All four blade fans are NOT equal especially some of the after market.  Find an original OE.  20F difference.  Also have been making our own even smaller pulleys for 25 years.  Works for us.  Not science,  dumb luck I guess.  

It's my opinion and I'm too old to change my mind.

Kerm

So I know the super 2 core wasn't blocked because it was only a year old.  I think the smaller pulley is doing the trick with the aluminum radiator.  I am sure I would have had the same results with the super 2 core.  With the extreme temperatures usually around 97 degrees F I am now running about 90-100 degrees C.  This morning I took the car to work and it was 78 degrees F and I was running between 80-85 degrees C.  I think I will hold off on the 4-blade fan since I will be relocating soon to Anacortes WA and the weather there is much more tolerable with no worry of altitude.  Thanks for everyone's inputs!

Mmm that's not true either why do Propeller driven airplanes use a feathering devise if the engine stops? It's because the rotating Prop. causes drag more so that when stopped, when it's not rotating you have the blade area causing drag but if you rotate it it becomes a large disc in the way of the air. Hence feathering the prop. The same would apply to the Fan on your radiator? 

"Not quite 100% correct" either, John.
If the electric fan is turning without being powered, then it is the air pushing against its blades making it turn. That air is coming through the rad and trying to find an unrestricted escape. However, it meets the fan blades. The proof of the air pressure and hence resistance it meets is the amount it turns - enough to generate electricity, albeit low amperage. I have no idea what kind of filament bulb you used, but it probably wouldn't glow below 9V.

If, as you say the electric fan pulls well through the rad, then logic suggests there isn't much space for air passing through the rad to by-pass the electric fan. If the face silhouette (the shadow it would cast) of the fan is, say 60% solid, then if it didn't move, it would block the rad 60%.  Since the air movement does turn it, you might estimate its net blockage or negative efficiency at say 50% (when you consider the turbulence it would generate in the unrestricted airflow), the net effect would be a 30% blockage of the rad face. 

It isn't pulling air from the rad. it is inhibiting its flow.

A turbo-jet engine works somewhat on the same principle. Up front is a big impeller fan that pressurizes air into the engine. At the tail end is a smaller fan driven by the exhausted air flow. Its primary purpose is to drive the impeller. The point is, it makes use some of the engine's output to do work (much more than your indicator light!).

"- an electric fan on the rad, if not turned on at speed, would act as a restriction to airflow through the rad, reducing its effectiveness."

Not quite 100% correct, Dan - T'would be true if the electric fan didn't rotate passively when the mechanical fan is blowing/cold-air is flowing through the radiator.

My (Check out the link: C-ARA4401) electric fan is mounted to the radiator, true, but the 'blockage' of air flow through the radiator past the electric fan's hub is negligible.  In fact, the passively spinning blades also draw air through the radiator.  

When I installed my electric fan, I opted for a toggle switch instead of the in-hose thermostatic switch.  Additionally, I used a small BA9S filament lamp to indicate when the fan was switched on.  When rapidly accelerating to 5 or 6 thousand rpm, the dashboard lamp would become illuminated, indicating that the fan blades were spinning and generating electricity.

This particular electric fan is by far the most effective electric fan available as it draws directly through the radiator, and not the airspace between the inner wing and the radiator.  

Some "unsophisticated" (AKA "keeping it simple") observations:
- the 11 blade plastic fan works at least twice as good when facing the right way.
- the plane of the fan needs to be within the opening of the rad shroud to be really effective - the right thickness of spacer is mandatory.
- an electric fan on the rad, if not turned on at speed, would act as a restriction to airflow through the rad, reducing its effectiveness.

Um, I have an 'S-type' harmonic damper on the crank; my 998 engine isn't stock.  I've got the breather on the tappet cover, so, yes, the timing cover is clear.  Still a tight fit though.  I use the 1/4" spacer between the pump and pulley.

OK, with the heater connected up, you should be able to see on the gauge the effect of running it full speed with flow from the valve on the corner of the head, through the heater core and back out to the lower rad hose at the water pump inlet.  I have the tiny aftermarket heater (the core is about the size of two cigarette packs!) and I can see on my mechanical gauge the effect of turning on the heater blower.  You must confirm that your heater valve in the head is indeed closed and you are not simply bypassing the radiator with all that flow.

The "4-blade fan" as jeg uses is not going to be your best choice... Keep in mind that jeg has a 998 in a cool European country!  The very best airflow will be from the "Tropical" 6-blade metal fan, but they do make a racket, and require the most careful clearance around the breather on the timing cover and the lower rad/motor-mounts... again jeg does not have a breather on his timing cover, nor a harmonic damper if his 998 is stock.  The best all around choice IMHO is the 11 blade plastic 12G2129 (installed oriented properly!!).

