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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - electric fan

Happy New Year to you all.
It is about time I thought about a little more ecconomy and replaced my engine driven fan with an electric one. In the past (20 years ago) I used a Kenlow one but was not impressed with its power and so got one off of a Fiesta from the breakers yard which was much better. Now Kenlow fans have improved and there are others on the market too. What do you guys recommended?
D Brown

I use Vauxhall Cav circa 1993.

Power isn't normally a problem... it's how well/effectively the fan blows through the rad...

A
Anthony Cutler

I've got the Revotec cooling fan kit (£50+ more than the Kenlowe cooling fan kit)

I'm not sure the Revotec fan is quite big enough but it does the job

I do like the thermo-switch that fits inside the top hose (instead of the Kenlowe 'probe' that is pushed inside passed the jubilee clip)

You can buy the Revotec thermo-switch sepertately and add a Kenlowe fan unit I understand
Nigel Atkins

I use a Rover 400 unit, controlled by a thermostat on the top hose. It rarely comes on, but then I am rarely stationery for long when driving! Sometime I mean to add an override switch so I can also switch it on demand although the thermostat seems to work well enough.

Guy
Guy Oneandahalf Sprites

I also use the one from a Rover 400 I think. I have a switch mounted in my Peugoet Rad and also have the override facility. Naturally only comes on if stuck in traffic.
Bob Turbo Midget England

Guy, I've never seen the need for an overide switch in any of my cars if the thermo-switch is the correct one and working

Rather than bothering to fit an overide switch why not just set the existing thermo-switch to come on sooner but as you say it rarely comes on now and it seems to work well you probably need neither

Mine is wired to remain on or even turn on after the ignition is turned off I've had absolutely no trouble with draining the battery ( I do have an uprated alternator and starter motor fitted tho')
Nigel Atkins

Point taken Nige, I supppose I have an override fitted simply for peace of mind!! sometimes I just like to switch it on when the ambient temp is up above 30 and approaching major traffic (sadly temps generally in Europe!)

I also have mine on the non ignition side so that when temp rises on stopping fan operates for a short while.
Bob Turbo Midget England

Does the rover 400 fan suck or blow?
Dave
D Brown

Mine is a sucker so I assume if the Rover one is a blower then I got mine off a different heap of scrap! :)
Bob Turbo Midget England

Nigel, you are probably right about not needing the overide. It has worked without for about 8 years so far. Just thought it was something l should do !
Doesn't any fan suck from one side and blow from the other ? I don't understand how else it could be.
Guy Oneandahalf Sprites

You say you weren't impressed with the Kenlowe fan in respect of it lack of power.

What size was this Kenlowe and was it new or secondhand. It wouldn't be the fault of the Kenlowe if the one you tried was simply too small for the cooling requirement you placed on it.

I had a s/h Kenlowe that I used on my Sprite for something like 20 years and it was still working ok when I removed for a new and slightly lighter Kenlowe. It was probably the best value s/h part I ever purchased.
Daniel Thirteen-Twelve

I'm not over impressed with the Revotec fan unit I have fitted but it does do the job just it seems to take a little long than I would like, doesn't quite move enough air or quick enough for me - but it does do the job

I can assure you fan are push or pull (blow or suck, behind or in front of the rad) as the Revotec one I fitted was the wrong type - of course I didn't find this out until after I'd completely fitted it (I did test it to see if it worked before I fitted it to check it worked fully but not the direction of flow, a mistake I will never make again

Initially Revotec told me I was wrong as they are very careful when packing the kits, I had to read the model number from a very small label fitted upside down thro' the rad grille before they admitted that yes infact I had the wrong fan unit

To be fair they got the correct unit to me for the next day but failed to collect the incorrect unit the day after

To fit the fan unit out comes the 4-LIFE again and rad, cowling and grille but at least this time I knew all the nuts, bolts and washers were fitted, new and easier to get at

I also found when the Revotec thermo-switch was fitted to ignition side I had engine run on (might not have been the cause tho') but the Revotec designer I eventually meet at the NEC was unable to help me with an answer
Nigel Atkins

As noted Guy fans are designed to suck and some to blow.

