Fitting electric fan to P6 Rover - few simple Qs?

M

montythemole

New Member
In a bid to use the Rover more, thinking of converting to electric fan from the current engine driven one. Also improves bhp and mpg!

Now I was planning to use a spare twin fan setup from a Mk1 MR2 that looked like it should fit and the two big fans would be sufficient, but sadly a little too wide. Radiator surface area 47x56cm.

Couple of quick Qs please as can't seem to find much help on the internet.

1) In terms of decommissioning the old fan, I just unbolt from the pulley and leave rest as is? It looks to me like the blades are bolted to steel or alu wide shaft, with the pulley then bolted to that. If I remove the fan blades only the shaft looks like it stays but is taking up a lot of room when I need to fit the electric fan?

2) Was planning on installing a variable controller with a capillary sensor a but like this in the top hose:
fancontrollerwhitewiresmaller.jpg


3) Where's the best place to get an electric feed from in the engine bay?

4) Anyone advise what size fan they run on a V8 in the UK? 10" or bigger?

5) Am I making this overly complicated and end result will look cack, so should I just buy a proper kit, in which case what is recommended?

Thanks for any assistance!
 
Just unbolt the fan.

I used the capillary type sensor but had trouble getting it to seal (most people don't - it may just be me :( ) so have got a Revotec one which fits into the top hose - like this one http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... K:MEWNX:IT

I use a 14" single pusher fan in front of the rad, I bought one of these - http://cgi.ebay.co.uk/14-SLIM-HIGH-PERF ... 1c1313b6a5 - because it was cheap and less than a mile from where I work.

I got the live feed direct from the back of the fuse box.

Richard
 
Thanks for response. So there's room in front of fan then? May see if the MR2 unit fits after all. If not the fan you recommend seems ideal.
 
I brought a Kenlow kit, they've changed the kit now so that the thermostat is poked throw the rad fins and not under a pipe. Not sure if the new way is any better but works fine. I made the mistake of getting a blow fan. I've changed it for a cheap suck 16" fan. Works a treat with the mechanical fan removed from the water pump.

New thermostat design.
 
Sorry if this is construed as hijacking the thread, but may I ask;
Richard, why did you regret using a blowing fan? Is it not a good idea to retain the pulley driven fan blade and augment it with a blowing fan on the outside of the radiator? (P6B, newly re-cored 2 row radiator, unfortunately when I had it done I didn't think of getting a third row fitted)
 
Thought i'd chime in here,
I bought my car with a kenlowe already fitted.
I always quietly had my suspicions about this, and after some investigation recently, it seems whoever wired it did so in reverse.
So its been shifting most of its air away from the rad, out of the front of the car :roll:
I'm not sure if the actual blades can be fitted the wrong way round too?...
 
I can sort of see the logic in that because it generally comes on when stationary in traffic and blowing
it out the front doesn't add to the under bonnet temperature and the problems that causes. What
would be a good thing is to have double pole switch to change the polarity and you can select which way
to blow depending on the circumstances.
 
On most Kenlowe fans the blades are reversible, ie you can set them up to suck or to blow. At least on the 10" ones you can't, though.

I've done a couple of posts on electric fans today that are probably worth collecting here:

I really don't see why anybody uses either of the cack handed ways Kenlowe use to control their fans. They send shudders down my spine as a mechanical engineer! The probe under the hose ought to be an obvious no-no. Why would you want to damage the longevity of your cooling system in so crass a manner? As for sticking a probe between the fins - Either it won't make contact with what its trying to measure, so you will only get an approximate idea of how hot things are.... Or it will be in hard contact with something delicate with inevitable consequences.....

There are three simple alternatives:

First. Use the sensor currently feeding your temperature gauge to double up feeding a small circuit to switch the fan relay.

Second. Fit the alternative thermostat elbow for the V8 which has a boss cast into it to accept a temperature sensor of the type used to feed your current temperature gauge. Use this to feed a small circuit to switch the fan relay.

Third. Get your radiator recored with a three row core and while you're at it get them to insert a standard rad fan switch from a modern car into the hot side collector tank. You don't even need a rad fan relay then!

Equipment for the first two options is widely available - Demon-Tweeks springs to mind. The third will not give any rad shop any problem at all.
Click to expand...

