Electric Cooling Fans - Which One ?
Discussion
Very quiet 
I found this alternative to the Kenlowe.
http://www.revotec.com/acatalog/Jaguar-Tailormade-...
It seems to have a more robust mounting arrangement compared to the Kenlowe, but none of my classic car owning friends have used it.
I found this alternative to the Kenlowe.
http://www.revotec.com/acatalog/Jaguar-Tailormade-...
It seems to have a more robust mounting arrangement compared to the Kenlowe, but none of my classic car owning friends have used it.
do you have a cooling issue with the standard set up?
if you do an electric fan may not be the answer as a problem may lie elsewhere.
anyhow,...
there are advantages and pitfalls with them.
running carbs(I take it you are)can be prone to heat soak in traffic,hot weather etc and the engine fan is beneficial here in keeping the air moving around whereas an electric fan will only come on when the coolant reaches the required temperature and by then problems may have already started.
the advantages of an electric fan are IMO that; it will only come on when it is required so not wasting fuel like using the engine driven fan and it will give more cooling at idle/low speed when it is most needed.
but the electric fan has the downside in that the motor or control system could fail without warning and it could be too late before you realise any damage is done.
it's swings and roundabouts.
an every day car? I would keep the engine fan.but you could fit an electric one as well if there is room for that extra insurance if it is needed.
as to which one,most of them are good just fit the biggest you can and more importantly make sure you seal it to the rad and duct cold air from outside the car.any air gaps between rad and fan will result in hot air recirculation through the rad matrix and severely reduce the efficiency of the fan(I've seen fans mounted 6" from the rad with no ducting or shielding how inefficient is that?)
if you do an electric fan may not be the answer as a problem may lie elsewhere.
anyhow,...
there are advantages and pitfalls with them.
running carbs(I take it you are)can be prone to heat soak in traffic,hot weather etc and the engine fan is beneficial here in keeping the air moving around whereas an electric fan will only come on when the coolant reaches the required temperature and by then problems may have already started.
the advantages of an electric fan are IMO that; it will only come on when it is required so not wasting fuel like using the engine driven fan and it will give more cooling at idle/low speed when it is most needed.
but the electric fan has the downside in that the motor or control system could fail without warning and it could be too late before you realise any damage is done.
it's swings and roundabouts.
an every day car? I would keep the engine fan.but you could fit an electric one as well if there is room for that extra insurance if it is needed.
as to which one,most of them are good just fit the biggest you can and more importantly make sure you seal it to the rad and duct cold air from outside the car.any air gaps between rad and fan will result in hot air recirculation through the rad matrix and severely reduce the efficiency of the fan(I've seen fans mounted 6" from the rad with no ducting or shielding how inefficient is that?)
I bought an old Volvo pusher fan but never fitted it. I figured that if its good enough to cool a 2.0l Volvo 240 it would be good enough for my Sunbeam.
When I tested it it certainly shifted a lot of air, much more than the idling engine driven jobbie. The cooling system on the car was good, so I didn't bother in the end. Maybe if was using the car in heavy traffic and really hot weather I would have thought differently.
If you fit one and remove the engine fan it may be worth considering an over-ride switch.
When I tested it it certainly shifted a lot of air, much more than the idling engine driven jobbie. The cooling system on the car was good, so I didn't bother in the end. Maybe if was using the car in heavy traffic and really hot weather I would have thought differently.
If you fit one and remove the engine fan it may be worth considering an over-ride switch.
I prefer the mounting arrangement of the Revotec, the Kenlowe method is rather amateurish to me. Having said that I have used Kenlowe fans without problem.
As far as I know my Mk2 doesn't have an overheating issue (I've just got it) but I have found the older Jags to be marginal when sitting in slow or stationary traffic, especially if taken to France in the summer.
The limitation of the engine driven fan is that it delivers it's least performance at tickover revs which is the very time the car is most likely to overheat.
The electric fan can also be left on for a minute or two after the engine has stopped which prevents the dumping of water as heat soak takes effect.
As far as I know my Mk2 doesn't have an overheating issue (I've just got it) but I have found the older Jags to be marginal when sitting in slow or stationary traffic, especially if taken to France in the summer.
The limitation of the engine driven fan is that it delivers it's least performance at tickover revs which is the very time the car is most likely to overheat.
The electric fan can also be left on for a minute or two after the engine has stopped which prevents the dumping of water as heat soak takes effect.
I'm not sure which fan I have on the XK150, when I bought the car from RGC I asked for a an extra fan to be fitted since the minimal research I'd done back then suggested it was a good plan. The one they fitted wasn't the Kenlow one. Its down at Winspeed at the moment so I can't check. When CKL did the engine switch for me I had an oil cooler fitted, because I'd enjoyed a few track days. It made sense then to remove the mechanical fan so the oil cooler could sit where the normal fan swings.
