You also want/need/should have air flowing over and around the engine as it provides more cooling than you might think.

Quote
I know that when I shut down, the fan still runs, its also set at 85 degrees.
Is there an automatic cut out on the fan or does it just run until the water temp is below 85 and where is the temp sensor?

Terry
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is.


Cujo. 1999 - 2016

Drakman

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Re: Davies Craig Thermatic fan Install
« Reply #4 on: March 25, 2019, 12:02:35 PM »
The blanking piece abuts the engine about  25 mm below the engine/ gearbox join so the sump still gets air flow over and around it.

Davies Craig fans use to come with the thermo switch included but these days it seems it be a separate part.  The thermo switch is adjustable between 40c and 110c it comes on at what ever selected temp is and goes off 5 degrees cooler.  You can over ride the thermo switch at any time though, we use to use an illuminated rocker switch, mounted somewhere on the dash, that  would glow green when ever the fan was running.

Hmm, mount the radiator to the body, now that sounds like a good idea, looks like a re design might be in order now.

Thanks Terry.

Terry

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Re: Davies Craig Thermatic fan Install
« Reply #5 on: March 25, 2019, 12:51:06 PM »
Davies Craig fans use to come with the thermo switch included but these days it seems it be a separate part.  The thermo switch is adjustable between 40c and 110c it comes on at what ever selected temp is and goes off 5 degrees cooler.  You can over ride the thermo switch at any time though, we use to use an illuminated rocker switch, mounted somewhere on the dash, that  would glow green when ever the fan was running.

I have dual DC fans set up on another vehicle pretty much the same as you describe here with the glowing override switch, however I was interested in HP's set up that suggest the fan keeps running after the ignition is switched off. I am thinking flat battery issues if the sensor is not in the radiator.

Terry
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is.


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Re: Davies Craig Thermatic fan Install
« Reply #6 on: March 25, 2019, 02:17:55 PM »
however I was interested in HP's set up that suggest the fan keeps running after the ignition is switched off. I am thinking flat battery issues if the sensor is not in the radiator.
Sorry Terry, worded a bit wrong  ::)
The Thermo fan is wired through the accessories. When I turn the ignition off and the engine shuts down, whilst the accessories is still on the fan will run until the sender ( thats in the top radiator hose) detects 5deg below the set point and then it will shut down, as in Dave's set up. When the ignition is completely off the fan shuts down with it all.

Hmm, mount the radiator to the body, now that sounds like a good idea, looks like a re design might be in order now.

It does sound like a good Idea, would look a bit odd without it, but cool.

HP
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FNQ

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Re: Davies Craig Thermatic fan Install
« Reply #7 on: March 25, 2019, 08:23:52 PM »
DRAKMAN


you obviously know these units and i have heard good things about the Davies Craig and recent spal fans - they pull big air


I have seen puller fans used in minis ( side radiator models) very reliably, but i have seen  a fuse blow including to the dash alert and fried a head ( didn't check temp gauge in a race as he was expecting the big red light to go on )- so not typical  - but it may be wise to ensure your alternator/battery can handle an additional 7 amps   -  most mokes i know could probably run all their accessories, plus lights plus wipers etc all on a 3 single amp fuse- okay a little exaggeration ,,,


and HP when you get the courage to detach the fan belt, tell everyone how many horses you unleash from the power unit.- my guesstimate - 2 hp- and unable to be felt by the seat of the pants-ometer

Drakman

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Re: Davies Craig Thermatic fan Install
« Reply #8 on: March 26, 2019, 06:50:55 AM »
Hi FNQ,

I do tend to keep a close eye on the gauges, I know what you mean about racing though, when that red mist gets in your eyes when the flag drops, nothing else matters, lol.  We race off road buggies and it's amazing the things you don't see during a race but when i look back at the Go Pro footage i think shite i should have backed off.

I have a feeling that this engine will run cool enough at speed but when it idles for a couple of minutes the temp starts to climb.  It is all a bit of an experiment, nothing ventured nothing gained.

The only thing that i remember as being noticeable with the thermo fan fitment was how much quieter the noise from the engine bay was.

