Spitfire Mark III Electric Cooling Fan

[johny]

Yes that figure was always suspect as its at max revs and on a dyno so no air being forced through by car movement.

At tickover a decent electric can flow a lot more air and, being closer to the rad, to greater effect. However I think really you only want an electric if you need more air flow at tickover or/and continued cooling after stopping the engine....

[Peter Truman]

Ref comments about keeping with the original mech fan or go electric I suppose it depends on where you live, here in Aus on a hot day OR in traffic the slow mech fan is inadequate and sitting in a traffic jam with foot on the throttle keeping the engine at around 1800rpm so the fan runs at higher revs to help cooling is a pita, where as the electric fan is fast and more efficient with more cfm output.

A few years ago we were in the Spit in a traffic jam for 45min on a peninsula freeway heading home from the beach on a 40C day, fortunately we were getting some shade from the gum trees along the roadside, but there was no way with just a mech fan we wouldn't have boiled but the electric fan (in those days hand on off only) controlled the car temp, but the gauge did get up to near hot, mind you we were bl***y hot too. I'm always envious of those in Merc's BMW's etc with their hoods down and air cons on full blast, seems odd but is the best of both worlds!

[cliff.b]

9 hours ago, johny said:

Yes that figure was always suspect as its at max revs and on a dyno so no air being forced through by car movement.

At tickover a decent electric can flow a lot more air and, being closer to the rad, to greater effect. However I think really you only want an electric if you need more air flow at tickover or/and continued cooling after stopping the engine....

That's the conclusion I have come to. What I am less certain about however, is the view that a fan isn't of benefit once on the move.

From my observations last year, the car did not actually overheat when driving without the mechanical fan but it definitely ran hotter. This was seen at the temp gauge and also the radiator return water temp which I can measure on the move by adjusting the thermostat until the electric fans cut in.

This is what I want to investigate further and if it confirms that the car runs hotter without the fan fitted, is this desirable? Personally, I would prefer it to run cooler but interested in any opinions on all of the above.

[johny]

Yes thats difficult to explain as the thinking is at more than a few mph the air forced through by the car movement is far more than any fan can do. So if you have overheating on the move the problem isnt fan related...

[Clive]

9 hours ago, Peter Truman said:

I'm always envious of those in Merc's BMW's etc with their hoods down and air cons on full blast, seems odd but is the best of both worlds!

in Sept 2019, a few months before the word changed, we had a holiday in California. Naturally we canted a convertible, choice was a golf or a mustang. 

The mustang it was, and despite it being disappointingly lumbersome and poorly built (though pretty quick) what was welcome discovery is it had cooled seats. As well as air con. Handy in Death Valley...

21 minutes ago, cliff.b said:

That's the conclusion I have come to. What I am less certain about however, is the view that a fan isn't of benefit once on the move.

From my observations last year, the car did not actually overheat when driving without the mechanical fan but it definitely ran hotter. This was seen at the temp gauge and also the radiator return water temp which I can measure on the move by adjusting the thermostat until the electric fans cut in.

This is what I want to investigate further and if it confirms that the car runs hotter without the fan fitted, is this desirable? Personally, I would prefer it to run cooler but interested in any opinions on all of the above.

People worry about temperatures. If it runs sometimes up to 100 degress, no problem. What is a concern is if the car gets hotter the faster you drive. That means the radiator is not good enough. No fans etc will help. Running too cool is a big problem too, the engine needs to be at about 80 degrees to keep the oil healthy. 

I had just that when I put a TR7 engine in my Toledo. I used a Polo radiator, same as I had used on my Zetec spitfire. It was OK at 40 mph, but at 60 the temp was getting higher and higher. Probably down to worse airfow that  teh spitfire. A £25 swap to a new passat radiator (30% larger) and problem solved. A fan should not be required over about 10mph.

[Chris A]

43 minutes ago, johny said:

Yes thats difficult to explain as the thinking is at more than a few mph the air forced through by the car movement is far more than any fan can do. So if you have overheating on the move the problem isnt fan related...