Generally when getting one from the scrap yard simply note which side of the radiator the original is fitted.

If it is fitted in front of the rad then it is a blower, if it is behind the rad it is considered a sucker.

However the vast majority of rad fans will reverse themselves if you reverse the polarity unfortunately whilst this will rectify the air flow direction it is generally accepted that the fan operating in the wrong rotational direction will be less efficient than when rotating in the direction it was designed.

Rule of thumb should be get a fan that sits in the same orientation as what you require (in front or behind the rad)

After fitting ALWAYS run the fan and ensure the air is flowing through the rad in the same direction as the travelling forward airflow.

I have seen a number of electric fans that were fitted the wrong way thus blowing air through the radiator opposing the natural flow of air when travelling forward. This will result in overheating when the vehicle is moving forward and the fan is energised.
Robert (Bob) Midget Turbo

Following on, fan blades are usually designed with a curve - that is, the leading edge knifes directly into the air, and the trailing edge then curves to a steeper pitch to push the air.

In other words, the intake side of the fan will present the convex surface of the blades to incoming air. And as Bob stated, a blade that pushes air with the convex side is far less efficient than one that's (correctly) scooping and pushing air with the concave side.

Hope that makes sense. And apologies if I'm stating the obvious!

;-)

-:G:-
Gryf Ketcherside

OK, in those terms I understand that there is a difference between a suck and a blow fan. It relates to whether the fan is designed to be positioned in front or behind the radiator.

I was reading it too literally. Clearly the flow of air sucked into the fan must match the discharge of air from the other side. Where else would any difference in the volume of air go? So every fan must both suck and blow.

That isn't of course the same as saying the fan is designed to work most efficiently in one or the other location in relation to the rad. On the Rover 400 that mine came from it is mounted in front of the rad, which is where mine is fitted on the Sprite.
Guy Oneandahalf Sprites

Spot on Guy
Mine is therefore not from a Rover 400 as mine is a sucker and is mounted at the back of the radiator
Robert (Bob) Midget Turbo

My MGB fan sits in front of the radiator

It's said here often that this will "encourage" overheating because of having a big dollop of a motor in front of the rad will impede airflow through it

I would have thought that as the air bunches around the motor it speeds up and then returns to normal after it shouldnt matter

I cannot say I have ever noticed any sign of it running too hot because of this, although my engine did get very/quite/rather hot when in some of the traffic queues in "that London" on Sunday

But this was because, when I rewired the fuse box on the car with two six ways blade fuse holders I fitted a 10 amp fuse which had blown. The car now has a 15 amp fuse and the MGB fan works happily again

(For those behind me that reported a brake light failure...Blimmin' "Ring" Relay had failed. Sorry, new one fitted this afternoon but now looking for a better Bosch one to fit)

I have the fan switch fitted to the spare boss on my upright early type radiator, running off a relay and also have an override switch on the dash

Well I never used the optional instrument lampswitch for that anyway
Bill 1

From my experience always test which way the fan puts the air before fitting

As I’m very not technical I checked which way the fan should “point” by taking the front off the bathroom extractor fan (well it needed cleaning anyway and it confirmed that Revotec had sent the wrong fan before I rang them and made a fool of myself)

You can also use the smoke test, of course when I wanted to it was too windy and the rad is set well back from the grille – I don’t smoke so matches and card had to be found

And being non-technical I understand what Guy means by all fans must suck and blow so perhaps looking at them as pulling or pushing might help (altho’ I’d also see that you might also say that all fans must also push and pull but imagine that if you are pulling something or pushing it)
Nigel Atkins

Daniel,
I was not impressed with the kenlow. But thinking about it, it did end up on my 104 BHP Oselli built 1400. I replaced it with one from a mk2 fiesta which worked a treat. I think the one to use nowadays seems to be one from the Rover 400 - about £20 on ebay.

Guy, Bob,
How did you fit yours to the rad?

