Radiator fan

[Mrcoolabah1au]

Has any one tried out a thermic fan or clutch type fan blade just wondering weather they work suppose to save fuel or something like that

[T1 Terry]

So which are you thinking about, the electric thematic fan or the hydrostatic clutch fan? Finding a hydrostatic fan that would replace the fan you have at the moment could be difficult, the electric thematic fans require good sealing to the rad core and good area coverage, so a 13" or 15" unit would be required for your bus Wayne, will that fit your radiator core area?

[dcsingos]

When I used play with cars, we used to remove all fans and just run Thermatic fans for cooling as this helped to increase the horsepower on the Dyno. If you can get a large enough one to cover the majority of your radiator, otherwise get a dual fan unit, lots listed on Evilbay.

[Busman]

We removed the HUGE non clutched fan on VP that Davies Craig calculated was using between 10 and 16% of the horses, thats a huge amount and means if you were in the snowys in winter the thermostats would be jammed up tight trying to keep the detroit warm, but you would still be driving this HUGE fan !!!! Bloody crazy .
So we fitted 4 x 14" DC thermatics but put the 16" motors in them which gives them more grunt.
To ensure cooling on those really hot days we also added a Ford V8 radiator with 2 x 12 V fans which we ran in series (VP is 24V) and this radiator is isolated from the rest by a motorised ball valve.
3 seperate DC thermo switches/relays mounted in one of the return lines to the big radiator all adjustable.

We also moved the radiator 90 deg so it is now parallel with the long measurement of the coach, rather than across same (see radiators on website for clarification) We also made a grille to deflect air over the radiator, and make it easier to suck air in by the thermatics.
Test so far indicates working very well. Testing has only been done up to about 25 deg, at 100 kph on the Bruce Hwy.

I have 3 LED's connected that tell me which set of fans is working.
The top set in the big radiator is set lowest at about 80 deg (bit cool for a Detroit but a starting point), next the lower set, then the additional cooling.
So far we have only seen the top set come on, usually runs for a few mins then off for a similar period. The others have not come into play at all.
I did stop at one stage and, leaving motor running, adjusted the lower set on the big radiator so they came on. The upper set were running at the time and warm air was being pulled through them. When the lower set were running as well the air being pulled through them was ambient, or in other words the top set were doing such a good job they were removing all the heat in the top part of the radiator core.

I would not recommend this approach unless your prepared to do as we did :
Have radiator cleaned, not rely on being told it "was done a couple of years ago" or similar
Have block cleaned, after 3 different products we ended up using Restore which all the truckies use, cleaned it out as well as an acid bath
Position radiator for best air flow
Have the alternator to drive the fans (ours is 240 amps at 24 V) but of course we don't use that much.
Make shield that is air tight to fit thermatics to radiator.

For us it works, after we did the research, we have most of that 10-16% back in the form of fuel savings and power so pretty happy so far, we will see how the system performs on a really hot day towing the trailer with Vitara on board.

One thing I may consider is linking the house bank with the cranks and let the 2 Kw of solar run the fans, that way we would get all the energy back, but we will see how the present system works under extreme loads first.
Cheers
William

[SteveW]

The airtight shield is the thing - for a vehicle under heavy load.

[BruceS]

You wouldn't catch me doing it.
I guess a BIG engine doing virtually no work might get away with it. I'm sure the makers of the engines would have speculated electric fans if they thought they'd be an advantage.
Horton Fan would be the only one I'd use.
Just my opinion....
http://www.ngclark.com.au/products/hort ... clutch.htm

[Busman]

It was a Horton we tossed Bruce, bloody big and noisy and wasting sooo much HP.
The thermatics now are very efficient, when VP was built that was not the case.
Many vehicles now use thermatics as standard so i don't see an issue, as I stated we did our research and got the good result, if just strapping on a supercheap thermatic and expecting it to perform on an old glugged up radiator, then tears would be the result.

Cheers
William

[bagmaker]

+1
Thermo electric is the way to go
The radiator and cooling system is usually specified by the engine manufacturer. An ol' GM was designed prior to WW2 remember...........
Electric water pumps are also good value, Check out what is available at http://www.daviescraig.com.au/
Back in a previos life we experimented with hydraulic-driven cooling fans using the engine oil, bonus was cool engine oil.
A similar setup can be seen on some Caterpillar graders now days I believe.

Having stated that, i do recall a figure from Cummins (I think) that over 80% of engine failures relating to their make was due to cooling system failure of some sort.
An overheat alarm should be mandatory on any large engine.

[Busman]

Speaking to people who worked building these coaches you get the impression (strongly) that the mindset was over specify the cooling as the coach could be in the Snowy Mountains one week and Tennant Creek the next, they had no way of prediciting what was needed for ANY occasion so they covered all bases in spades, resulting in something that certainly seems more than necessary for a cooling system in good condition.

If you had too much cooling it was not a problem when it was cold, but certainly was when it was hot.

We have 2 alarm systems, light and buzzer as well as a working gauge of course with new sender unit. The over temp switches now days are set much higher, due to the increase in higher coolant pressure so the motor can run hotter to keep emissions down. Witness the bus fire near Nambour yesterday, is happening a lot in the US where the exhaust gas temperature is way higher than on a machine like VP

Cheers
William