P38 Cooling & Kenlowe

I have a Kenlowe fan on my 4.6 P38 & the instructions say that the fan should cut in when the temp gauge is between 1/2 and 3/4. I have
noticed that when doing a steady 70ish on the motorway the temp gauge does start to climb up and the fan cuts in and drops the temp back down to 1/2 way or so.
Before I had the Kenlowe the gauge never moved over 1/2 and to be honest I don't really like it getting up towards 3/4 because we all know how sensitive the 4.6 & 4.0 are to overheating & slipped liners. Also, the engine book I have (How to Power Tune Rover V8 Engines for Road and Track) says that V8 should be run as cool as possible & that engines in P38s run extremely (too) hot for emissions purposes. Does bhp also drop as temperature increases?
I am surprised that the temp climbs so much at speed rather than at idle (in this weather it can idle without the fan cutting in), as I would have thought that sufficient cooling would have been provided by ram effect? The water pump is new & I removed & flushed the rad when I fitted the Kenlow. As I changed the pump and fan at the same time I can't be sure that the problem isn't something like water pump cavitation though. I am thinking of taking the Kenlowe off and replacing it with a new viscous coupling on my old fan to see what happens. IMHO I have found the Kenlowe to be a waste of time & the claims about MPG / performance increases are based on static fans (or those with seized viscous couplings), in fact I am concerened that the kenlowe is having a detrimental impact by having the engine running so hot.
Comments / suggestions?
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snipped-for-privacy@chrisallmark.com wrote:

If you want to really get into it, you should fit a "proper" temperature gauge of some sort - the car's gauge is not linear, and the difference between the top of the blue and the bottom of the red is only a few degrees. As it stands, it really only shows "Cold", "About right", "Getting Hot" and "Oh dear". Personaly, I wouldn't disagree about electic fans - you never know when they are not going to cut in........
Richard
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Yep, just about to start yet another engine rebuild for a customer, due to that fault (sorry, feature!).

Yes, max bhp is produced at around 78 degrees c.

Unlikely, these engines are actually very good "self-bleeders", they don't tend to suffer from airlocks or cavitation at all.

An excellent move, in my opinion. I despise electric fans, having seen too many fail and actually cause the same serious problems that they were fitted to allegedly prevent in the first place! A kenlowe type fan offers ZERO mpg savings over a correctly operating viscous coupled fan (think of energy losses to heat during the various conversions taking place!) and actually causes the engines temp to cycle between it's cut-in and cut-out temps, whereas the viscous simply "creeps" into action as the temp starts to rise, the result being a much more stable temp gauge! Anything that causes the temp to rise and fall continuously on an engine is BAD NEWS - think of thermal expansion and contraction across gasket faces and seals, I know it happens every cold start but once up to stable temp there's none of it at all; unless you fit a kenlowe type fan. Some vehicles, such as rear-engined hillrally type vehicles with high mounted radiators have no other option than to run electric fans, on those my personal preference is twin fans with one running permanently and temp control being left to the cooling system's thermostat, the second fan being there as a failsafe on an automatic "overtemp" switch. Any other front-engine/std radiator setup should use the std viscous fan wherever possible, bearing in mind it'll be inefficient unless the correct ducting/shrouding is reinstalled also. Badger.
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I have to agree with all this :-) If electric fans were so good I'm sure Land Rover would have started to fit them as standard. They don't (on any vehicle) - so something must be stopping them ;-) (and not just the bean counters)
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"Neil Brownlee" < snipped-for-privacy@pccontrolNOSPAMsystems.com> wrote in message
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On or around Tue, 23 Jan 2007 09:53:55 GMT, " banjo" <-

also, they can just fail anyway. it's very rare IME to have a viscous one fail "free", I've seen 'em that don't actually run free (in other words, they stay too solid), but that ain't going to kill your engine by overheating, just waste a bit of fuel and make a bit more noise.
Having said that I have a kenlowe on the transit - but that's 'cos some previous moron has sheared off the thread from the water pump that the viscous one should go on - since it's an unusual clockwise one I imagine they tried to "undo" it the wrong way.
the transit cools more than enough under all normal circumstances anyway - the kenlowe is there as a backup for when it's provoked into getting hot.
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In

As I recall "Normal" threads are clockwise "Abnormal" AKA LH threads are anticlockwise or as we say round here kackhanded. Or are you suggesting its an unusual clockwise thread cos its back to front?
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GbH wrote:
|| In ||||| I have to agree with all this :-) If electric fans were so good ||||| I'm sure Land Rover would have started to fit them as standard. ||||| They don't (on any vehicle) - so something must be stopping them ||||| ;-) (and not just the bean counters) ||||| ||||| |||| |||| water can burn out the motors when off roading through floods etc. ||| ||| also, they can just fail anyway. it's very rare IME to have a ||| viscous one fail "free", I've seen 'em that don't actually run free ||| (in other words, they stay too solid), but that ain't going to kill ||| your engine by overheating, just waste a bit of fuel and make a bit ||| more noise. ||| ||| Having said that I have a kenlowe on the transit - but that's 'cos ||| some previous moron has sheared off the thread from the water pump ||| that the viscous one should go on - since it's an unusual clockwise ||| one I imagine they tried to "undo" it the wrong way. || || As I recall "Normal" threads are clockwise "Abnormal" AKA LH threads || are anticlockwise or as we say round here kackhanded. || Or are you suggesting its an unusual clockwise thread cos its back to || front?
Yebbut, normal for a cooling fan is left handed, so a normal thread on a cooling fan would be abnormal elsewhere. Or is it, as the doctors write, Normal For Norfolk?
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In

Ah, I think, you learns somat new everyday!
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On or around Tue, 23 Jan 2007 15:23:48 GMT, "GbH"

most viscous fans are on LH threads, 'cos that way the engine tends to tighten them when it's turning. On the transit the fan is on something driven by the back side of the belt, so it goes the other way and it's a clockwise fan on a RH thread. This is the opposite of a normal viscous fan, and anyone expecting it to come undone like an LH thread will be disappointed.
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Serpentine V8 engines tighten the opposite way to a 300Tdi ... as does the TD5 engine (in fact the fans are interchangeable if you remove the cowling - just in case you ever need an emergency fan cos your own has shattered like mine did!). Can make it very amusing when a diesel owner tries to take off you fan, you let them argue with it for 20 mins, then saunter over and smack it the other way and wind it off ;-)
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In enlightened us thusly:

I'd've bin alright tho'!
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Thanks for the replies & especially for the very informative one from Badger. I hadn't thought of some of the points raised, particularly regarding expansion and contraction, so that's my mind made up. Just ordered a new viscous fan coupling & will remove the Kenlowe asap.
Cheers, Chris.
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snipped-for-privacy@chrisallmark.com wrote:

I too have been enjoying the chat.
I fitted a pair of Kenlowe's to my 1988 RRC in a fit of enthusiasm and have just removed them in case I wish to fit them to it's successor.
I noticed no change in fuel consumption etc in the 10 years of use. The only plus point was that it made belt access a doddle.
Odd point: the viscous fan seemed to warm as well as cool the engine. The temperature was rock steady once the engine was warmed - no change going up hill, down dale etc. Different story with the Kemlowe's fitted - upper temperature rose and fell slightly around the set point but on a long gentle motorway descent (e.g. anticlockwise on M25 from Reigate to M23) the temperature would drop to about 1/3 FSD.
Richard
FWIW the Kenlowe Hotstart on my first RR Classic, which was a very nasty TD conversion, was worth every penny.
R
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