Thanks
Dave
D Brown

Mine is fitted with a spare from a MG metro, as it is pretty much
same A series engine it does the job well.
P C Knightley

Dave,
On mine I took the complete fan, motor and the shroud unit from the Rover 400. I then trimmed plastic shroud down a bit so that it fitted in in front of the radiator, bolted to clips that I made that attach it to the original Spridget radiator supports. The shroud covers the radiator so that the no air from the fan can spill out to the sides.

Guy
Guy Oneandahalf Sprites

One of my Winter jobs is to replace the existing electric fan with a spare Kenlowe that I have. The existing set-up came with the car when I bought it and is quite frankly useless. I understand that it came from an Allegro. Nothing wrong with that, but it's mounted a good six inches away from the front of the radiator with no cowling or ducting as far as I can make out.

There is an override switch already wired-in that I shall keep in the belief that some airflow through the engine compartment when stationary might help to keep the under bonnet temperatures down and help with fuel evaporation problems. (bigger problem with a 1500 than the cooling system)

I saw 4-Life radiator coolant mentioned here - anyone got any opinions on it?

Dave
D MATTHEWS

I've used 4-LIFE on many vehicles over many years

It's in my mate's (20 year old?) Toyota from new - 4-LIFE is labelled as 10 year life

I found out very recently that it's not necessarily recommended for engines that are not new or fairly recently reconditioned

The main benefit I've found is that it's excellent in identifying the source of small leaks

You use it UNDILUTED so also avoid the problems with using a tap water mix of engine coolant

As 4-LIFE is for 10 years before using it you want to thoroughly flush, back flush and flush again, then clean and then flush and back flush and flush yet again the rad, heater matrix and if posible engine block (certainly empty, flush and clean engine block)

Also replace as required water pump, and certainly the hoses (fit & forget classic silicone hoses - http://www.classicsiliconehoses.com/ and rolled edged jubilee clips)
Nigel Atkins

Nigel,
Other than its longevity, are there any other benefits?

Given my habit of tinkering with the engine, and fairly frequent draining of the system, long life could be a disadvantage. If I drain my system in the summer for any reason, I just refill with plain water (soft water area, here)and only bother with an additive when preparing the car for winter.
Guy Oneandahalf Sprites

Thanks Guy,
So I will fit a Rover 400 fan to the front of the rad.
How about the controller? Kenlow or Revotech? Or are there others available?
I have put 4 life in mine last autumn but I too am a little concerned that I will tinker and drain some of it and it will end up getting expensive.
So far it has done what it should. It keeps the engine cool quite well, so well infact that I have had to put in a hotter thermostat to make the heater work.

Dave
D Brown

I usually end up draining my system very shortly after putting it in for various reasons

Before my current midget I usually changed my cars on average every 12 months so I certainly didn't use it for economic reasons in the short term

I usually replace with the 4-LIFE with new but a couple of times as it was so recent on my Midget I've reused it

If it comes out clean (not easy on mine as I have to empty from the bottom hose) into a clean container I don't see any reason why it shouldn't be reused (I put it thro' some sort of filtering if I'm to reuse it)

Don't under estimate the importance of it being useful to find leaks - on a V8 b I had it looked like the rad had a small leak on the rear but on studying the spray pattern more closely (and this was before CSI) I saw it was actually from the water pump (a common thing with the Rover V8)

Also it's helped me find very small leaks with clips ect.

other advantages are on here - http://www.mgocaccessories.co.uk/acatalog/MGF_COOLING_HEATING.html

or here - http://www.holden.co.uk/displayproduct.asp?pCode=080.861

Had another mate had it in his P5B it almost certainly would have persuaded him that he had head gasket failure a lot sooner than I could convince him (he knew really but was in denial)

In answer to Dave - Revotec thermo-switch
Nigel Atkins

Dave,
I cut the top hose between the thermostat housing and the rad and put in a plastic fitting(available from Burton Power) which takes a standard thermostatic switch. This controlls the fan itself via a relay which is fused. I also have a warning light on the dash so I know when the fan is running.