Cheers
Dave


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Re: Davies Craig Thermatic fan Install
« Reply #9 on: March 26, 2019, 11:38:01 AM »
This was discussed recently on the Ausmini forum where a member asked about removing the bypass hose and thermostat when installing a Thermatic fan in the wheel well. I assume it wasn't you, Drakman?

The consensus was that the Mini (and Moke) setup is different to most other vehicles where the radiator is mounted behind the grille and hence subject to a strong cooling airflow when driving, so the original cooling system should be retained as is.

Here's some straight copy and pastes from that discussion.

I always thought the original fan remained in place so the electric fan only acted as a booster rather than a complete replacement. Instead of the electric motor running continuously it only comes on when the temperature reaches a certain level, perhaps in stop-start traffic or on a very hot day when the standard set-up can't cope. A well-maintained standard cooling arrangement should usually be adequate in most conditions.

Even on a coolish day, without a fan you will only get about 15km before the engine starts to overheat... and that's cruising at a fairly steady 80 kph - which are probably the most benign conditions the engine will run under... Maybe should have tried at 100 but I think the conditions would be worse...

I think radiator location is a major part of it.
With a frontal radiator, it sees 100% (for simplicity sake) of the airflow through the grill, after which the air exits below the engine, and through both wheel wells (let's say 1/3 each).
Mounting the radiator in the wheel wheel means it only gets 1/3 of the airflow coming through the grill.


« Last Edit: March 26, 2019, 11:39:39 AM by winabbey »

Drakman

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Re: Davies Craig Thermatic fan Install
« Reply #10 on: March 26, 2019, 01:23:51 PM »
Hi Winabbey, No not me on Ausmini.

I wouldn't remove the thermostat but i have deleted the by pass hose set up.

My original purpose for posting this was to find out what can be done safely with the thermo fan set up, as is stated in the mini forum east west engines with the radiator mounted in the side panel are a different beast from the "normal" front mount radiator.

My thoughts are that the thermo fan should be enough to cool the engine if the std engine mount fan was coping.  The thermo switch set to come on at say 80 degrees will enable the engine to reach operating temp quicker, when it reaches that temp the fan activates and , in theory, will cool the engine down to the set temp just as the engine fan would. 

The thermo fan will probable run longer than it would in a front mount radiator set up.  The std engine fan isn't doing much until the thermostat opens any way, as long as there is enough air to push / pull through the radiator it shouldn't matter whether the fan is engine driven or thematically controlled. 

I have installed a blanking plate under the front of the car to help move the air flow through the radiator and i think with the shroud and the engine fan removed/modified more air would pass through the radiator.

Please keep the ideas coming and let me know if or where i am going wrong with this, it's all a bit of an experiment.

Thanks
Dave

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Re: Davies Craig Thermatic fan Install
« Reply #11 on: March 27, 2019, 02:39:09 AM »
Hi,

there is also a difference in the way the air flows between a Moke and any other east/west set up(i.e. Mini) with the radiator exiting via the wheel arch.

The shape of the front panel allows more air to enter the wheel arch from the front when at speed and in some cases with a strong side wind can cause a situation where the air coming in is too much for the air coming through the radiator and you get a sort of blocked air occurrence that sends the temp upwards.

If you look at Vern's Moke(The white/blue/yellow/orange to the right of Dave G.)) in the page header of the Mokes lined up at Tamworth you can see can just make out he has an extra panel fitted by the previous owner on the front left to reduce this flow of air from blocking the flow. On a normal day it can drop the running temprature around 3 degrees and on a hot day 5 degrees and stop the issue i described with the side wind from shutting things down.

Terry
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is.


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Re: Davies Craig Thermatic fan Install
« Reply #12 on: March 27, 2019, 06:09:46 AM »
Hi Terry,  Yes I remember seeing the moke with the extra section on the front at Moke fest, so that stops the wind effect coming in from the side.

 I am aware  that i could get problems because of the east west layout and air flow.  I did notice it runs cooler without the grill and  number plate removed, looks a bit crappy like that though. 

Dave