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Fan Orientation


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#1 phillrulz

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Posted 08 July 2019 - 05:43 PM

Right, guys theres a good thread on facebook over the correct orientation of a fan..

 

Everyone including myself reads the fan with the "engine side" imprint however....

 

 

Rover manual AND haynes show the fan reverse. Ones a picture ones a drawing.

 

So whats going on here 

 

 

EDIT - Me being stupid regardless of fan orientation, still blows with blades in same orientation however its either 1/2" deeper in cowl or not. 


Edited by phillrulz, 08 July 2019 - 05:58 PM.


#2 Rorf

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Posted 08 July 2019 - 05:57 PM

Search this forum, it will tell you which way to install the fan :D



#3 phillrulz

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Posted 08 July 2019 - 05:59 PM

Search this forum, it will tell you which way to install the fan :D

 

Ah i know was confused in a thread and forgot flipping the fan over doesnt change the blade orientation it only pushes it 1/2" closer to rad 



#4 MiniMadRacer

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Posted 09 July 2019 - 10:57 AM

My understanding is the "orientation", "which way around the fan goes", does matter.... air will flow if the fan is on the wrong way around but nothing like as efficient as having it on the correct way around.



#5 nicklouse

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Posted 09 July 2019 - 01:04 PM

Look at the fan profile. You will see that it is not the same. There is a leading edge which is what cuts into the air and the shape then maximizes the flow it can create. Fitting it the wrong way around still works but not as well as the thinner trailing edge is cutting into the air first and deflects more changing the blade profile reducing the air flow.

Smooth side to the engine.

#6 Cooperman

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Posted 09 July 2019 - 02:00 PM

As I understand it, if the fan is fitted the wrong way around, it will flow approximately 20% less cooling air.

 

However, I have even seen a 'works' rally car with a 4-blade fan fitted the wrong way by a factory team mechanic! So even the best can get it wrong.

 

If ever asked to look at a Mini which is overheating, the first thing to check is the orientation of the fan.



#7 Moke Spider

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Posted 09 July 2019 - 11:07 PM

As I understand it, if the fan is fitted the wrong way around, it will flow approximately 20% less cooling air.

 

However, I have even seen a 'works' rally car with a 4-blade fan fitted the wrong way by a factory team mechanic! So even the best can get it wrong.

 

If ever asked to look at a Mini which is overheating, the first thing to check is the orientation of the fan.

 

I've actually found it makes very little difference which way the fan goes, in regards to how much air is pushed.



#8 nicklouse

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Posted 10 July 2019 - 12:13 AM

As I understand it, if the fan is fitted the wrong way around, it will flow approximately 20% less cooling air.
 
However, I have even seen a 'works' rally car with a 4-blade fan fitted the wrong way by a factory team mechanic! So even the best can get it wrong.
 
If ever asked to look at a Mini which is overheating, the first thing to check is the orientation of the fan.

 
I've actually found it makes very little difference which way the fan goes, in regards to how much air is pushed.

Interestingly put. So I will read between the words and ask. What have you found?

#9 Moke Spider

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Posted 10 July 2019 - 12:45 AM

Nick, I've not made any CFM measurements, but just observations over the years.

 

When I had the business, probably 2 in 5 cars that came in had the fan around the wrong way. While I pointed this out to the customers, few had overheating issues and those that did, on swapping the fan around the right way, it made no difference. Their issues lay elsewhere.

 

Since, on finding them the wrong way around, I don't usually make a point of changing them unless I'm in that end of the engine anyway doing other stuff. I'm sure Air Flow suffers, but not to the point where it makes any difference if there's an overheating problem and this is the cure, I've always found, it;s something else.



#10 hhhh

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Posted 10 July 2019 - 01:47 AM

There is likely more power robbing with it fitted backwards.



#11 nicklouse

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Posted 10 July 2019 - 02:01 AM

Nick, I've not made any CFM measurements, but just observations over the years.
 
When I had the business, probably 2 in 5 cars that came in had the fan around the wrong way. While I pointed this out to the customers, few had overheating issues and those that did, on swapping the fan around the right way, it made no difference. Their issues lay elsewhere.
 
Since, on finding them the wrong way around, I don't usually make a point of changing them unless I'm in that end of the engine anyway doing other stuff. I'm sure Air Flow suffers, but not to the point where it makes any difference if there's an overheating problem and this is the cure, I've always found, it;s something else.

I agree on the over heating normally being something else.

#12 nicklouse

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Posted 10 July 2019 - 02:10 AM

I should add to this. The Midas that I am looking after. The owner was worried about over heating, and was thinking extra front fans ( front mount rad) and I said no worries it will be right.

Well it was a fresh engine build with a spotless block. Clean head and suitable stat. Fitted.

#13 Moke Spider

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Posted 10 July 2019 - 03:40 AM

There is likely more power robbing with it fitted backwards.

 

I actually wouldn't think so.

 

The amount of air any fan pushes is pretty much directly proportional to the Power put in to spinning it.



#14 hhhh

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Posted 10 July 2019 - 04:28 AM

There is a loss to sound energy which I think would be higher when fitted backwards. It gets complicated: https://www.research..._fig2_262535527


Edited by hhhh, 10 July 2019 - 04:31 AM.


#15 Magneto

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Posted 11 July 2019 - 01:36 AM

I found the fan on backwards on my 89 Racing Green Mini, so as I had to pull the water pump anyway due to a blown bypass hose I changed it around to the correct way. The car never ran hot before and it doesn't now, just like Moke Spider says - but boy howdy  is it noisy now!

 

The problem with HHHH's diagram is that the fan is NOT an air foil, it does not have that bottom flat chord.

 

I think the only reason the blades are curved is to make them stronger and less likely to flex under load - that said, the factory put the "engine side" identification on there for a reason I guess.


Edited by Magneto, 11 July 2019 - 01:38 AM.





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