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MG MGA - Twin Radiator Fans

Further to a recent thread I have just finished fitting two Davies Craig 9in fans and a single Davies Craig control system and attach a pic of the arrangement.The fans fit fairly neatly under the radiator top reservoir ledge ( wiring to be improved !) and controls fit under the heater air inlet duct at top of pic.
At bottom of pic you can see the Tudor plastic atmos overflow bottle ..its cradle is connected to a small bracket bolted to the radiator mounting flange.This may block a little air .but it would be hot air to the carbs ..so not too concerned.
Set the control to kick in at about 193degC ( water thermo is 180degC sliding sleeve type) and went for a hilly drive. All was very stable ..fan cuts in and cools the water down about 3degC and then cuts out after about 45sec..as per spec..Water flowed in and out of bottle. Now need a really hot day!!
...also decided to stop using antifreeze ( this is Austalia !)and using Castrol Corrosion Inhibitor with demineralised water. Any one with experience or advice ??


neil ferguson

Neil, Is the thermostst bulb under the top hose? That is where I placed mine and got an earlier switch on response when I moved it to the head end. That is where the water is at its hottest, as it leaves the motor. I was amazed at the difference in temp in such a short distance. The fan now switches on very early, but only runs for a short time. On long runs (on "hot" days) it almost never runs, but stop in traffic, and it runs and runs!!
Maybe I need two fans.
Barry
BM Gannon

Barry..the element is fitted as per the Davies Craig leaflet--ie under the hose at the radiator end. I suppose one problem could result if the radiator loses water ( expansion ) and this hose could run part full.

neil ferguson

My error ...read degF for degC in my initial posting...
neil ferguson

I am not nearly this far along in my project yet - but I was intrigued by the photo of the two side by side fans. Davis Craig is in Australia, but is there a US supplier for similar items? I found lots of listings for fans, but few 9" ones. Is there a Mustang or VW part that would fit our cars? I have an original radiator which appears to be in good shape, but I have never tried it.

JIM
AJ Mail

I have had overheating issues with both of my MGA's in the thirty-odd years that I have owned each of them. In 1996 we entered our 1600 roadster at Silverstone and found that most of the UK cars were running electric fans! I remember saying to the owners "spare a thought for us in Oz where temperatures can get over 40!" I find that getting the radiators rodded out overcomes the problem for at least three years and have not succumbed to the fan mod. The radiators are not difficult to remove/replace (especially after you have had some practice such as I have had!).
Barry Bahnisch

AJM...whilst looking for fans on the net I did come across other companies that sold 9inch ..some in US..try googling. I chose Davies Craig as they are close here in Oz and have good support service as well...but they are far from unique. The important issue is the max OD of the fans as they needs to fit snug to the radiator and above the metal apron below.a distance of only 26.5cm on my car ( 10.43 inch ..be sure to measure you own... MGAs were made in the time of 'fitters' and without any real tolerancing )..only a 9in fan can do this...the width is important but if you make the height the width seems to make it and you can have a very slight overap each side...and it helps to secure the unit to the radiator flange.
It is an impossible job in situ and you need to take the radiator out and fiddle with location and orientation and marking etc...to get all the supports in position.
I attach a pic I posted earlier ..if you want more detail ... just ask...
I have been out a few time amd the fans and the controls are working very well. Waiting on a tarmac melter day now ....
Neil


neil ferguson

That looks like a very neat job!

JIM
AJ Mail

An Update for those who live in a civilised climate...
I wrote the original note about the installation of two 9 in fans in Nov last year and have operated through the Oz summer with the system and with no reliability or temp problems . The ambient temp max over this summer in Southern NSW was a relatively low 32oC ( 90oF ) so no real extremes but the reaction of the system leads me to believe it will cope with all expected conditions. Traffic crawls created no problems.
Another comment would be that I had to remove the radiator during my recent work installing the 5 speed box and the radiator came out and went back in fine with the two fans in place on its face...and hook up of the controls went without hitch.
Very pleased with the kit!
Neil Ferguson

Neil, nice fan installation.
Does having the two fans in front of the rad increase the running temperature when you are on the move compared to before they were fitted? They do look like they may mask the rad a little and I wondered if you had noticed any temp increase whilst driving?

I quite like the idea of fitting an electric fan setup to my car which over here in the UK runs at 175 degrees F with the standard metal fan. I was wondering whether an electric fan on its own would control the water temperature if I fitted one and removed the standard fan.

I have also been looking into fitting a viscous coupled fan or the Flex-a-lite? mechanical type from the USA to control the temp when in traffic but reduce fan noise and avoid power wastage due to the fan at higher revs.

Very interested to know what you think.

