Hi All,
Another question regarding the 300tdi auto 110 being built. Considering putting a Electric Fan in place of the viscous one, basically whats the best way , kenlowe, pacet or something from the wreckers?. the 110 will mainly be used for long journeys, also towing a heavy trailer at times.
Thoughts ideas recommendations etc gratefully accepted.
regards Keith

I had a kenlowe in my 90 used once in anger when I soaked the electrics and several times for maintenance checking that it worked


Don't think I matters as to which as they'll all do the job just wreckers are probably cheaper......

I personally would go for the "wreckers " option. By far the cheapest and not too difficult to do. I run a single mondeo fan on my 90 but it never kicks in.It might do now though with the hot weather. Speak to simonr about his hose coupling (x-eng)
ade

Over the years I have fitted plenty of electric fans with very mixed results.
Cheap(ish) Kenlowe with narrow blades - did not blow well then after a year or so the blades started wobbling on the spindle and the fan fell off. If I remember the plastic ties that went through the rad fins eventually broke the rad tube. (new rad!)
Second hand from a scrapper - spend weeks trying to make a decent structure to hold it next to the radiator. Looked a mess but worked really well.
Pacet - bought a nice deep one with wide blades and a shroud. Gave a good blast and while it used those plastic ties 3 years later it was still working well.
If you need a thermostatic switch you must use one like X eng sell - don't even think about any other type unless you carry enough spare water to top up on the roadside while sitting in a motorway tailback.

In my experience, the wreckers option is pretty good.

I like the fans made by 'Gate' used on French & Italian cars. They have big, wide blades and slow, high torque motors. The motors are good for electric skateboards and bicycles too!

Pacet ones seem to be the best of the purpose built after-market fans - if you are keen not to rummage around a breakers yard.

Si

Scrapyard, like Si says the Gate ones are pretty good. If you don't want to get your hands dirty then look on eBay, loads to choose from.

For the control, an X-Eng fan switch gets my vote - for the price it's not even worth trying to do yourself.

Oh and the kenlowe stats are cr*p, they die if you get them wet, ask me how I know

Mondeo fan vote here. my writeup here

Luke

One vote NOT to buy a Kenlowe from me - the one I've got is Cr@p!

I'd have to say though why not just stick with the viscous? In good condition they work the best of all!

Jon

You can't turn a viscous off for wading or force it on to dump heat. If your electric one goes you can bodge almost any other electric one in it's place. Electric one will work with no fan belt. Electric ones don't knacker the water pump bearings (as was the case on my RR when I got it).

But this argument is a bit like the electric/pto/hydraulic winch debate, there is no right answer.

Fitting a kenlowe or Pacet fan to a vehicle that's going to be used off-road even occasionally is a bad idea if you use those ridiculous cable tie thingys that they supply. One's from scrapyards are the cheapest option, and with care you can secure them to your radiator (or nearby)

I have a 13" Kenlowe fan, which has been on 2x109" S3's, and now catflap.
I made mounting bars an the last motor as the cable tie things damaged the fins of the radiator, but it was a bodge job, so I mounted it a bit more carefully this time - making a mount that's fixed, but could equally be removeable. The radiator can now be removed with the fan still attached or seperately as required.
A bit of angle iron and a couple of hours work, so not that difficult really.









The only downsisde to doing this is that you are kind-of commited to buying the exact same fan again if the first one fails for any reason.


Les.

Holding a fan with cable ties to the radiator? You might as well stick a screwdriver through your radiator - be more conveninent than having the same happen where you are not able to replace/repair the radiator.

Get down to B&Q get some right angle steel bracket, tube etc: and bolt together or weld a proper mount for the radiator.

I've got a pacet fan held on to my oil cooler with cable ties, not the things that go through the rad though.



A bit of a bodge, but is does seem secure, intention is to sort a better mounting when I have time, althouth that probably won't happen till it falls off

keep the Viscous fan
to have the equivilant power in an electric fan the blades would have to be 14ft in Diameter,

hmmmm, depending on how one interprets this, either the viscous fan is powerful enough to suck pedestrians and cyclists through the grill, hence why bull bars are fitted ... or it is using up more power than is necessary since an 15 inch electric fan or smaller twin fans can keep an offroader cool.