I still suspect you have another contributing factor here...re-check the basics!  A short list of common 'finds'... You have your electric fan blowing the wrong way, trying to blow air IN, you have your engine driven fan on backwards reducing it's effectiveness hugely, you have a defective heater valve allowing a radiator bypass, you have some sort of body kit that is disrupting airflow at speed, You have some other issue that is making your engine work too hard at less than optimum RPM for highway speeds (something like too much total advance outside the RPM range where your engine makes torque).... It is uncommon for a mini to suffer overheating at speed!

most likely your old radiator was plugged up inside and that new radiator made the most difference

Jemal the heater circuit is original and I only open the heater valve in the winter.  Turns out the 4-blade fan is out of stock with an estimated arrival date of 4 weeks.  I cant wait that long to drive the mini!  I tried an experiment and removed the large pulley, fan, and super 2-core radiator and installed a small pulley, same 11-blade fan and aluminum radtec radiator.  Attached is a photo of my peak temperature at 70mph @ 3500rpm with a temp outside of 97 degrees F.  I can say the cooling is much better but there is room for improvement.  I think the 4-blade fan might provide me that extra air needed.

230 degrees Farenheight!? I bet your heater works amazing ;)

And for the people over the years who said cooling the BIG honda engine is tough blah blah.I have a 7" electric fan that i cAn put my hand around and pick up mounted to my radiator with the pushy things that poke through the fins and snug the fan directly to the radiator.I have a a Turbo which creates heat,and clutters the bay up and i cant even gt the car to see 200 degrees F on a 100 degree day beating it to death.After plenty of pulls it may see 194 i think was the highest ive ever seen and it quickly drops to 180s then dips to 170s and fan shuts off.

Id venture to say those little yellow fans etc dont work too well?? My little fan was rated to flow 1500cfms and it cools very well even being that small.The other fan i had was 10" i think and didnt even cool as good and i wanted to save space so tried this one from amazon.$40 and works amazing.

I know people like stock clutch style fans or w.e and say they push a lot of air blah blah but a GOOD electric fan is awesome and cant beat it.On our mustangs we run the Ford Taurus Fans and Lincoln mark 8 and they flows tons of air and ive NEVER had any other kind of fan evem come close to what they do.Clutch,flex fan,etc nope.

Something besides the fan is awry if you are getting hot at speed!  How is your heater circuit hooked up if it is, and what are you doing with the heater hoses and control valve if not?  I agree that the fan won't matter much at highway speeds. Most Minis do just fine as long as moving with airflow into the grille.  They really suffer in hot climates when not moving, as engine compartment heat diminishes the effectiveness of the air that the fan CAN blow!

I'm in Denmark, so basically at sea level.

Initially, I swapped from the 11-blade fan to the 6-blade + super cool 2-core radiator due to cooling issues.  I have always used either an 82°C or 88°C (seasonal exchange) thermostat and was still using the large pulley.  I've always found the 6-blade fan to be a proper pain-in-the-butt to install.  For the most part, this seemed to work fine.

Then, on the hottest imaginable Danish summer day about 2 years ago, the week before the Copenhagen Historic Grand Prix races, I took the mini out and got stuck in a monstrous traffic jam about 2 miles from my garage.  The roads that I normally drove had been blocked off to create the race course and I was stuck without any means of escape.  It was only about 88°F, but the sun was intense, no breeze and I sat in my black mini, idling with the heater running and watched the temperature gauge climb.  Oh crap - it just passed 95°C (203°F) and not a bit of shade in sight.  It was only then that I realized I might have a cooling problem and proceeded to address it.

My overall approach was multifaceted.  

I installed the Lumenition Optronic optical ignition system to ensure that my ignition timing would be as precise as possible.  I noticed a slight pre-ignition issue which changing from BP6ES to B6ES solved but also realized a slight detonation problem at 2800-3000 rpm.  I spoke to KC (Keith Calver) about my ordeal and he mentioned that he's been re-visiting using the small pulley and suggested that I try one.  I then sent my distributor went off for re-curving at The Distributor Doctor, as 2 others I'd previously had done were no longer suitable for my engine's current spec. and I replaced the head gasket to make sure that the cylinder head hadn't suffered from the temperature issue.  The head was fine and and Keith was kind enough to send a small pulley from his box o'stuff.

