SWB

Eight blade fan or four?.........

18 posts in this topic

Been given a military 8 bladed fan and all the pulleys.

Will 8 blades give more cooling than the standard 4?.

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Yes , but spec'd for the FFR I think , where they would be run on the hand throttle in high ambient temps . For ordinary use it should not be necessary and will suck up HP .

A std. set up with all the rad cowling should work very well

Steve b

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Standard will be fine! More than fine...

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Many thanks for your replies, Steve, what's HP?, excuse my ignorance.

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From my days "in" and sepia tinted memory. All Green fleet Land Rovers had 8 blade fans. You could hear them coming from a distance because of the roar from the fan

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Unless you have the radiator cowl on I would remove the fan altogether and fit an electric fan in front of the rad.  The unprotected belt driven fan has a habit of attacking peoples fingers.

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On 10/04/2017 at 2:15 PM, Romahomepete said:

Unless you have the radiator cowl on I would remove the fan altogether and fit an electric fan in front of the rad.  The unprotected belt driven fan has a habit of attacking peoples fingers.

Engine driven fans are superior to electric, but they do depend on the cowl being fitted, otherwise you just stir a torus of air behind the rad instead of drawing air through it.

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Thanks for the info, was hoping that fitting an eight bladed set up would alleviate fuel evaporation.

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On 4/13/2017 at 3:18 PM, Snagger said:

Engine driven fans are superior to electric,

Despite being a previous seller of electric fan kits - I completely agree with this!

A direct driven or viscose (preferred) fan can draw the equivalent of 10Hp (7.5kW) from the engine.  Compare that to even the most powerful electric fans at 2/3Hp / 500W and you see why an engine driven fan will provide way more cooling.

There is an argument that in cooler places like the UK you don't need that much cooling - until you do!

Si 

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8 hours ago, SWB said:

Thanks for the info, was hoping that fitting an eight bladed set up would alleviate fuel evaporation.

It may well help with this, but you should try be getting fuel evaporation on a standard 2.25...

What's your fuel pump, carb and exhaust set up?

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1 hour ago, simonr said:

Despite being a previous seller of electric fan kits - I completely agree with this!

A direct driven or viscose (preferred) fan can draw the equivalent of 10Hp (7.5kW) from the engine.  Compare that to even the most powerful electric fans at 2/3Hp / 500W and you see why an engine driven fan will provide way more cooling.

There is an argument that in cooler places like the UK you don't need that much cooling - until you do!

Si 

I remember Pete telling me on an Atlas Overland tour about a 90 that kept overheating on a Moroccan trip.  It turned out that the owner had remove the fan, with no electric replacement, on internet advice, and was insistent that "Tdis don't need fans"! :blink:

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9 hours ago, SWB said:

Thanks for the info, was hoping that fitting an eight bladed set up would alleviate fuel evaporation.

The four bladed fan should be ample.  The eight bladed fan was for prolonged idling, where low engine rpm didn't draw enough airflow.  That is why it was generally only used on vehicles that powered electrical equipment, like MoD FFRs, or farm machinery.   However, many Series vehicles are missing the cowl that attaches to the rad because of owners and bad garages botching a rad replacement (too lazy to fit the screws, or too lazy to replace lost or damaged screws).  Without the cowl, the fan just stirs the air behind the rad, in a torus (doughnut) around the ends of the blades instead of drawing cool air in through the rad and passing out the back of the fan over the engine and manifolds.  So, if your cowl is missing, that's the problem.

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Been there, done all that, and an 8-blade fan is too much. I've got one and it doesn't help with the power from that poor little motor. A good quality electric fan would be far better. I've had plenty of trouble with fuel vapourising. It shouldn't happen in a mild climate. In a hot climate like where I live, I would be inclined to put in a return system like the V8 has with an electric pump, but that's extreme for anywhere else. (Of course I haven't actually managed to get around to doing it yet!) 

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On ‎22‎/‎04‎/‎2017 at 8:10 AM, Bowie69 said:

What's your fuel pump, carb and exhaust set up?

2.25 petrol engine, mechanical fuel pump, Weber carb with a stainless steel exhaust system.

Fan cowl bought early last year and fitted. Fuel evaporation occurs when been out for a run and parked up, will start and drive for 100 yards, then it's bonnet up and manually pump fuel pump, (new unit fitted, still the same as the old one).

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Is there any form of insulator block between the carb and manifold ? Also , when it stops as you describe how many pumps on the prime lever to get it going ?  What happens if you leave it ticking over upon re-start after a run ?

cheers

 

Steve b

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I'm unsure why there would be enough heat to vaporise fuel at the pump or before, does the fuel line follow a normal route?

Is there potentially damage to the line (pinhole) before the pump meaning it has a hard time when hot pumping fuel?

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Are you sure you don't have a pin hole leak like Bowie describes, or failed check-valves allowing the fuel to drain back to the tank when the engine is off and making the lift pump weak when running?  I'd take a close look at the fuel filter for leaks.  The symptoms are very similar to those I and others have experienced with diesels when an air leak allows air into the system.

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