That confirms it then, in really hot weather I will drive even faster than usual to get more air flow through the radiator to cool the engine down and as a bonus more through my hair (if only) to keep me cooler.

"Mais oui Monsieur le Gendarme c’était impératif pour le bon fonctionnement du moteur " Do you think I'd get away with it . . 

[johny]

Worth a try especially if you can show him a temperature gauge in the red😂

[Pete Lewis]

well maybe if you go fast enough the mechanical fan will develop some horses not absorb them 

why dont electric cars have a ducted fan on the roof  ...self charging ???

the trouble with mechanical fans is they only lasted 50 years or so  keeping a good air flow under the bonnet not wait till its getting the carbs overheated 

and subsequent rich /low air content when in traffic   ...   keep the air flow 

and worry gauges have a big input into HOT   we have in the past had engines changed because of wrong temp senders

duff stabilisers , wonky gauges     duff rad caps   incorrect thermostats   and much more  ,    

engine temp is measured before the stat it is this that controls the coolant temp and flow rates  what happens after is all down to air flow , fans , radiators  and must haves 

 

Pete

[NonMember]

1 hour ago, johny said:

the thinking is at more than a few mph the air forced through by the car movement is far more than any fan can do.

That thinking is erroneous. The fan pulls really quite a lot of air - equivalent to rather more than "a few mph". Even when on the move, pulling air from behind the radiator encourages the "forced air" to actually go through rather than round. It makes a significant difference at anything up to open road speeds - say 50mph plus.

[cliff.b]

1 hour ago, clive said:

It is a concern is if the car gets hotter the faster you drive. That means the radiator is not good enough. No fans etc will help. Running too cool is a big problem too, the engine needs to be at about 80 degrees to keep the oil healthy.

My car temp gauge doesn't show any hotter the longer I drive, but it does if I drive hard and/or in very warm weather. But I would expect that.

Regarding oil temp, does any one have an oil temp gauge fitted? If so, what sort of temp is typical, does it vary much and is there a close correlation between oil and water temp? Wanting to understand if oil temp can rise significantly without much of a noticeable increase in coolant temp? 

 

[johny]

3 minutes ago, NonMember said:

That thinking is erroneous. The fan pulls really quite a lot of air - equivalent to rather more than "a few mph". Even when on the move, pulling air from behind the radiator encourages the "forced air" to actually go through rather than round. It makes a significant difference at anything up to open road speeds - say 50mph plus.

Difficult to prove one way or the other as Ive certainly never seen any test results. However my gut feeling is based on the mechanical fan not even being ducted plus the aero dynamics of my Vitesse is such that on the move air at the front has quite a bit of encouragement to go through the rad rather than round the body😁

[Pete Lewis]

the best part of having gauges telling you all sorts of clues is nobody has a clue what they really should tell you 

you know if you cane it at speed the oil is going to get hotter 

you know it will use more fuel  

why not fit a gauge to the gearbox and diff  they get so HOT you can fry eggs on them who worries about them (not the eggs)  

waste energy is dissipated by heat     and dont foget to check the temp of the charging system and wiper motor  they all get HOT 

time to stop the worry and get on with driving ...smile  

Pete

[Pete Lewis]

and ask Dave did they have electric fans on their Sahara trial  with the Heralds and Altas 

Pete

[cliff.b]

24 minutes ago, Pete Lewis said:

the best part of having gauges telling you all sorts of clues is nobody has a clue what they really should tell you 

you know if you cane it at speed the oil is going to get hotter 

you know it will use more fuel  

why not fit a gauge to the gearbox and diff  they get so HOT you can fry eggs on them who worries about them (not the eggs)  

waste energy is dissipated by heat     and dont foget to check the temp of the charging system and wiper motor  they all get HOT 

time to stop the worry and get on with driving ...smile  

Pete

Ha ha, despite how it might sound, this is mainly mild interest rather than paranoia 😱.

