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MG MGA - Electric Fan

I have acquired a Kenlowe elecric fan which was mounted with plasic tags pulled through the radiator core fins. I intend to fit this fan on my A but am reluctant to tag it to the rad. core fins as I don't want to damage the fins. Any other more logic way to fit it? I do not have any other mounting fittings for the fan.

Frank
F Camilleri

Frank,

yes platic tags through the rad unsettled me too.

I bought the optional mounting kit, which I thought looked naff so I didn't fit it.

I ended up mounting the fan by drilling two holes in the radiator duct panel which matched two slots on the bottom of the fan. To stabilise it I made an aluminium plate up that bolted to the top of the an and then to the bolts where the bonnet catch goes. Nice and solid. It's not the best work of art, but I plan to tidy it up.

I am away from home for a few days, but I'll post a couple of pictures when I get back.

Good luck,

Grant :-)

G Hudson


Frank,

check www.spal.it , they have a nice fitting kit. Hopefully it will fit the Kenlowe fan...

Siggi
Siggi

Thanks Grant, yes I would love to see your set up, please post some pics as soon as you can,
Siggi thanks for the site, I will check it out right now.

Frank
F Camilleri

Frank
Look up Neil Ferguson's thread (02/November/2009) named :twin radiator fans: (the Davies Craig type).

You will see that they were fixed to the radiator by plastic threaded rods that go through the radiator core near the top and the bottom where there are no fins on the tubes. The outer fixings used extra bolts through the radiator fixing flanges.

I would imagine that they will supply parts of their fan fixing kit that you could use to fit your kenlowe.

Or the pictures on Neils thread may help you to design your own.

Colyn "Tripods"
Colyn Firth

Thank you so much Colyn. Will have a look.

Rgds
Frank
F Camilleri

I've managed to install the Kenlowe fan which I attached to the front of the rad. Since the car is positive earth, I had to reverse the connecting wires to get the fan to turn in its normal direction, i.e., clockwise. It is now pulling air from outside the front grill into the radiator. I don't have any instructions with the fan but I am assuming this is the way it should be fitted to have the desired effect. Does reversing the fan's polarity have any ill-effects on its motor?

Frank
F Camilleri


Frank,

if your blower is pulling air it must be mounted behind the radiator, i.e. engine side.

Siggi
Siggi

I think he meant pulling air through the grille and pushing air through the radiator. Lots of aftermarket fan motors can reverse direction of rotation simply by switching the wires. If you also turn the blade around (for best efficiency) it can then be used as either a pusher or puller.
Barney Gaylord

Barney

I understand that what you were trying to say was that if you change fan rotation direction by swapping leads etc you may also need to turn the blades round to keep the correct blade profile facing the airflow. What the unwary should understand is that merely turning the blades round but keeping the direction of rotation the same does not change a puller into a pusher or vice versa. The air flow past the fan blades will remain the same; just the fan efficiency may be altered, depending on the blade aerodynamic profile.

Steve
Steve Gyles

Well, no. I just stated the short version. If you turn the whole unit around to change from pusher to puller, it rotates the wrong direction. Then you switch leads to rotate the right way, but the blade is backward. Then you pull the blade off and flip it over to have correct blade profile for best efficiency. You can use it for either pusher or puller, but you have to set it up with the correct combination of motor orientation, motor rotation, and blade orientation.
Barney Gaylord

My fan came off a Tiumph Tr3a and it was mounted in front of the rad, with its blue wire connected to supply and the black wire to earth. (The Tr is converted neg- earth). This way it was rotating clockwise, looking at it from the front of the car, with the blades pulling air from outside the front grille and through the rad matrix. Mounting it on my MGA (being Pos+ earth), when I connected the wires, blue to supply and black to earth, the blades rotated anti-clockwise with no effect at all. I reversed the wires, (black to supply and blue to to earth), the blades were now turning clockwise, their normal direction of rotation as indicated by an arrow on top of its plastic frame. Am I right in saying that if the fan was mounted behind the fan as Siggi suggested, it will be pulling HOT AIR from the engine and blowing it through the radiator. Surely this would heat the coolant in the rad much more rapidly than normal thus negating the cooling effect of the rad. I always thought that pulling COLD AIR from outside and onto the rad will keep the liquid fairly cool to circulate inside the engine thus preventing it from overheating. Thank you for all your inputs and any further comments on this subject are always welcome.

Frank
F Camilleri

Frank said: "Surely this would heat the coolant in the rad much more rapidly than normal thus negating the cooling effect of the rad. "

Not really, the radiator will still cool but not any where near efficiently. This will overheat the marginal MGA system. As long as the air temp in the engine compartment is lower than the coolant temp (~190 deg) the radiator will lower the coolant temp, albeit, minimally. Do not do this. Maybe this is what you meant.

Regardless of whether the fan is in front of or behind the radiator, if the fan is turning in the direction it was designed for as indicated by the arrow, and the air flow is from the front of the radiator to the rear, then all is well. You have the wiring correct with black to supply and blue to to earth. BTW, from my understanding, only some Kenlowe fans have reversible fan blades. It is model and size dependent.
Chuck Schaefer

Frank

See my schematic. Placing the fan in front or behind the radiator will draw air through from the front of the car, provided the fan is still orientated the same way round. It is only if you turn the fan around when relocating behind the radiator would the air be pushed forward (image 3). This all assumes that the wiring remains the same. In the third image you would then have to swap the wiring over again for the fan to suck air from the front (reversing fan rotation direction).

Steve

Steve Gyles

Modified schematic attached.

