On a recent trip my 91 4wd townie decided to suck up the small removable piece of the rad shroud and shred it into 4 million bits along with three blades of the fan,no damage to rad though(lady luck must have been shining down on me that day).
My query is what am i best replacing with,another mechanical fan or go for the electric option,any advice from anybody who has gone down this path please as i have a few thoughts before commencing,
1. Have you found any significant advantage with an electric fan set-up?
2. What kind of fan did you use-is there a kit or can i source one from a breakers yard?
3. Did you wire it into the cooling system or manually to a switch?
Reagrds
Pete
- (#9588) pete, 10 Jul 03 13:24
Take a look at my webpages on this subject, it'll talk U through the leccie fan option.
http://www.robdrinkwater.pwp.blueyonder.co.uk/RJD Computers/towniepics.htm
- (#9589) Rob Drinkwater, 10 Jul 03 15:33
As long as it can move the required amount of air and you wire in a manual override switch on the dash ( its nice to be able to turn it on if you have a paranoid moment), i would go electric and take advantage of the extra mpg/power released (5-7%)
- (#9590) Mark, 11 Jul 03 16:42
Hello Pete
A note of caution here is that if part of the radiator shroud is missing along with three of the fan blades, which solution you decide on should be completed before you drive it again. Apart from the engine shaking itself apart due to the unbalanced fan, the cooling ability of it is now seriously compromised, and could lead to something more expensive adding to your woes.
There’s probably not much to choose in price, but the supply of bits could be a factor. If you get really lucky, there may be a breakers near you that will have a shroud and fan. If I remember correctly an electric conversion will set you back about £150 and my sieve like memory recalls that someone recently found a replacement fan blade for £90. The shroud could be a harder find, unless someone who has already converted to electric still has theirs.
Good luck
dave Bright
- (#9591) dave Bright, 12 Jul 03 4:28
i got a spare fan and the upper part of the shroud
e mail me
adgo6@aol.com
- (#9592) j adgo, 12 Jul 03 6:49
Cheers for the ideas guys,thx to 'j' for the offer of your spare fan but ive decided to go with the electric option and have sourced a fan from a TD Mondeo for a tenner which fits across the rad near perfectly after a bit of modifying with the hacksaw.
I've got it wired through a relay to come on with the ignition at the mo but want to run it through a temp switch which i must ask Rob where did you get your temp switch from as all my local motor factors give me the gone out look when i ask,also how much did it cost?
While on the subject of temp switches can anybody tell me what the two sensors on the water inlet(right side of head) control? i understand one controls the fans on the a/c condensor but the other one on my bus does not seem to do anything - could i poss use one of these to operate my fan relay?
Any help greatly appreciated,
Regards
Pete
- (#9663) pete, 15 Jul 03 11:09
the other sensor on the outlet is a cutout for the a/c- it turns the a/c off if coolant exceeds (IIRC) 112c. The temp is marked on it. You can disable it by shorting the wire to earth.
If you go to your local factors, you should be able to find a more suitable sensor to go in it's place. Or go with an adjustable capillary stat from Kenlowe, or your local domestic appliance parts dealer- an oven stat for example.
I ended up using a switch for a Daihatsu Charade diesel, screwed into the outlet neck. Lucas reference is SNB794. It's 3/8"taper thread seals nicely into the M16x 1.5 tapping in the neck, operating temp is on 100c, off 95c.
You might want to investigate using a ballast to run the fan at low speed at all times- something like a headlamp bulb in series with the fan, then the thermal switch closing a relay accross the balast to give full speed when needed. I even had another little thermal trip on the rad so that the low speed would only start after the thermostat had opened...
- (#9664) david miller, 15 Jul 03 11:54
Pete. I have stuck with the viscous fan for over two years and, over a year ago I replaced the viscous coupling just to make sure that everything was working well. I have never had any problems but, I do run on a modified Toyota thermostat, the Toyota pattern filler cap, and much attention to the cooling system. However, in this very hot weather, I find that the viscous fan is "engaged" most of the time, though my Durite gauge tells me that the head temperature never exceeds 95c. The downside is that the "roar" of the fan, is quite irritating and, worst of all, there is a marked loss of power, probably, I think, exceeding that 7% already mentioned. As someone who has, on occasions, been a bit cynical about these 2lt engines trying to move 1.5 tonnes of metal, I am considering putting in an electric fan. Can anyone say if their available power was noticeable after discarding the viscous fan?