The screw-in thermostatic switch came off a scrap-yard Fiesta but they are available anywhere. It isn't adjustable, but you can buy them for a range of temperatures. I think mine is 104 degrees C, but may be a 97C. I know it doesn't come on very often, but when it does it drops the gauge pretty quickly. It does sometimes come on after I switch off the engine. With the front mounted fan this isn't a hazard if I immediately open the bonnet, which I suppose it might otherwise be.
Guy Oneandahalf Sprites

I have a pic of my thermostatic switch, which sounds like the same housing as Guy's, in this set.....
http://www.eatworms.org.uk/mg-midget/projects/78-midget-dashboard

97 on and 92 off which in practice feels a little high. I do have an overc ride switch and like Bob stick it on before hitng traffic in high summer temps. Very useful in the traffic around Le Mans especially.
Dean Smith ('73 RWA)

I recently replaced my Hayden 3670 10” electric fan (which Moss recommends for spridgets) with a Spal 30100411 11” ‘slim fan.’ It’s ½” thinner than the Hayden, so it fits between the radiator core and the rack, and nestles in as if designed for the aluminum radiator I bought from Speedwell - which is patterned after stock.

However, it pulls roughly 50% more air than the Hayden 10”, and of course draws through a much larger area of the core. My temp needle swings down visibly faster when she kicks in. Also, Spal makes a programmable fan controller than ramps up the fan’s rpms from 50% to max speed between two temp settings of your choice. Pretty neato – though mine just kicks in at 185 and shuts off at 170 with a through-the-core probe and simple relay. Works fine for my ‘cool her down in slow-and-go’ purposes.

Here’s a link to one reliable vendor, though you can find it for even less if you surf around a bit (it’s over $70 on Spal’s website).

http://www.jaycorptech.com/pc-201-14-spal-11-curved-blade-slim-pull-fan.aspx

I'll email pics to whoever wants them.
JM Young

Sorry - forgot to mention the manifold cooling fan I mounted in parallel to the radiator fan: it's a Spal 5.2" Low Profile Pusher (30103013) shoving 313 cfm, and mounted just forward of the stock carb heat shield. I put a 'spring/summer' switch by the relay, so in hot weather, I close the heater tap and throw the switch. Whenever the radiator fan comes in traffic, the manifold/carbs get a cooling blast of air from the little pusher. In 100+ New Mexico heat, it really helps her stay cool at stoplights.
JM Young

I prefer to set my fan to kick on at a temperature just above that of my thermostat so that the thermostat can do its job, only calling on the fan when things are going beyond its abilities. Granted, in New Mexico you see a lot more of that than we do in northern Illinois ;-) Plenty of justification for that Speedwell radiator, too!
David "probably no salt on your roads just now, either" Lieb
David Lieb

As Gryf mentions, the fan blades are curved to be more efficient in the intended direction. If you reverse the direction not only will it be less efficient, it will also be quite a bit noisier.
I bought a Kenlowe new in the box for my Sprite, fitted it according to the instructions, removed my original blades as recommended in the instructions and set the cut in at above normal so as to allow my engine "to work more efficiently at the higher temperature", they said. Drove it in the summer nervously watching the temp gauge until it eventually blew the head gasket. I refitted the original fan blades and now don't have any overheating problems, but that seems to defeat the object of fitting an electric fan in the first place.

Bernie.
b higginson

In relation to the fan direction, it matters little if the fan is mounted in front or behind the radiator, so long as the associated ducting is sealed so that air must be directed through the rad core, or pulled through it. What you do not want is for air to spill around the rad, or be drawn in from the sides. The other key thing is that the curved side of the blades faces the front of the car as that is the side you want them to scoop the air from. Finally check the polarity. Presumably, being a DC motor, if it rotates the wrong way you just switch the wires over.
Guy Oneandahalf Sprites

Revotec, off ebay, £45. Fitted in front of the rad (so blowing through it), thermostatically controller (nice, neat fitting) works a treat on hot days in city queues and good support from Revotec when the fitting on top of the thermostat went awol.
Recommend it alongwith a thermostatically controlled oil cooler.