Colyn
Colyn Firth

Colyn...
I have not noticed any loss of cooling due to the fans acting as a partial shroud. There must be some as the fans have a cross section which must reduce airflow when they are not working but it does not seem appreciable. My belief is that this is not a significant factor either as the main issue is how much air is moved though the radiator and over how much of the face area when the fans are on and whether this can cope with peak temp conditions. The two fans I have are only on for very brief periods and the blast through the radiator is tremendous ..when driving I can see the temp build up to about 195oF on the gauge and then reduce rapidly by about 7 of 8 degrees before cutting out.I certainly don't need the belt driven fan ( though I kept it in the boot for a few months!)
I considered the most important factor when choosing the fans and fitting them was to get the fans as close coupled to the front of the radiator as possible so the air was truly forced through the radiator and not recycled ( I have seen set ups in other cars that just did that...useless! ). The 9in fans came with rubber seals around the trailing edges of their cowls and I left these in place and they are up hard up against the face of the radiator so they ensure all the air goes through..and also protect the radiator fins from damage..
I have great doubts about whether a single 9in fan without the belt fan would cut the mustard, even in Yorkshire....the reduced airflow and the small area of radiator affected would grossly hinder cooling and larger fans would need to be set away from the face.
One bonus from the electric set up ..there seems to just a wee bit more umph from the car...not much.. but noticeable.
The idea of a vicous coupling sounds good..presume this means the fan would just feather when not needed...I am not familiar with Flex-a -lite you mention but any device that would limit the energy take of the fan to when it is needed ( ie at operating temp ) is a benefit.
Neil Ferguson

Colyn...one more point..
I looked at a huge no of fans to see if I could fit a puller..but without changing out the fan pulley for a bastard could not find one to fit.
A puller would have been best cooling arrangement.
Neil Ferguson

Thanks for that Neil,
it looks as if your twin fan set up is going on to my "To Do List".

On your installation how are the fans fixed together at the centre of the rad and also do you have to secure them through the rad matrix somehow to hold them tightly to it?

I can visualise the fans bouncing about a little in the centre if they are not secured to the rad there.

Another advantage to your set up is that you will be able to access the generator fixing bolts, fan belt adjusting bolts and fan belt much more easily with the standard fan removed.

Thanks again

Colyn
Colyn Firth

Colyn..
it is at times like this that you realise you should have taken more photos...but I can explain how the fans were mounted and have also attached another pic of the assembley.. I posted one earlier as well )before it was put in the car.
Points..
1)The fans were placed hard up against the underside of the top reservoir of the radiator ( need to do this to get the required assembley max height of 26,5cm ( 10.43in ) as per my car.The fans were almost flush with the radiator front and looked very neat.Check your own distances as you may need to trim a wee bit of plastic off the fixings..see 6) below
2)The outside edges of the fan housing ( but not the fans) overlap the edges of the radiator.In particular two of the fixing holes protrude beyond the radiator edge. This is very useful..see 4 below.
3) I bought additional metal mounting kits ( options ) with the two fans and this came with metal threaded screws ,nuts etc and cushion pads. Standard kits supplied with the fans have a nyloc type rods with push on end fixings.
4)On each side of the radiator I marked out two holes for the metal rods (referred to in 3 above) to penetrate the flanges of the radiator and drilled such. You can see these rods in place on one of above photos.
5)Two fan fixing holes were close to the underside of the radiator top reservoir and at the location there are no horizontal fins and good clear gaps to fit the rods through without real contact. I fitted two metal rods at the top of each fan and made sure they were very well cushioned/load spread on the other side of the radiator.
6) For the two lower fixings on each fan I used the plastic rods referenced in 3) above and threaded them very carefully through the radiator..again cushioning them on other side. You can see the ridged heads of these four rods in the front of the photo and I had to cut a few mm off the heads to make the 26.5 cm distance.
7)I worked very much on the principle that I wanted no risk of relative movement of the fans to radiator so all up each fan is secured with 6 rods ( 4 metal and two plastic ).
8) Since 4 small metal screw heads are now on the back of the radiator mounting flanges I inserted a double thickness of hard rubber gasket with cutouts between the radiator and car flanges.I used glazing rubber ( moss part 280-735 ). The thick hard one not the soft squidgy type ( I mistakenly bought the hard one some time ago so Iam 'long' in this rubber strip). It is about 2mm thick..but nothing magical here ..any thing that will bridge the gap!. Moving the radiator forward this small distance gave no problems ( on my car!)
9)One point..I mentioned that the back of the fans were suppled with rubber seals and this was not so...I found some edging rubber in my garage and fitted it on the back of the fan shrouds where they butt up against the radiator ..not sure it was necessary but as an engineer I had always adopted the principle of belts, braces and a nail through the navel to hold trousers up!!..and old habits die slowly.
Hope above helps.