Jut curious about the source ^^ of this data?

(before the electric vs viscous all out war breaks out, the correct solution is electromagnetic clutch - wasn't simonr tonking one up or was it someone else on here?)

another thing to bear in mind is that viscous fan, sited behind the radiator, opeerates by suction so cannot be as efficient as a push type that sits in front of the radiator. Why you ask? A suction at best cannot generate a negative pressure more atmospheric, i.e. about 14 psi but a push type can produce much higher pressures. (at least that is how it was explained to me).

Just curious really but what sort of air volume does a land rover viscous fan shift?


Edited to say that I ask cos I couldn't find any definate figures when I was looking to compare my electric fans (which I could find any figures for either) with a viscous unit, best I could find was that it was likely to be about 2000cfm.

Direct quote from a Kenlowe engineer
when questioned about the requirements to replace the L/R viscous fan
for one of thier products.
give them a call and ask the question.


And to Mark lots I guess

Both my fans are held on with cable ties and none go through the rad

Mo

Once on pre trial checks, I ran my motor up to temp and noticed the Pacet fan had stopped working, no obvious fault, the motor was clean, good power supply etc, it was only 9 months old on a car that gets used twice a month.

In desperation went to the local breakers, the only thing that was near suitable was a 10" gate fan off a very old Festa, put it on as a stop gap, its never come off!

Works 10x better than the 16" Pacet, less noise and cost £3

Just been given a 16" fan off a transit, on bench test, it shifts some air.

and..



What exactly is meant by "to have the equivalent power"?

It certainly cannot be saying that to move the same amount of air as a viscour, an electric fan needs to be 14 ft diameter - that has to be wrong as any plane buff can tell you.

It is not about power but shifting air. I don't claim to be as knowledgeable as the Kenlowe engineer but my understanding of fans and the amount of air they shirt depends on the area swept by the blades, the shape of the blades, number of blades and the speed at which they rotate.

I haven't looked at a viscous up close but they do tend to be a couple of inches bigger than the largest diameter electric fans I have seen (15 inch) and blade shape plus number of blades is comparable.

I don't know how much difference in speed there is between the two but again since they are made of plastic, sp the max. design rpm is limited by the material (i.e. max speed before it flies apart).

There may be more power avaialable to the viscous fan - limited by belt slippage/breakage than can be supplied by a wee electric motor but it is moving air not trying to propel itselft through Lyons golden syrup or similar.

after losing the will to live
call kenlowe ask for a fan that has the equivilant power/performance
of a Viscous fan and await thier reply.

I'm with Tony (White90) on this one. A couple of years ago I ws thinking of fitting an electric fan to my V8 Discovery. I phoned them and asked them what was the best to fit. They told me to fit a pair of 18" fans but that they could not guarantee it keeping the engine as cool as the viscous fan, especially when offroading at lower speeds.

Dear Sir,

I'm not trying to get involved in the which is better debate but would like to understand the reasons for theses claims.

Offroading would be low speed so little forced cooling through the radiator and at relatively low engine rpm - so the viscous should be spinning towards the lower end of its rpm range hence drawing less air than the equivalent electric that run at one speed.

Yours, most puzzled,
O2.

Offroading means using low gears and so slow forward speed, but engine can be under high revs and high load, therefore generating a lot of heat.
Low forward speed = low natural air flow through rad (NOT talking about engine speed here).
Just because the landrover itself is going slowly, doesn't mean engine isn't working hard. You are right, in that if the engine is NOT revving hard, then the fixed/viscous fan may not shift as much air at low engine speeds as a fast electric fan which would be turning at the same speed/moving the same amount of air regardless of engine speed. All this is dependant on the comparison between the capability of the two types of fan to shift air though. A viscous fan MAY be able to shift more air with the coupling locked up when the engine is at 1500 rpm than the electric fan can at full speed, or it may not. Without knowing the fan performance, it is difficult to tell.

Regards,
Diff

Ignoring the which-is-better thread, I fitted an electric fan from famous four about 3 years ago.