Jeremy
Jeremy 3

Being a real budget minded guy (cheap) if you have the ability to weld and make your own bracketry I'd vote for a fan from the breakers. I've used one sourced from a BMW on my car for years without problems, puts out a lot of air and cools the V6 fine. It's mounted as a pusher and was mounted the same way in the Bimmer as a secondary fan for the AC. It's a Bosch unit. I figure that if the high dollar luxury car builders would install one and trust it for the warranty period that should be better than most aftermarket units. Use a good 30amp rated relay and you shouldn't have any problems.
B Young

Guy and a half,
I do not agree with your position. If the fan were always on, you would be reasonably correct, but it ain't. Mounting the fan in front of the radiator means that it is actually blocking a significant portion of the radiator whether it is on or not and, this being on the high-pressure side, this is far more significant than an equivalent amount of blocking on the back of the radiator where the heat has already been transferred to the air and the air is getting highly frustrated trying to find an exit from a Spridget engine compartment. I would never have thought of it in this way myself, but an engineer friend of mine who happens to race a Sprite and have a degree in thermodynamics pointed this out to me. Not saying that a pusher cannot do the job on a Spridget, merely saying that, given the choice, a puller is more efficient.
David "most fans aren't thin enough to give you the choice, even with a 1500 shroud" Lieb
David Lieb

Ill. David,
That is why l started off with: "ln relation to fan direction". I didn't mention efficiency.
Guy
Guy Oneandahalf Sprites

Having been sent the wrong direction fan by the manufacturer and not knowing this until after I’d fitted it I gave the matter of location some thought

First thing I resolved was in future to not only check if the fan powered up and turned but not to forget to also check the flow direction is correct - before fitting

I’ve found that my crossflow rad is over efficient when travelling say above 40 mph but the engine soon heats up at say below 20-25 mph and more so the lower the speed below this

So having the fan in front of the rad probably helps a bit above 40 mph by blocking off a bit of the rad and whilst this is a hindrance below this speed the fan will need to kick in anyway and as it’s thermostatically controlled the pro outweighs the con (on the crossflow at least)
Nigel Atkins

’73 Midget
My parents bought me a Clova electric fan for Christmas ’78. Fitted it soon afterwards and only one failure since, blown fuse. Struggled a bit in central London last June, but otherwise not bad at all. 40 mpg on a run, so must be helping somewhere along the line!
Simon
S Holt

Good news Simon, I don't think life would allow me anything on a car that would be that long lasting and reliable

Perhaps it wasn't your fan but your coolant or the rest of the cooling system struggling making the old chap work harder than he needed to :)

I don't know if it's my fan or uprated alternator that causes extra work for my engine when the car's fully warmed up and stationary
Nigel Atkins

My electric fan (from a rover 200) is in front, just behind the horns. it blows backwards thru the rad, and even out through the front a bit and downwards. From that I reckon it's flowing more air that can reaonably go thru the radiator, pressurising the area in front and being nice and helpful. It only comes on when the car's been sat idling for a while, and even then only for about 5 mins before the temp goes back down again.

rather amusingly when i'm driving along the fan rotates by itself , presumably causing less resistance than would first appear?

I can see the advantage of a switch so you can leave it on for a bit after a run, mine always heats up alarmingly after it's turned off.
Rob Armstrong

Nigel,
I would have to say that your thermostat is not operating correctly. The temperature of the water in the radiator should not be affecting the normal operating temperature of the engine.

