14 replies to this topic

[Hammer42]

Can anyone please confirm whether my fan is facing the wrong way. It was mentioned in a other thread that it may be but all the pictures I pull up show the fan facing the same way. Thanks ms in advance.

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[Spider]

Yeap, it's on back to front, but don't loose sleep over it, just change it next time your in there. They don't work as well as they could like this, but there's not loads of difference.

[Hammer42]

Ok thanks I'll change it over I have some time off and gives me an excuse to tinker. So what's the giveaway with the fan, the blade direction?

[hankins]

It has "engine side" stamped on it. Very easy to miss tho, as i have put mine on backwards in the past. 

[nicklouse]

the boss surface, the engine side marking is not on most current ones.

[nicklouse]

also if you read the info on say minispares they tell you

 

Genuine Rover part from BMH. 11 blade plastic fan, one of the most efficient fans ever fitted to a Mini. This fan pushes a lot of air with very little noise. If you need more air, then please see part# 2A998. This Hot Climate fan pushes even more air but it is substantially louder than the 11 blade version.

Make sure you fit the plastic blade the right way, the smoother moulded centre faces the engine, which might look wrong to some people, our picture shows the side that faces the radiator. If there is an F or word "front" stamped on it then that is the side that faces the radiator.

Minis from 1959-69 and 1990-1 had 12G1305 a thinner blade 1.100 wide at tips whereas this is 1.5"

 

[Hammer42]

Cheers everyone really appreciate all the help I've received from you all over the past couple of weeks.

[Cooperman]

I've not tried to measure it, but my understanding is that with the fan on the wrong way round the loss of cooling air flow is between 15% and 20%.

[Ethel]

Would it sap a bit more power back to front?

[Cooperman]

It would sap less power if on the wrong way round as it is shifting less mass of air. Actually the gain would be immeasurable in the real world as if driven to deliver the absolute maximum of power it would overheat. I guess it slightly reduces the rate of wear of the fan-belt   .

[Spider]

Ok thanks I'll change it over I have some time off and gives me an excuse to tinker. So what's the giveaway with the fan, the blade direction?

 

One quick way if you get muddled up with the plastic fans, if you look at the holes, they have an insert, one side is flanged, looks like a built in washer. The Washer goes under the bolt head

 

The new replacement fans, which I'm sure are not OEM, don't have the ENGINE SIDE marked.

[MrJenkinsEsq]

The easiest description I saw was that the blades should be cupped towards the radiator like this:

Engine ----(---- Radiator

Read this on a previous thread when I found I'd had my fan the wrong way around for the entire life of my 998 engine. Don't remember which thread it was to give credit to though, sorry!

[Ethel]

Each blade works like a little aeroplane wing. Instead of generating lift, it pulls the air in for the next blade to shove through the radiator. It still shoves air, like a flat blade would, if it's back to front - but the "wing" is flying backwards.

[Hammer42]

Job sorted thanks everyone! Turns out it did say engine side on the fan so I don't know how the previous owner mucked it up.

[tiger99]

Simple! The previous owner thought the radiator was the engine!

Actually there is a better explanation that does not insult his intelligence quite so much. It would go the way he had it on a Moggy, A30/35/40 or Spridget, to suck air through the radiator, with concave side facing the engine. But the subtle difference that the blades would be pitched in the wrong direction and would still try to blow air forwards if you did that with a Mini fan may have eluded him.

I am building a new PC with multiple fans right now. Some have to suck, others blow. It is not clear whether the most important one should suck or blow. I used to be a physicist. I fully understand why a normal person might be confused!

And what do you do if you have a standard A series gasket set and the cylinder gasket is marked FRONT? Fit it sideways? Same for many pistons...