The fan is made by Spal and looks the biz, their mounting kit is pretty good, though nothing you couldn't do yourself, and the thermostat is of a similar design to Si's, as far as I can see. Open to corection as I haven't seen the X-Eng one in the flesh.

The thermostat did die a month or 2 after I got it, but was replaced FOC.

If I was doing it again, I reckon I'd go the scrappy route, controlled by X-Eng.



oh, and Electric is better

a quote from Nas90 Dave which I still laugh at
"If you are using your 90 off-road or towing I personally would not use anything other than the viscous coupled fan. I have seen so many near misses with electric fan over-rides because "It's going through water" etc and then forgetting to turn the over-ride off and steam escaping from every orifice with engine temp gauges off the clock...............
The electric fans do not produce as much airflow as viscous coupled fans and for off-roading where you are using plenty of power but with very little forward speed electric fans are like pi**ing in the wind. I know this message will cause a wave of indignant replies from electric fan users, but their arguments have as much puff as their electric fans.
Trying to stop the fan to decide whether it is working correctly is a waste of time. If your temperature gauge is working accurately (check with a thermocouple on a multimeter) monitor the engine temperature under all conditions. If the temperature is within normal limits the fan is working!
You did not say what engine your 90 has.
Now wait for the replies...................... "

... but most of the time the engine would be running slowly otherwsie you would change down a gear rather than rev the b*lls off it surely? Once in a while you need to give some stick but that is the exception rather than the norm surely????? .... but still this noone has come up with an explanation to make me happy

Exactly.

I have found it very difficult to get figures for the amount of air (cfm) that various fans can shift, both electric and viscous, seems only Kenlowe/Pacet/et al publish figures. I've tried getting cfm figures for viscous fans or factory fit electric fans for various cars with no real success.

Arm waving and outlandish statements are all well and good but where the tech/figures to back it up?

All I can say for sure about my electric fan setup if they shift a lot of air (being electric they do this at any engine speed) and they 'seem' to shift more air than the viscous fan on my tdi, I reckon they are pulling over 2500cfm between them (2x12" fans), but it's very subjective and I can't really say for sure.

I'm not too keen on viscose fans (must remember to replace mine before France next week!) - they are not terribly reliable.

Electric fans have an advantage in terms of cost and controlability (and they are easy to bodge a replacement in an emergancy)

Although I'm still using viscose, I have installed the wiring harness for an electric 'just in case' fan.

I have read that an engine driven fan is capable of drawing 6hp from the engine a high speed. It would seem reasonable to assume you would need a 4.5kw electric fan to shift as much air.

However, engine fans are generally designed to run at low speeds and as the speed increases, the efficiency drops like a stone so it is possible that the fan spinning at 5000rpm is barely shifting more air than at 2000rpm.

One way or another, it seems that a typical 200w fan can shift sufficient air to provide the cooling you need. This is one of the major savings associated with going electric. The saving in power could easily be 5% of your engine output - most of which is being wasted as extra heat!

My Mag-clutch-fan should provide a best of both worlds solution to this - but it's still at the prototype stage (Mk3 being machined next week with a bit of luck!).

Si

Know of a lot of electric aeroplanes do you?

The Tdi viscous doesn't seem to do much simply because the engine doesn't produce much heat most of the time so it doesn't lock up. Leave my Discovery idling for a while after a long run on a hot day (4.0 V8 surrounded by lots of bonnet insulation and hot exhaust pipes) open the bonnet and blip the throttle to a couple of thousand revs and the viscous fan produces more wind than Hurricane Katrina! It only needs to run like this for about 10 sec and the rad is down to temp and it unlocks again. The vehicle also has electric fans fitted and when I had a faulty viscous unit they were running almost all the time to cope.

I'm not convinced about the power saving thing - if a viscous is unlocked it should be draining very little power (put the nut of the viscous unit in a vice and spin it till it unsticks, then it will spin fairly freely) and when you need cooling, directly using the mechanical energy to spin the fan must surely be more efficient than converting it to electrical energy and then back to mechanical again...? I am still running my Tdi without the viscous to try and persuade it to warm up quicker and it does seem to rev very slightly more freely when absolutely cold, but I don't know that there is much difference.