Steve

Steve Gyles

Steve, the fan I have, which is a Kenlowe fan, can only be mounted one of two ways. One way is attach it to the front of the rad with clockwise rotation of the blades. The other way is to attach it to the rear of the rad, again with the blades turning clockwise. Either way the fan will act as a puller. The only difference is that being mounted on the front it pulls cold ambient air and pushes it through the rad fins, while if mounted on the rear it pulls heat from the engine and pushes it through the rad fins. Looking at it logically, pulling cold air from outside and onto the rad will have a cooling effect on the rad coolant, whilst pulling engine heat onto the rad matrix will keep the coolant constantly hot. It is important to note that the fan blades cannot be turned around. The fan frame is not constructed for this. Secondly, for the fan to be effective its blades have to be turning in a clockwise direction only. If the wires are reversed its direction of rotation is also reversed but the blades will be non-effective.

Frank
F Camilleri

some comments....
It is more efficient to have the fan on the engine side ( provided of course that it pulls cool air from the car front through the radiator)
I looked at large number of fans and could not find one that could be put in above position without changing the pulley arrangement. I did not want to do this as it is wise to keep the belt driven fan in the boot.
Mounting the fan on the front of the raiator is the practical way to go provided you mount it directly on the face of the radiator so the air has to pass through the radiatorand no just circulate around the fan ( I have seen this dorkish arrangement on other cars....not MGAs of course ).
Neil Ferguson

Hi Frank,

sorry for the delay. Here's the pics of my fan installation. It's only the first version and is a bit rough and ready, but I think yo should get the idea.

Cheers,

Grant :-)

G Hudson

Hi Frank,

here's the base.

cheers,

Grant :-)

G Hudson

I would like to add a further complication.
On DC electric motors reversing the positive and negative leads only reverses the fan direction if the field magnets are not coil wound.
If the field magnets are coil wound the current is reversed in the field coils as well as the armature and the motor will still turn in the same direction.
Is this correct?

Mick
M F Anderson

Grant....I have to say that the arrangement you show looks excellent from the support/structural perpective but less than ideal from the cooling air movement perspective...reasons....
These fans are basically very simple high vol and ultra low DeltaP compressors and their 'characteristics' mean that they will seek the least resistance to airflow . This in turn means that if you leave a gap between the radiator front face and the fan exit much of the air will recycle from the exit to the entrance of the fan....you seem to have such a gap.
Some air will go through the radiator but nowhere as much as if you bridged the gap with a seal of some type and forced the fan to operate at a different point on its 'characteristic' curve of airvol v DeltaP.

Neil Ferguson

Neil,

thanks! Well spotted - the gap is one of the "tweaks" I'm working on, as I realised after fitting it that the fan should butt up to the rad.

cheers,

Grant :-)
G Hudson

Grant..I think if you used a strip of sealing material ( such as the windscreen sealing rubber .. thick type..US Moss Part type 280-735....or similar..it comes in about 2inch wide strips and I have used often for jobs on the car ) and fixed it around circumference of the fan inside ( if room around fan blades) or most likely outside and had it just touching the radiator front to form an extended shroud you would have close to perfection ( and that is a difficult state to reach!).
I know after I fitted my fans close to radiator front and turned on in the garage there was a veritable gale through to the the engine bay. Great stuff!!!
Neil
Neil Ferguson

Grant, your set up looks fine to me, looks very neat. But as Neal pointed out with a gap between fan and rad the effeciency of the fan is greatly reduced. I have attached my fan temporarily using plastic tie belts and tied it to the top tank, one on either side, and one round the bottom tank. The diameter of the fan frame is too large to fit flush against the rad matrix, and therefore I too ended up with a inch or so gap between fan and rad. As I said this is only a temporary set-up. I am only trying a fan which came off a TR3A. I will remove it again and fix a rubber strip around the circular part of the frame, and this would close the gap nicely. My intention is that if this fan is effective, and I will notice an improvement in engine temperature (i.e., engine running cooler), I will fit a slightly smaller fan that would mount flush to the rad. I like your pre-fabricated bracket, is that ss or aluminium? Looking at you second pic, I cannot figure out how you attached the fan at the base. Or am I to assume that there is no fixing there?


F Camilleri

Guys.....I reported some time ago on a thread that I fitted two smaller diameter fans to mine before last Oz summer to get good face coverage on the radiator and it has been working very well here in Oz. I had to scout around for fans that would fit flush on radiator but final assembley..attch pics..one inside car and other of assembley ( need to take radiator out to do a neat job )

Neil Ferguson

..and other pic.

Neil Ferguson

Neal, that's a brilliant set up you have there. I may also opt for twin fans. If I may ask, what is the external diameter of the fans you used? I would presume that both fans pull cold outside air through the grille.

Frank
F Camilleri

Frank....see Barneys site CO-111 as follows..
http://www.mgaguru.com/mgtech/cooling/cool_111.htm.
h
He has all the details of the fans and the set up for the dual (inch fans...
neil
Neil Ferguson

Frank..message was supposed to read ' dual 9 inch fans'....and in answer to your other query the fans pull cool air from the grille and push very very strongly through the radiator independent of road speed . When they click in (on the thermostat control) the coolant temp reduces very rapidly ...
Good luck
Neil
Neil Ferguson

Thanks Neal, I read through CO-111 on Barney's site. Extremely well detailed and very easy to understand. I saved a copy on my documents files for future reference.

Frank
F Camilleri

This thread was discussed between 27/07/2010 and 10/08/2010

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