Tor asked whether a fan with curved blades was quieter than one with straight bades.

Some very simple maths answers this point. For a given rotational speed (rpm) of the fan, the speed through the air of the fan blade at any point along its length is proprtional to the square of its distance from the hub. Thus a fan blade that is quite happy halfway out from the hub could be supersonic by the time you reach its tip. Therefore you need to have a differnet attack angle for the blade by the time you get to the tip to the angle that is ideal close to the hub. Curving the blade helps to achieve this. For confirmation look at the propellors on a modern turbo-prop aircraft - the Airbus A400M military transport springs to mind - and you'll see exactly the same curved format for the blades.

There are two ways of looking at the effect. You can think of it as preventing the tips of the blades buffeting and creating noise, or you can think of it as allowing the inner parts of the blades to run fast enough to make a contribution to pulling the air through. So a curved blade fan will run quieter than a straight bladed one of the same size and it will also shift more air, so will keep the rad cooler.
Click to expand...

Chris
 
mrtask said:
Richard, why did you regret using a blowing fan?
Click to expand...

The main reason, I could see it throw the the grill, a little unsighley.
Also got one that was a bit too small, had to stay on all the time to be effective. The bigger one will run then turn off as it is able to cool the engine enough. Also makes less noise (posibley as its on the engine side of the rad).

Removing the fan made the engine quieter and feel (could be in my head) smoother.
 
Gents

I thought I'd bring this thread back into the forefront of peoples' minds as there has been a fair bit of discussion about the subject.

I've now completed the fit of my electric cooling fan. After several abortive attempts that all completely failed to keep the engine temp under control I bit the bullet and had the rad recored to 3 rows. Think I've now spent around £300 getting to the stage I'm at just now......which is not much better than when I started off with the engine driven fan :evil: :evil:

It's a long tale and I've had help and numerous discussions with a few people on here as I've gone. I'll skip the boring stuff and get to the crux of the issue.

With the new recored rad the temp of the engine sits nicely at 80-85 degrees whilst I'm driving along. The needle sits just over the 8 for the majority of the time as opposed to between the 8 and 5 in the previous set-up. So to my mind that indicates the cooling system is working well.

I have fitted a 14" on the front of the rad as a pusher because the thicker recored rad has reduced the clearance on the back of the rad, a point to note for all of you looking to go the 3 row core route. The fan allegedly pushes around 15-1600 cfm of air. When stationary, as the engine gets hotter the fan starts up as expected, but the airflow seems incapable of reducing the engine temp. It'll hold it at the temp where the fan came on but it does not drop. As soon as I start to move forward, increasing the airflow through the rad, the temp drops back to normal and the fan stops.

This all points to the fan not being able to shift a sufficient volume of air through the rad to cool the engine whilst stationary, yet others on here have 14 inch fans on their cars which do the job, so a fan that size on a 3 row cored rad should be enough.......only it isn't.... I would try a bigger, say 16", fan but that certainly wouldn't fit on the back of the rad and probably wouldn't fit on the front without further fettling to the valance. Smaller, twin, fans might be the answer but I can't find 2 smaller fans that say they will shift as much as the single 14" one I have :?

The other option I've seen spoken of here is a short nose water pump. The parts catalogue shows that the water pump designed to take the viscous fan coupling has a shorter nose. Is it possible to just change the pulley for one of this type or does the whole water pump need to be changed? If I don't see any improvement in performance or fuel consumption over the next few weeks I'll be fitting the engine driven fan again and running with both.

Cheers

Dave
 
Does it hold the temp for a long period IE in mock traffic type conditions? If so job sounds done to me :)
You only need the fan to be on when stationary and the temp comes up, as soon as you move you no longer require it so it's redundant again. Unlike the fixed fan which is working away all the time even when there's enough air coming through the front. Even if you don't notice, it will be saving you MPG and noise IMO :wink:
If the weather wasn't so hot you may see a reduction in temp too and the fan cut out again at stand still :D
 
Q1: Are the fan blades on the correct way round for pushing? Kenlowe are reversible and will blow whichever way they are on - but nowhere near as efficiently the wrong way.

