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Section : Cooling

Electric Fan

Posted By : David Freeman, 15-Dec-2003, 09:09pm

Many years ago I was putting the finishing touches to a kit car, tuning the noisy thing at the front, and got so carried away with the zoom zoom sound that I completely 'forgot' about the metal fan spinning around just aft of the radiator. I lost lots of skin and had two fingers painfully wrapped in plaster for weeks, and have never forgotten the experience.
For my sanity's sake, I now wish to put an electric fan in my Herald, and have found an Australian make at Think automotive at half the price of the usual Kenlows.
My question is...what size of fan must I choose? What diameter are the Kenlows suggested for a Herald narrow type rad?? Does it matter if I buy a biggish one which will fit as it will cool the thing more efficiently, and quickly, or will a smaller one run for longer and make more...er noise?? What does the team think?

Followups :

Electric Fan

Posted By : William Davies, 15-Dec-2003, 10:20pm

Hi David,
An electric fan should NEVER be fitted to a Herald with the narrow radiator, the fan body will obstruct airflow through what is already a marginal radiator.
Your reasons are somewhat different to most people's, but I have never encountered a Herald which has needed an electric fan - they are normally fitted in a vain attempt to fix an unrelated fault.
Cheers,
Bill.
- Electric Fan
  
  Posted By : David Freeman, 16-Dec-2003, 09:43am
  
  Bill:
  I understand the issue, and thanks for your comments.
  I would like to mount an electric fan engine side of the rad to suck the air through. Naturally I will remove the original fan and spacer the rad forward only about half an inch so the hoses will reach and enough space created.
  Further comment?
  - Electric Fan
    
    Posted By : William Davies, 16-Dec-2003, 10:00am
    
    Hi David,
    You will restrict airflow by doing this. Putting the fan in front of the radiator would be even worse, but what you are planning WILL cause problems with airflow.
    Cheers,
    Bill.
    - Electric Fan
      
      Posted By : Savvas Regas, 21-Dec-2003, 01:58pm
      
      Hi
      
      There appear to be more holes than obstructions in the suggested fan from Think Auto.
      
      http://www.thinkauto.com/
      
      I am not sure why Bill says it will restrict airflow.
      It must be beneficial to have a thermostatically controlled fan, ensuring faster engine warm-up in cold weather, better cooling in heavy traffic and a more free-revving engine.
      
      Cheers,
      sav
      - Electric Fan
        
        Posted By : Nigel Gibbins, 22-Dec-2003, 10:44am
        
        Bill is right, it will restict airflow when you are driving - all fans that sit in front of the radiator will do this as they have to sit snug against it.
        
        The reason being that in the centre of the fan there is a CD sized motor which will shroud the radiator and when you are driving. This of course will reduces the effective size of your radiator (can be by as much as 12% smaller) you may find your running temeratures (while driving) are somewhat increased.
        
        Even when the fan is running the centre of does not push any air and effectively gives you a 'cold spot'.
        
        Just imagine how effective your radiator would be if it had a 'cold spot' of the same size or a sludge buildup of a similar size!?
        
        I'm not entirely convinced about the 'faster warm' up as your standard thermostat will shut off the radiator until the engine reaches a certain temperature anyway (dependant on thermostat rating).
        
        However, it will reduce engine noise, give a free(er) revving engine, slight power gain. Better cooling... possibly but thats really down to your radiator condition and size.
        
        I wouldn't fit one to my road car (I don't have one at all on the racer) but then I wouldn't remove it either and infact my GT6 does have one, but was getting dangeroursly hot this summer when motorway driving.
        
        The choice is yours
        NiG
        http://www.niginthecar.net
        racing@tssc.org.uk
        
        Electric Fan
        
        Posted By : Jason Chinn, 22-Dec-2003, 03:14pm
        
        Hss anyone done much work with electric water pumps - it occurred to me that with a electric water pump and a thermostatic controller there might not be much need for a fan at all - never tried it but I'm tempted.
        
        J
        
        Electric Fan
        
        Posted By : Nigel Gibbins, 22-Dec-2003, 03:57pm
        
        I have the Electric Water Pump on the racer and as I said before - no fan. However, I would not recomend this for road use as the heat still builds too high when the car is stationery. If you hit traffic without a fan you are going to cook your engine.
        
        On a racer we're never stationery that long so you can get away with it.
        
        NiG
        
        Electric Fan
        
        Posted By : David Freeman, 22-Dec-2003, 06:39pm
        
        Thanks all for your comments for and against fitting an electric fan. I've fitted a 12 incher behind the rad and moved the said rad forward an inch or so. The fitting kit suggested threading these long thin bolts through the radiator, but I didn't fancy that, so we fabricated a metal frame and attached it to the existing edge mounting points. The thermostat is in, and an extra switch for
        'permanent on' concealed beneath the dashboard.
        The underbonnet look of the setup isn't brilliant, but I'm hoping that it will work better for me in the long hot summer months in the very slow London traffic.
        Now then, I really must find some tan leather MX5 seats....
      - Electric Fan
        
        Posted By : William Davies, 22-Dec-2003, 09:32pm
        
        Hi Sav,
        Why so I say it will restrict airflow? Experience, that's why. Having owned over 40 Heralds of my own, and having helped sort out owners problems, electric fans mean nothing but trouble when used in conjunction with the undersize radiator. As stated by others, faster warmup shouldn't be an issue as that's what the engine's thermostat is for. Even with the fan behind the radiator, the electric motor acts as an effective obstruction to the airflow - the radiator doesn't have enough cooling capacity to manage with this blockage,
        Cheers,
        Bill.
        
        Electric Fan
        
        Posted By : David Rumens, 27-Dec-2003, 12:54pm
        
        Just my thoughts - I agree with Bill comments about electric fans when used on Heralds. The main the major advantage being winter use and fast warm up. In these condition you will save power and not overcool the engine.
        
        However, power saving is somewhat over stated as the conversion from mechanical to electrical and then back to mechanical energy is very inefficient. Remember the electrical power is not free, it is taken from the engine power via the generator.
        
        In hot weather or when using the engine power to the full the electric fan will be in use. The power used by an electric fan will be greater than the standard mechanical fan, this being due to the conversion inefficiency. This also goes for an electric fuel pump or water pump.
        
        The other point is by using a directly operated mechanical device you are eliminating the electrical process and this will be inherently more reliable.
        
        I found a full length rad and normal fan fitted to my Herald worked very well during last years very hot summer.
        
        Regards
        
        Dave
        
        Electric Fan
        
        Posted By : Ben Watson, 18-Jun-2006, 10:50pm
        
        Although i agree with almost all of what bill says almost all of the time (experiance is better than a haynes manual by far!)
        i also like to hear of people thinking outside the box as it were, and having done an electric fan conversion myself (a mk1 fiesta unit) i have certainly seen the benifits (although i have a full width rad)
        in my experiance i have found that you have to choose wisely as to which fan kit to fit as bill says some will block too much rad causing problems, always fit an over-ride switch and a temparature guage just in case, and a full width rad is the best option, but above all, as with any car make sure what you start with is sound otherwise your fighting a loosing battle, ie: in this case a radiator in good condition with no chunks out of the elements and it should be totally sludge free, as with the rest of the waterways.
        
        cheers
        spug