A few months ago I happened upon a US MG forum that was discussing why members were seeing 1500 engines lasting half as long (45000 miles) in a Midget compared to a Spitfire. The consensus seemed to be that this was due to the confined Midget engine bay and the effect on oil temp in warm climates. No idea if that makes any sense but got me thinking that, once up to running temp, the cooler the oil is the better, especially with the 1500 engine.

Consequently, if the mech fan does make things run cooler then it's worth having. Plus, as a bonus, I have electric fans if I should get stuck in traffic.

[Chris A]

27 minutes ago, johny said:

the aero dynamics of my Vitesse is such that on the move air at the front has quite a bit of encouragement to go through the rad rather than round the body😁

Once the air is under the bonnet it cares the hot air away from the rad and around the engine. Another reason for having a 13/60 rather than a vitesse :-

More room under the bonnet therefore more chance of the engine getting cooler . . .😁

[Pete Lewis]

my 1600 with unwrapped 631 and a few mods would idle for ages  if needed , (like MOT) never overheated or missed a beat 

cool oil is as bad as too hot oil   , triumph would have measured and recorded all these things in there testing and ended up with a workable solution to cover most car useage 

as i said  many  parts of the car get Soooo  Hot   and know one gives a fig .whats the obsessions with engines  ????

use branded coolant antifreeze and a decent engine oil and keep the transmission topped up and drive 

Pete

 

[Paul H]

Driving my Vitesse have no issues with heating issues . However in queues the gauge creeps up and one time queuing for 20 mins the gauge went to 115, the outside temp was in the mid 20’s c . For peace of mind if caught on motorways , dual carriageways etc considering a fan with a manual switch for these situations . Does a fan impede the airflow , effectiveness of the rad ? What size , make would suit . Your opinions appreciated . 
Paul

[Pete Lewis]

Paul do you have the multi blade plastic fan or the metal one ????

if swapped the old heavy metal for a plastic fan 

and did it get hot or was the voltage creeping up ??

Pete

[Paul H]

10 minutes ago, Pete Lewis said:

Paul do you have the multi blade plastic fan or the metal one ????

if swapped the old heavy metal for a plastic fan 

and did it get hot or was the voltage creeping up ??

Pete

Hi Pete . Plastic fan fitted . The temp gauge is not standard and think it’s called a thermo gauge and measures in degrees and “normal” is 80 to 90 . Came with the Vitesse and modern . 
Paul

[cliff.b]

31 minutes ago, Paul H said:

Hi Pete . Plastic fan fitted . The temp gauge is not standard and think it’s called a thermo gauge and measures in degrees and “normal” is 80 to 90 . Came with the Vitesse and modern . 
Paul

Last year, I changed the temp sensor for the 2nd time because the one that was supplied by a "reputable supplier" as correct for a Spitfire, wasn't.

Anyway, I decided to test the new, new one out and ran the car on the drive with the rad cap off until I could see coolant flow, assuming that the thermostat had just opened. 

Measured the coolant temp at 85C with Mrs Cliffs kitchen thermometer and the gauge was sitting a little below halfway, which is where it tends to sit most of the time now. 

So I would estimate halfway on my gauge is probably 90C which would appear to tie in with the readings you get from your mechanical gauge.

[johny]

The problem I have with a hot engine and why I worry about it more than hot gearboxes or diffs is that the idle goes and it becomes lumpy and unhappy...

[Pete Lewis]

if it goes lumpy when hot i would suggest weaken the mixture a little ???

Pete

[johny]

But mixture is spot on so I prefer to keep engine temp middle of gauge👍

[Iain T]

I like the control given with an electric fan. Sitting in a traffic jam in hot weather with only a crank driven fan and the temperature rising makes for an unhappy driver. As a boy I remember seeing many cars boiled up in summer, ok mainly due to poor maintenance but the piddly fans didn't help. 

[johny]

Yes before I changed my bearings and oil pump the tickover would go low and oil thin so that the pressure warning light started flickering😌 My brother had an old Alfa Romeo twin cam that actually had a knob on the dash for raising the tickover (separate from choke) under such conditions which I thought was a great idea...