Guy,
You are correct, you did specify direction. I must console myself with the thought that someone else will have misread it as well ;-)

Rob,
The fan's rotation also creates turbulence which is not good ;-) Now if you could get it to charge your battery for you so that you didn't need to run a power-sucking alternator...
David "who was that girl behind John Bishop on Top Gear?" Lieb
David Lieb

Rob
I wired my fan to be on regardless of ignition as at the time I thought the fan might be causing the car to run on slightly then forgot to check as the run on stopped and never swapped back to need the ignition on

so my fan cuts in sometimes a few minutes after I've parked the car and I like it that way especially during the summer

David
you've lost me, I'll have to see what I wrote to make you put that after I've had my tea

I did notice that all the girls at the front of the TG audience but not one in particular

I think they've been putting the pretty girls to the front for quite some time - just shows the power/influence/decline in civilisation that good looking girls would want to be close to stack of s**t like the three that host the show, well really one huge stack and two sycophant (whoops, did someone mention TG whilst I was in the room)
Nigel Atkins

Nigel,
If going faster makes your car warm up more slowly, there would seem to be an issue with the thermostat, since the radiator should not even enter into the equation until the engine has gotten to operating temperature.
David "if you don't like your presenters, you should watch ours" Lieb
David Lieb

David,
We have been through this debate about whether the fan is better in front of or behind the radiator so many times!

I am very happy to accept the physics that it is more efficient behind the radiator. But if you live in a "cool temperate" climate as I do, and have a cross flow rad, then my car is not prone to overheating. The efficiency of the fan is no longer, for me, the deciding factor. The fan I use is a Rover 400 fan from a scrapyard. It cost £5.00, the thermostat switch was also from the scrapyard and cost £zero. The most expensive bit was the plastic adaptor that the thermostat screws into which IIRC was £14.

So, keeping within that £20 budget, the fan, together with its mounting shroud fits most neatly and easily in front of the rad. The space gained behind the rad makes working on the engine easier and the whole system works perfectly well enough just like that. The fan rarely comes on anyway; probably most often after a run when I switch off the engine. If it does come on in traffic it brings the temperature back down to normal within about 2 minutes so is clearly working well enough. In recent years summer peak ambient temperatures here have rarely been above 80 deg F. And if global warming were to increase this, then I still have the option of relocating the fan behind the radiator to further increase air flow.

I don't expect you to change your view, but it does depend on your priorities. A bit like the Big-enders and the Little-enders we will just need to agree to differ.

Guy
Guy Oneandahalf Sprites

Yeah, Guy, you don't ever expect to drive across the Mojave Desert, do you? I have to keep my options open, so my Midget runs a modern high-efficiency core in that crossflow radiator with an electric puller fan. With the standard core and mechanical fan on a 1310 that probably generates rather more heat than stock, I was ok up to 85 F or so, but heat-soak would set in at temps above that. With the current setup, overheating is becoming a distant memory. One of the problems British cars of the 50's through 70's had in marketing to US customers was the fact that the engineering did not worry enough about non-English climates. Sure, they worked fine in England, but they were prone to overheat here.
David "hot stuff" Lieb
David Lieb

I have just clicked onto the Kenlowe website and the opening page shows a moving image of a fan which seems to be rotating in the wrong direction (concave profile of the blades as the leading edge)which is the opposite to what my fan does.
www.kenlowe.com

Have I got it wrong?

Dave
D MATTHEWS

David, no sorry it's my bad description I meant it heats up above the normal fully warmed running temperature

Dave I think the drawing perhaps a crude illustration only (having just looked at my bathroom extractor fan)
Nigel Atkins

Are your rover 200/400 fans suckers or blowers?
I have just been down the breakers yard to get a fan and they were all suckers and I was not sure that they would fit between the rad and engine.
Also how did you fit them to the rad/shroud?
Thanks for you help.
Dave
D Brown

Dave,
This is the unit I used - see photo.

I used the thing complete as shown - I think I then had to trim the shroud a little before mounting in front of the rad.

Guy


Guy

And as installed.

(I should add that the wiring has since been redone and those horns re-located to clear the air flow)

Guy


Guy

Thanks Guy.
Got to get to the breakers again next Saturday.
Do you have any idea what the internal diameter of the top hose is? I need to get a revotec thermostat.

Thanks
Dave
D Brown

1", 1275 cross-flow rad. Pretty sure they are all the same though.
Guy

This thread was discussed between 04/01/2011 and 13/02/2011

MG Midget and Sprite Technical index

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