Neil Ferguson

It should also be noted that a further advantage of an electric fan (especially useful in colder climates) is that the engine reaches operating temperature that bit quicker.
Neil McGurk

Colyn...
adding another pic of the fans in the overall engine compartment.All looks reasonably logical ( but not pure!!). Taking the mechanical fan out generates a load of space behind the radiator.
I also took the opportunity when I recently put the 5 speed in to relocate/recess the air inlet hose to the side of the compartment and complete the bulkhead insulation ....with the ambient air through the heater box fitted with fan ( heater hoses not hooked up ) and the insulation plus extra insulation inside the cockpit (when i recently recarpeted) all is now very cool and comfortable.
I also recollect a recent thread about venting the tappet cover ..my alloy cover( a recent installation ) came without a breather hole and you can see I drilled, tapped a hole and connected it via the existing hose to the air intake filter ( K& N with internal small horns ).
I think it is the small horn , the removal of the fan, plus the pleasure, precision and range of the 5 speed that is giving me the combined feeling of a wee bit of extra umph.I can put the power were I want it.
Next step is to go over all the spark electrics ,timing and carbs to see if I can get the tune much better as the exhaust smells rich and I just connected everything after the box installation ( bought myself one of those flame watchers (gunston? as well ) ...
The two fused relays I installed when I put in a flash dipper and other switches on the dash can be seen on the very front next to the bonnet closing mechanism.
...and still no oil drips..first time in 20 years since I bought the beastie!!
Neil


Neil Ferguson

Neil,

What type of SU's are they?
The short tapered neck on the piston cover looks like a HS8, but the HS8 has four mounting bolts to the manifold, yours have two bolts.

Mick
M F Anderson

Mick..they are standard SU H4 carbs fitted with a tarty bright cover which changes to profile slightly...
Neil
Neil Ferguson

A brass bung was soldered into the base of the radiator in my 58 roadster. To place a capillary tube sensor under a radiator hose seemed too cobbled on for my tastes. In the bung I placed the fan switch from an early Honda. Honda Subaru and Nissan all used switches that share the same thread size. There are many different temperatures avalable. I also can turn on the fans with the "F" light switch. The fans I used are larger than 9". One is front left and the other on the back right of the radiator. One pulls and the other pushes the air. The car has no mechanical fan.
R J Brown

Thanks Neil
I like the look of your installation more every time I look at it, I would think that if it can keep your car cool in Oz, it should cope with temperatures over here very easily.
I have looked into obtaining Davies Craig fans in the UK and they are definitely available here so they are going to be my next project on the car.
Thanks again
Colyn
Colyn Firth

Hi Neil.

A nice look with the thermal insulation- would you mind sharing the source/brand etc? And did you use same inside the cockpit , under the carpet?

Mark Thompson
M THOMPSON

R.J.Brown..agree with your general sentiments. I like a fit for purpose job and the element under the hose seemed a wee bit Heath Robinson. I did buy a kit which included a short insert to go in a hose and then insertion through a side entry in the insert..but there is nowhere to put it in the hoses on the mga. I don't have an extra tapping in my radiator so that was out. I have had this element in the hose for getting on 6 months and had no issues ..I even had to pull the whole thing apart two times when I removed the radiator once because of an error and the second time for the 5 speed installation. The capillary connecting tube where the clamp is situated sits in a groove in a special neoprene sleeve and I wrapped extra tape around. So pragamatic inelegance seems to work and the system allows me to adjust the temp of operation easily.

Mark..I did the lazy thing and ordered Moss US parts via LBC..inside the engine bay I used Hoodliner part 409-05 and under the carpets and over the transmission tunnel Heatshield 409-015. The former is a ridiculous price and I am sure you can get equivalent in Oz at a fraction. I followed some advice from someone on this site and used the carpet pieces as templates and glued the undercarpet to the carpets ..it made the latter stiffer , neater and easier job.
I too like the clean bright look of the heatshield in the engine bay and it covered up a galaxy of star light holes in the bulkhead..a lot more comfortable now. Do you have a heater/ventilator in yours?
Neil Ferguson

Any competent radiator shop can install a threaded bung in the bottom housing of the radiator. See picture. I used 2 11" fans.


R J Brown

RJ, do your two 11" fans overlap the outer edges of the radiator by very much and also at what temperature does your thermostatic switch the fan on? I assume that the bottom of the rad runs cooler than the top.
thanks
Colyn
Colyn Firth

This thread was discussed between 02/11/2009 and 03/05/2010

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