I then replaced the heater core and invested in the ultimate electric fan (C-ARA4401), opting to use a manual switch rather than the in-hose thermostatic unit.  Only after installing the electric fan which mounts directly to the radiator, thus limiting the amount one can tilt the radiator towards the inner wing, did I find that re-using the 6-blade fan nearly impossible.  So, ordered a couple of 2-blade fans and succeeded in fixing them to the pulley, tightening the screws one flat at a time.

So really, I don't know if there was one component that was more responsible for the cure than another, as I had a couple of simultaneous factors to address. 


For your mini, try the 4-blade fan with the small pulley and see what happens.  Put new plugs in it (non-projected nose).  Take the mini for a longish highway run, 4000+ rpm, clutch/shift-to-neutral, turn engine off and coast safely to the shoulder.  Regarding the needle, it really depends upon how what you have now is working once you change pulley.

Pull a spark plug, examine with magnifying glass and a strong light.  Look way down deep inside to the base of the ceramic insulator.  The insulator should be clean - no speckles, glazing or anomalies.  There should be a dark grey soot-ring on the spark plug shell/seat which extends about 1mm up the base of the insulator.  

The ground electrode/earth 'tab' should have a slight heat-marked annealing band (small colored 'heat' band, either blueish or yellowish) about half-way between where the tab is welded to the base and the tip over the '+' electrode.  if the annealed band is close to the tip, give a little bit more ignition advance.  If the annealed band is close to the weld, the ground electrode is seeing too much heat and you need to retard the ignition a small amount.  This will give you an indication that your ignition is pretty much correct, but the '+' electrode will tell you more.

The '+' electrode is the fun one - it's the one which will tell you how your ignition timing is adjusted in relation to what your engine wants/needs.  There should be a faint coating of greyish soot on the '+' electrode which extends from the clean ceramic insulator all the way up to the tip under the ground/earth electrode tab.  If this soot deposit stops short (½mm +/- a tad)  and forms a distinctive clean ring at the tip, then you've got too much ignition advance and need to retard slightly.  There may be a lopsided effect from turbulence inside the combustion chamber, giving a 'clean side' to the '+' electrode, so be sure to look at the 'tallest' side of this lopsided blush.

Good luck -

Fantastic article, though it's a bit old and motorcycle-based, it's still relevant:  //www.strappe.com/plugs.html 

I've read through this thread and I must say I'm now totally confused! The altitude thing is one point, is the car getting hot at altitude or sea level? If altitude it should be running a bit rich which should cool things down not raise temps. It seams like your saying it gets hot at cruise speeds? Therefore the fan choice would have little effect on temps. The air flow from forward  motion would be far greater than the fan would provide therefore the difference in fan would be how much it restricts the air flow. Timing should be set at max advance on the distributor regardless of engine speed. Increase revs till you reach max advance THEN set your 28 to32 figure. Did I miss a thermostat coming into this? Or a bypass? Pulley size is relevant to usual rev range if your Revs are high at cruise i.e. Above 4500 large pulley below that small pulley. If you push the coolant through the rad too fast it will get hot! Hence a thermostat poss 160 would help not hinder if you run without thermostat and a working bypass you must use a blanking sleeve or it will get hot. 

In fact I was having this issue last summer but it wasn't nearly as hot.  The distributor issue I was having with timing ended up being a faulty pertronix unit which I figured out much latter than I had wanted to.  No more timing issues for now.  The I hit max advance of 30 degrees by 3500 RPM and its the same at the higher RPM bands as well.  I posted on the forum on that one because the distributor cap was showing burns on two of the cylinders.  I tried the BDR needle but I felt as though the car was sluggish and no real change in temperature.  Maybe it would be worth a shot again since the ignition was sorted out.  Do you know of a needle which would be better suited than BDR?  I ended up removing the small pulley and putting the larger one back on because under 78 Degrees F my temps were normal and I did away with the aluminum radiator and went with the super 2 core because the aluminum one was two big to fit an aux fan to.  Now that summer is here again the issue has returned.  I am going to take your recommendation and install the small pulley and 4-blade fan.  Last night I ordered two of the 2-fan blades from 7ent.com since they were on sale and I hope the extra air flow will help solve the problem.  Jeg im not sure where your located but what kind of outside temperatures are you seeing during the summer?  Did you swap from the 11 blade fan to the 4-blade because you were having cooling issues as well?

Ok, I've looked at your previous thread: https://www.minimania.com/msgThread/118104/1/1/High_Altitude_Driving 




I'm a bit confused.


I'd also like to add that one of the features of this carb needle selection tool is that you can simulate the effect of either raising or lowering the jet - as it relates to changing the annular area.

Yes, try the small pulley and 4-blade fan; it won't hurt to try.