Q2: What sort of fan is it? If Kenlowe I'd have thought that ought to be big enough - if not then you probably would need a 16". Kenlowe claim a much more effective blade design than others, which is born out by looking at the twisted profile of their blades vs others' straight blades.

Q3: What temp does the electric fan switch in at? It isn't going to pull the temp down to 85 unless you have manual control - it should cut out before then and then restart as it returns to its cut in temp. Also remember the gauge is showing the temp at the sender. The fan is controlling on the temp at a completely different place in the system, probably the rad. Unless you rev the engine to get the coolant circulating nice and fast these two temperatures could be very different at idle.

My plan - fans already in stock, - is a pair of Kenlowe 10" pushing from the front of the rad and controlled by a rad fan switch mounted in the rad hot tank. These supplemented by a Kenlowe 12" mounted offset at the back of the rad pulling and controlled by a manual pull switch in the dash.

Chris
 
GrimV8 said:
Does it hold the temp for a long period IE in mock traffic type conditions? If so job sounds done to me :)
You only need the fan to be on when stationary and the temp comes up, as soon as you move you no longer require it so it's redundant again. Unlike the fixed fan which is working away all the time even when there's enough air coming through the front. Even if you don't notice, it will be saving you MPG and noise IMO :wink:
If the weather wasn't so hot you may see a reduction in temp too and the fan cut out again at stand still :D
Click to expand...

Hi Grim

Yes the temp holds steady for as long as I'm stationary. Remember I'm about 500 miles further north than most of you and the temp is about 10 degrees cooler here :wink:

chrisyork said:
Q1: Are the fan blades on the correct way round for pushing? Kenlowe are reversible and will blow whichever way they are on - but nowhere near as efficiently the wrong way.
Click to expand...

Chris

Yes fan reconfigured to push.

chrisyork said:
Q2: What sort of fan is it? If Kenlowe I'd have thought that ought to be big enough - if not then you probably would need a 16". Kenlowe claim a much more effective blade design than others, which is born out by looking at the twisted profile of their blades vs others' straight blades.
Click to expand...

It's a race spec flat blade fan like the one quattro has.

chrisyork said:
Q3: What temp does the electric fan switch in at? It isn't going to pull the temp down to 85 unless you have manual control - it should cut out before then and then restart as it returns to its cut in temp. Also remember the gauge is showing the temp at the sender. The fan is controlling on the temp at a completely different place in the system, probably the rad. Unless you rev the engine to get the coolant circulating nice and fast these two temperatures could be very different at idle.
Click to expand...

Yes that's a fair point chris, fan cuts in just as the needle goes beyond the 5

chrisyork said:
My plan - fans already in stock, - is a pair of Kenlowe 10" pushing from the front of the rad and controlled by a rad fan switch mounted in the rad hot tank. These supplemented by a Kenlowe 12" mounted offset at the back of the rad pulling and controlled by a manual pull switch in the dash.
Click to expand...

Blimey! Can you get 2 x 10" fans in front of the rad between the rad and valance?

Dave
 
My experience from extensive experiments cooling very hot computers, is that one big fan is always better than several small fans (in the same area), the larger fans generally shift considerably more air at lower rpm and hence are much quieter than smaller fans screeming away.

To a certain extent this is dictated by the shape of the rad, if it's more or less square then the biggest single fan will be best, if it's rectangular then maybe 2 smaller fans will give more surface area coverage and hence better use of the rad.

Something i haven't seen discussed is the height of the fan on the rad, again assuming the rad isn't perfectly square, do you mount the fan nearest the top or the bottom ?
 
webmaster said:
Something i haven't seen discussed is the height of the fan on the rad, again assuming the rad isn't perfectly square, do you mount the fan nearest the top or the bottom ?
Click to expand...


Ideally the fan should be mounted as close to the inlet to the rad as possible so the hot coolant is immediately cooled, and then as it moves across the core it still has time to be further cooled in the normal way.
 