- (#9665) John Davis, 15 Jul 03 14:05
To move sufficient air past the radiator to maintain cooling requires power. This power (7% of engine power is mentioned) has to come from somewhere! This equates to many kilowatts. When a viscous coupled fan is operating ("roaring")max load is applied to the engine. If we now compare shifting the same ammount of air with an electric fan then as losses are similar we will need to use a similar power to drive the fan. As 8.3 amps are required per kilowatt then we are talking about 25 amps or more to supply the fans. This can be a tremendous load for the alternator especially at night with lights and heated rear screen on. Expect the alternator to die as it was never designed for such a high load. Also worth noting is that the extra power needed to turn the alternator still comes fron the engine with an increased power conversion loss. Now consider using a fan that draws alot less current. This fan will not move as much air as the original and this may lead to premature overheating. Masterace owners please be aware of the air intake on the front of the vehicle is frequently covered by the UK style number plate. You are allowed to fit motorcycle sized plates on imports like ours. Tests carried out by me have shown a vast increase in airflow when the plate was replaced and now the "roar" is only heard when sustaining 70+ or when flying up hills! I think this is more acceptable than fitting a lower powered fan. 10000kms done since moving number plate and less than Half a pint of water needed to maintain the correct level. Would Toyota not have fitted a dedicated electric fan to the main radiator if it was better than a viscose unit. I rest my case!!
Your thoughts please...
See you at Woodvale... Ray
- (#9666) Ray, 15 Jul 03 18:09
Been there, done that, bought the "T"shirt. My townie (as modified) is being run by the selling dealer, and he thinks it's great. Doesn't overheat, loadsa power, temp gauge that works. Best he's driven, apparently.
Ray, automatic townies have a well- sized alternator (70A- ish) and you must bear in mind that as marginal as the cooling system is, the fan doesn't run continuously.
The system I had installed in mine using the single Pacet fan- their most powerful at the size, and certainly the highest-flow fan I could find after much searching, would use around 10A at full speed and 4A at low speed. The fan was so efficient that I had to call their tech. dept to confirm it wasn't faulty as yes, similar sized fans were rated at 20-25 A...
Anyway, with the fan running at a slow speed at all times there was sufficient cooling around town, the high speed only cycling on (about 1 min on, 2 off) in times of heat soak or hard motorway work.
The small front plate does help tho...
John, yes, the electric fan does free up measurable power. More noticeable is the improved fuel consumption.
Why did they fit a viscous fan? Dunno. More cooling capacity in the tropics at low speed- big fan swung by all the engine's power, is my best guess. Lots of reserve power at low speeds. But in our environment, we see overheating at HIGH speeds, when most of the engine's capacity is being used to cut the wind. It's my belief that the drain of the viscous fan in these conditions is CONTRIBUTING to the overheat.
Remember that alternators are very efficient things- 70A will only be taking 2HP or so off the engine (12x70=840W x say 80% efficiency= 1050W, and there's what? 760W per HP...)
- (#9667) david miller, 16 Jul 03 1:20
Thanks David & Ray for your most informative replies where you both put forward very cogent arguments. If I am truthful, I want to do the electric fan conversion as an experiment so, I will probably go ahead and, as Rob advises in his splendid webpage details, ensure that the viscous fan assy is not discarded, just in case a retro fit is required.
- (#9668) John Davis, 16 Jul 03 2:03
Why did they fit a viscous fan ? Its because the van is marketed it a different climate than ours i.e. hotter at times (may be not after the last few days) higher humidity and lower road soeeds mean that the air flow is reduced, also incase someone loads it up to capacity and drives it across a desert. It the same argument for 4X4's, defenders have a viscous fan but most people wouldn't drive them up 45 degree muddy slopes revving the nuts off it doing 10 mph, cruiseit around at 60 and the fan is never used...
- (#9669) Mark, 16 Jul 03 12:58
THX David for the info on the temp switches,shorted it to earth with the a/c running and it cut out,so it must be working after all.
Have decided to go with a capillary switch from Kenlowe to operate my fan,any ideas on best temp to set it up to switch on the fan?
Have just ordered a temp gauge alarm from Dave and hope to be fitting that this weekend so i can keep a better eye on what the temp is like.
In answer to John's question on noticable power increase I must say that since i ditched the viscous fan my bus accelarates a lot better and seems to give a much smoother range through the gear changes - dont know about improved MPG yet but have to go on a 400 mile round trip this weekend so will be recording MPG and comparing with a fortnight ago when i did the same run with viscous fan fitted,will let you know results.
Regards
Pete
- (#9755) pete, 18 Jul 03 13:03