I find it worrying that you're using the same needle that you used at sea level.  Let me guess, you leaned the carburettor to get it to run better when you first moved 'atmospherically upwards' - it was running too rich, correct?

So now, my theory is that you've got a smooth idle (because you adjusted the mixture to obtain it after moving from Sandy Egg.  (I f*cking hate those pop-up emoticons and I'm tired of fighting them.)


There have been several message threads regarding higher elevations and needle selection - try a search for one of these threads.  Additionally, the Mk1 Performance Conversions website has a great needle selection tool which provides not only needle dimensions, but more importantly compares annular area and allows different needle types as well as prototype 'test' needles to be compared against each other.  //mk1-performance-conversions.co.uk/technical_carb.htm  (I helped Ian when he did this latest revision.)

Good luck, we're rootin' for you -

I agree 110 is extremely warm!  I know the gauge is accurate because I tested the temp with an infra red thermometer.  I haven't had an issue with boil over yet either.  The engine is a 1380 set at max mech advance of 30 degrees and im using a BDK needle/HIF 44 carb.  The plugs are BPR7E.  Now the temps are around 100 degrees F here and im at about 4000ft above sea level.  Im thinking these factors could be partially to blame.  I can idle all day and the electric fan will keep the temps at 90 C.  The real problem is when at highway speeds.  Im hoping the 4-blade fan and small pulley might help in this area since cruising for me is usually 3500 RPM at 70mph.  I once tried to mount a 6 blade tropical fan but the fan didn't sit flush with the pulley so I scraped the idea.  If I can get more airflow with the 4-blade fan than the standard plastic one than I think I need to swap it over.  At least until the temps go lower.  Anything under 78 degrees F I haven't had a cooling issue.  Jemal/Jeg  thanks for chiming in to lend a hand.  I never had these kind of issues when I had the car in San Diego.  Maybe its a SoCal thing! 

Wow - 110°C is pretty darned hot! 

Don't know what you've got for an engine; mine's a 998.

I've been using the 4-blade (2 x 2-blade) for years now, just the fans, without the little stiffener square.  I removed the 6-blade fan when I installed the electric fan (C-ARA4401), as there really isn't room to install the 6-blade unit when the electric fan is fitted between the radiator and the inner wing to the front of the radiator itself.  I also made a hot-air shield to block off the gap by the subframe tower between the radiator and the inner wing in order to direct hot air through the inner wing.  This is fastened by two radiator shroud screws.  The electric fan really helps in traffic.

I haven't noticed any loss in power with the 4-blade fan, but there is a bit more noise.  Pushes masses of air, though.

If I remember correctly, I was running about 95° - 98°C (capillary gauge) at long traffic lights and just under that at 5300 rpm (ish) on the highway (minimum 20 minutes to a half hour at a stretch), so that'd be 146kph/90mph.

At the time, though, I needed to have my distributor re-curved; it had too much advance at 2800 - 3000, so I had to retard it a bit to get it driveable around town.  This led to less total advance than was optimal at higher rpms..  

So my multi-faceted cure was to have a distributor re-curved, installed an Innovate MTX-L wideband gauge in order to be 'more certain', replaced the heater core (just to be sure) and at KC's suggestion installed the smaller pulley (heck, he even sent the pulley to me).  I don't know how the pulley performed on its own, but it hasn't hurt anything. 


The deep impeller (cast) is definitely needed, and MSC has developed an improved version which our host also carries. 

Link:  GWP134EVO and GWP187EVO


My recommendation to you is to re-visit your timing and fuel mixture, assuming you've got the right heat-range spark plugs.  Try also a non-projected nose plug (B6ES instead of BP6ES, B7ES instead of BP7ES and so on...) - it helped mine (using stage 3 cylinder head).  If everything's good there, then install the small pulley and try it.  

Neither the 4-blade fan nor the electric are much use on the highway, so it's all down to the water pump's ability to circulate coolant.

I could see the smaller pulley being "better" for cars with a tall final drive, or around town cars that don't see the high speed and high revs that can result in reduced efficiency of the water pump.  And thanks Jeg, I did not realize that EVO pumps won't fit the basic pulley!  I've been recommending those pumps for hot rods, when possible, the GWP154 version without the bypass hose.

But, if you think about some reasons for ineffective cooling, such as running without a thermostat, the Mini can easily flow Too fast through the rad, so if you do try the small pulley, try to make sure right away that it does not make the problem worse.  Also I prefer the 160f/71c thermostat for hot climates as it gives you a lower temp "starting point" as you approach traffic so you can buy a little safety margin as you watch that gauge and wait to get moving again.