The two 10"" are intended to mount one at top right looking from the front and one at bottom left. This to get the central motors bosses so that one is behind the alloy grille proper (it's an S1) and one behind the central scoop in the undertray. I figured if I had a single big pusher fan the centre boss would line up on the depression in the undertray behind the bumper and duly foul. I too am nervous whether two 10" is adequate - the calculations say that with the Kenloew twisted blade design it should be - hence the manual reserve 12" sucker that will lie offset to top left looking from the front. That leaves a space at bottom left behind the rad to mount the engine oil cooler which will then get warmish air from the lower left side of the rad, hopefully obviating the need for an oil thermostat.

From these you will gather I have a very mixed view of Kenlowe. I think the fan design is excellent and well superior to other fan makes, probably worth one fan size. But their control system and fan fixing method are a full on catastrophe!

Chris
 
harveyp6 said:
webmaster said:
Something i haven't seen discussed is the height of the fan on the rad, again assuming the rad isn't perfectly square, do you mount the fan nearest the top or the bottom ?
Click to expand...


Ideally the fan should be mounted as close to the inlet to the rad as possible so the hot coolant is immediately cooled, and then as it moves across the core it still has time to be further cooled in the normal way.
Click to expand...


That's what I thought too Harvey, but without going into fluid thermodynamics (which I'm sure someone on here will know a good deal more about than us) I wouldn't have thought it mattered. If the purpose of the fan is to reduce the temp of the coolant by say 10 degrees (as an arbitrary figure) it'll do that whether it covers the rad at the inlet hose, middle of the rad or the outlet hose. That leaves the rest of the rad to do the remainder, but the net effect would be the same temp coolant exiting the rad?????

Unless the differential between the higher temp coolant entering the rad and the much lower temp cooling airflow at that point creates a much greater drop in temp eg 20 degrees (stay with me now :wink: ) than that at a point in the rad where the differential is lower and might only produce a 10 degree drop??????

During my abortive attempts with fans on my old rad I tried this theory out by fitting the fan at the inlet and then the outlet hose quarters of the rad and it made not a jot of difference to the cooling effect. But that might have been due to the inefficiency of my knackered old rad :D

I'll be travelling south to Luton and Uxbridge this weekend so will see how effective the cooling is at the higher average temps you've been having down there.

I do like chris's plan to cover as much of the rad surface area as possible with fans, but as Richard says, "the bigger the better"

Dave
 
One thing that's not been mentioned here is the engines ability to provide enough current at idle to spin the fan at the optimum speed. This could be why Dave3066 is seeing the temperature maintained rather than dropped.

My own car has a 13" Kenlowe HD two speed fan fitted. It has a 265W motor which starts off at 70% speed for a couple of minutes and increases to full speed if the temperature doesn't fall. However, there is a noticable increase in fan speed and curent draw (shown on the dash ammeter) as the engine speed increases to around 1200 rpm either by revving or driving away.

So, clearly the fan isn't pushing as much air through the rad at idle as the spec sheets would have us believe. Would a higher output alternator remedy this?
 
testrider said:
One thing that's not been mentioned here is the engines ability to provide enough current at idle to spin the fan at the optimum speed. This could be why Dave3066 is seeing the temperature maintained rather than dropped.

My own car has a 13" Kenlowe HD two speed fan fitted. It has a 265W motor which starts off at 70% speed for a couple of minutes and increases to full speed if the temperature doesn't fall. However, there is a noticable increase in fan speed and curent draw (shown on the dash ammeter) as the engine speed increases to around 1200 rpm either by revving or driving away.

So, clearly the fan isn't pushing as much air through the rad at idle as the spec sheets would have us believe. Would a higher output alternator remedy this?
Click to expand...

I think you're spot on there with that analysis.

I'm running a standard Lucas 11AC alternator and whilst the engine is idling it's probably not pushing out enough to spin the fan at full rpm. The fan is rated at 80W so compared to your mammoth 265W, which will be drawing about 20 amps :shock:, it's puny. I figured it would be enough though given that others use the same type on their car. I might have a quick look on the Kenlowe website for an alternative fan.......

Revving the engine on my car does result in a greater fan speed and corresponding current draw also.
 
Hi Dave, to be honest there wasn't much info on the Kenlowe site, it seems a bit out of date. I rang a fellow at Kenlowe called Jeff and he was most helpful. Whilst the fan was reasonably expensive I have peace of mind that I have the right part for the job without having to risk my engine with something from a scrap yard that may or may not work.
 
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