I realise that it means I'm susceptible failure of the electrical fan, but mechanical ones are susceptible to fan belt failures. (see https://www.youtube.com/watch?v=4UPOVj3iWjo)
The electric one does stay running after the engine stops. XK engines are very inclined to overheating after they're switched off and it's amazing how far the temperature needle will go into the oil pressure gauge if you're careless. While the electric fan helps a little here it isn't the full answer. I find it works best as a reminder. Often the engine needs re-starting for about 20s a couple of minutes after switching off. By this time the fan has cooled the radiator and the water in there, but little convection has caused this to really flow through the block. A few seconds with the engine running and therefore the water pump running will bring everything down nicely. I've often thought of fitting an auxiliary electric water pump to better handle this situation.
The comment about heat soak and the carbs is another one I've suffered, and again the electric fan isn't necessarily the answer here either. It can be very effective at blowing the hot air from the radiator straight onto the carbs. I guess the Mk2 engine bay is much like the XK150's here, there isn't much airflow around the carbs so hot air tends to end up get trapped in that corner. Bonnet louvres were common, I guess for a reason. I believe it's common on the XK race cars for the bonnet mounting to be modified so the panel gap at the rear isn't quite what Sir William intended, leaving a nice space for the heat to get out.
Assuming my other problems have gone away, the issue of over heating the carbs clears as soon as I get to move at a reasonable speed. I had the fuel vaporisation issue on my last day at Goodwood the last time I went onto the track, after she'd hot sitting in the pit lane between runs. But in less than a lap it had cleared and she was running well.
Chris Window has suggested that if the vaporisation issue does become a real problem then it isn't too difficult to put something into the engine bay to deflect the airflow from the radiator away from the carbs.
I realise that it means I'm susceptible failure of the electrical fan, but mechanical ones are susceptible to fan belt failures. (see https://www.youtube.com/watch?v=4UPOVj3iWjo)
The electric one does stay running after the engine stops. XK engines are very inclined to overheating after they're switched off and it's amazing how far the temperature needle will go into the oil pressure gauge if you're careless. While the electric fan helps a little here it isn't the full answer. I find it works best as a reminder. Often the engine needs re-starting for about 20s a couple of minutes after switching off. By this time the fan has cooled the radiator and the water in there, but little convection has caused this to really flow through the block. A few seconds with the engine running and therefore the water pump running will bring everything down nicely. I've often thought of fitting an auxiliary electric water pump to better handle this situation.
The comment about heat soak and the carbs is another one I've suffered, and again the electric fan isn't necessarily the answer here either. It can be very effective at blowing the hot air from the radiator straight onto the carbs. I guess the Mk2 engine bay is much like the XK150's here, there isn't much airflow around the carbs so hot air tends to end up get trapped in that corner. Bonnet louvres were common, I guess for a reason. I believe it's common on the XK race cars for the bonnet mounting to be modified so the panel gap at the rear isn't quite what Sir William intended, leaving a nice space for the heat to get out.
Assuming my other problems have gone away, the issue of over heating the carbs clears as soon as I get to move at a reasonable speed. I had the fuel vaporisation issue on my last day at Goodwood the last time I went onto the track, after she'd hot sitting in the pit lane between runs. But in less than a lap it had cleared and she was running well.
Chris Window has suggested that if the vaporisation issue does become a real problem then it isn't too difficult to put something into the engine bay to deflect the airflow from the radiator away from the carbs.
caziques said:
Just remember, never have a fan on the front and on the back of the radiator. This disrupts the airflow and will make the problem worse.
My Merc has this as standard. Engine driven fan + 2 electric pushers on the front. The electric fans are primarily for the A/C but will will come on anyway, to help if things get too hot.mph said:
I prefer the mounting arrangement of the Revotec, the Kenlowe method is rather amateurish to me. Having said that I have used Kenlowe fans without problem.
As far as I know my Mk2 doesn't have an overheating issue (I've just got it) but I have found the older Jags to be marginal when sitting in slow or stationary traffic, especially if taken to France in the summer.
The limitation of the engine driven fan is that it delivers it's least performance at tickover revs which is the very time the car is most likely to overheat.
The electric fan can also be left on for a minute or two after the engine has stopped which prevents the dumping of water as heat soak takes effect.
Michael, you know your XK/XJ engines. For me, the very first port of call with an XK/XJ is to drain the coolant, remove all hoses and flush+reverse flush the radiator[ideally removed], the heater matrix and the engine until spotlessly clean and then refill the system with a good quality 50/50 home brew mix. The good old straight six always silts up at the rear unless really well looked after. Re' the engine fan, yes, remove this as soon as possible, replacing with an electronically driven unit + a manual override switch for the rare occasion it's driven in super hot weather.As far as I know my Mk2 doesn't have an overheating issue (I've just got it) but I have found the older Jags to be marginal when sitting in slow or stationary traffic, especially if taken to France in the summer.
The limitation of the engine driven fan is that it delivers it's least performance at tickover revs which is the very time the car is most likely to overheat.
The electric fan can also be left on for a minute or two after the engine has stopped which prevents the dumping of water as heat soak takes effect.
caziques said:
Just remember, never have a fan on the front and on the back of the radiator. This disrupts the airflow and will make the problem worse.
it shouldn't do.the radiator core will convert the air flow back to a laminar state so the fan behind the rad will see air as in normal driving conditions,if a car overheats in normal driving then as I said there is a problem elsewhere,an electric fan on the front will spin when it is not running while driving anyway so the masking of the radiator core is less than you would think.
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