Guys
I have two aftermarket electric fans in place of the OEM electric and OEM mechanical fans. They are both 14 years and about 60,000 miles old. The OEM electric replacement is a 12 inch and is wired to come on all the time the aircon compressor is engaged - which is nearly all the time in summer.
The cooling system is in really good hsape as far as I can tell, and the airflow mods I have done mean the main electric fan never cuts in except on really hot days in stationary traffic. This is partly because the smaller fan is enough to cool the engine, even when stationary, in all but these circumstances
Well is it 7 C below here, bright and cold and I gave the car a run a few days ago. Then went to collect No.1 son from school and had to wait, engine running, for 20 minutes, and the main fan cut in - much to my surprise. The reason being it is so cold that the aircon sensors think the cold side is plenty cold enough without requiring the compressor to make it any colder. Therefore the main fan eventually started up on its thermostat.
Now to the point: The main fan threw a really heavy, low frequency vibration through the car. Now this was a surprise, as I regularly test it using the cabin manual override switch, and the fans are mounted in a GiF designed and built chassis, all on rubber cotton reels as used OEM to mount the oil cooler/condenser joint and also the OEM fan shroud. So the next day I tried it again using the cabin switch, and no vibration, but after a few mins, the vibration started up as the fan motor (presumably) warmed up.
So I pulled out the fans and found that the main fan had a great deal of wobble play on its bearings, and the smaller fan had too, although it was not making any vibration through the car.
I happened to have in the GiF parts hoard two SPAL fans, brand new, bought in a previous incarnation before poverty struck, so out they came. One 12 inch and one about 16 in diameter. Naturally, the fittings were in different places and at different angles, so much fettling had to be done to get them to fit. My mounting system consists of the top of the fans being bolted to a 20mm square ally tube which is bolted up in rubber mountings to the rear flat part of the radtop panel. The bottom fixings connect to four welded studs on the crossmember below the rad, also in rubber cotton reel mountings.
All this fettling with endless in and outs to adjust, took about two days in the cold, but eventually in they went. One big advantage of the SPALs is that they are thinner front to back, so go in and out easier and also give extra welcome space in front of the engine. A good tip is to glue the fan-to-mounting plastic mortice joint pieces supplied with it, as otherwise the fan can work its way out of the plastic fixings.
The control system for the main fan is as recommended by Grant. The OEM temp switch in the water pump inlet switches a heavy duty relay to start the large fan, a second heavy duty relay (for extra reliability) is used to activate the main fan by the cabin switch. One GiF tweek is to replace the OEM thermostatic switch by one that comes on at 90 and off at 85 C, as I was experiencing too frequent ons and offs with the OEM temp switch.
Anyway, on the third day I started it up and NO vibrations, fans worked, and undetectable whether they are on or off from the cabin. Pics attached of the old fans and the new ones, installed in their chassis, including fine view of the GiF toes!.
Greg

 

Hi Greg

Nice Job, those Spall Fans look the Business!

 

Sounds like a good plan Greg...

 

Hi Greg,

slightly envious, I am still on original mechanical plus small electric cooling.

would love full electric fans and believe Spal make some of the very best quality fans.

 

They do, SPALs are used on all the current supercars, Astons, Bentleys, Ferraris etc. They are still made in Europe too. Also, in the great scheme of things they are not stupidly priced either, compared with other decent but less superb makes. You also get rid of a drive belt, get another few MPG, and the car is significantly quieter too. You can ditch the OEM fan shroud if you want to, like I have, or keep it if you wish. My belief is that with dual electrics you are better off without it from the engine bay cool airflow promotion point of view. remember that the electrics have their own circular shroud round the blades so an extra one is redundant. However welding some studs to the bottom cross member and the ally strut across the top secured to the top panel was a brainwave, since doing that the fan fixing is just superb. No rattles, or vibrations in the cabin at all.
The minuses are: best to fit a 115 amp alternator like later V12s have; wiring the big fan up so it is reliable needs care and a 70 amp heavy duty lorry relay for long-term reliability (these are easy to find); I floundered about with all sorts proprietary thermostatic switching systems - all of which were useless and inconsistent - until Grant Francis (bows low, kneels and genuflects to Southern Cross) told me how to do it using the OEM temp switch in the pump inlet. If you decide to go for it, do not hesitate to post for details and save yourself some grief.
Greg

 

As a fan of Efans. Apologies, I could not resist to engage my penchant for word play!!


Nice job. The curved blades effectively increase the ability to move air within the same
space. And possibly quieter operation. The former, I get, the latter, not so much.


My "Lump" enjoys a pair of "old tech" straight blade fans. PCM controlled. I like them.


Carl

 

Is it my imagination or are the blades on that old large fan offset, that could have unbalanced the fan and caused the vibration.

 

No, it is not your imagination. The blades are set like that to avoid blade drone. If you look at any original mechanical fan blade from an HE in the 1980s, the cream coloured OEM one, you will see that they are the same.
The fan for years was 100% fine, in fact one of the reasons I fitted a cabin telltale LED to the main fan circuit was because that was the only way I could tell if it was going or not.
The fan spindle bearings/fan blade to spindle fixings were the problem, you can rock the fan blade tips up and down about half an inch!
Greg

 

What size were your old fans Greg? You say one was 12inch, how about the other?
Also how do you find the noise from the Spal fans? I've heard they make quite a roar. Great to see some pics. I still have mine to do.

 

What size were your old fans Greg? You say one was 12inch, how about the other?
Also how do you find the noise from the Spal fans? I've heard they make quite a roar. Great to see some pics. I still have mine to do.


The old fans were Pacets. The large one was 17 inches (called a ProFan, the biggest and most powerful they made at the time, and still available) and actually just a bit too big to go in that easily. So I bought the SPAL replacement a bit smaller, overall it is about 2 inches less in diameter. The large Pacet pumped a huge amount of air, but the central drive spindle was not that well attached to the blade, I actually had to thread the shaft and put a thin nut on it to prevent the blade coming off, as the circlip arrangement was not strong enough for the fan's power. It soaked up well over 20 amps. The large SPAL probably does not pump quite as much air, but it should pump plenty, come the summer traffic I will find out!
Noise-wise, the SPALs make a more high pitched motor whine, but both are inaudible from the inside of the car. The SPALs seem better constructed at the fan attachment.
Greg