Fan Blade replacement

[geoberni]

We need a fan blade length audit! Anybody going to the National with a tape measure?

Stephen

Well I'm going, though not staying over as it's quite near home, so I shall be looking under every raised bonnet!

What I can say Berni is that my own 1098 in the car has a 12" blade and so do the 2x spare 1098 engines I have. That doesn't prove it but it would be rather odd if my 3x 1098 engines all had an unusual size of fan blade!

I wonder what length the metal fan blade is from a Mini? That would be a very bad move as a Mini fan blade is designed to push air rather than pull it!

Stephen

I believe the Mini Blade is 10", though the reverse pattern as you say.

[Bill_qaz]

We need a fan blade length audit! Anybody going to the National with a tape measure?

Stephen

Well I'm going, though not staying over as it's quite near home, so I shall be looking under every raised bonnet!

What I can say Berni is that my own 1098 in the car has a 12" blade and so do the 2x spare 1098 engines I have. That doesn't prove it but it would be rather odd if my 3x 1098 engines all had an unusual size of fan blade!

I wonder what length the metal fan blade is from a Mini? That would be a very bad move as a Mini fan blade is designed to push air rather than pull it!

Stephen

I believe the Mini Blade is 10", though the reverse pattern as you say.

Wasn't the mini a plastic multi-blade fan?
Although you could get a starting handle conversion

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[geoberni]

Wasn't the mini a plastic multi-blade fan?
Although you could get a starting handle conversion
Screenshot_20260429-161658_Chrome.jpg

As I understand it, looking at some Mini Forums etc, it went as follows:

1959–1961: Early cars had two or four-blade metal fans and pretty noisy. Pt No 2A997, 10", looked like the Minor Fan but opposite shaping.

1961–1970ish: A 16-blade metal fan (painted yellow) was used to reduce noise, about 10.5 " diameter.

1970 onward: The factory switched to pt 12G2129, a 11-blade aerodynamic plastic fan

[Bill_qaz]

Great be your fan knowledge Oberni one kenobi

Don't remember from mine

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[geoberni]

Great be your fan knowledge Oberni one kenobi

Just the depths I've been delving into this past few days, trying to understand what's occurring.... I don't like these sort of mysteries.
It all seemed simple a 10" blade unless a 1275 which had 12".
But I'm finding that more and more 'standard' Minors seem to have 12" fitted, with no owner knowledge of when it might have been changed.
Some of the cars have been owned for many decades

[Bill_qaz]

Don't know the provenance but my 1098 goldseal has a 12" fitted

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[svenedin]

I strongly suspect that 12" is standard for a 1098. My car was incredibly original when I first got it 37 years ago and I cannot see any reason why the fan blade would have been changed. I also had 2x 1098 engines cluttering up my garage until recently. I have both fans from those and they were also 12". One was old enough to have the non reinforcing rib timing chain cover which is an early 1098 and the other much later. I no longer have the engines as I gave them to a fellow club branch member but he's 92 and I anticipate getting the engines back in due course whether I want them or not......

Stephen

[philthehill]

I have only found two part numbers for Minor cooling fans (see my post above) and I have found no reference to the fitment of either 10" or 12" fan blades or at what point they were fitted. Has it been considered that both are right. Various parts of the Morris were made by different suppliers who made them to a general specification. For example the gearbox front cover was made by at least 3 different companies and all three are different but all comply with the general specifications. Also there may have been a shortage of fans - no just in time suppliers back then which meant that BMC had to use non standard fans from another model. Latterly BL were quick to use other parts to overcome manufacturing and supply difficulties for example blocks with liners when problems were found with the casting of the blocks.
Even if someone comes up with something definitive I would not be too worried as to what length fan is fitted so long as there is adequate clearance between the end of the fan and engine/cooling items i.e. hoses.

[svenedin]

I have only found two part numbers for Minor cooling fans (see my post above) and I have found no reference to the fitment of either 10" or 12" fan blades or at what point they were fitted. Has it been considered that both are right. Various parts of the Morris were made by different suppliers who made them to a general specification. For example the gearbox front cover was made by at least 3 different companies and all three are different but all comply with the general specifications. Also there may have been a shortage of fans - no just in time suppliers back then which meant that BMC had to use non standard fans from another model. Latterly BL were quick to use other parts to overcome manufacturing and supply difficulties for example blocks with liners when problems were found with the casting of the blocks.
Even if someone comes up with something definitive I would not be too worried as to what length fan is fitted so long as there is adequate clearance between the end of the fan and engine/cooling items i.e. hoses.

Berni, you're an ex-RAF engineer, Phil is ex-MoD too, I am MoD but not an engineer by any means. It is surely important whether the fan is 10" or 12"? The cubic inches the fan chucks out will be hugely different.

Stephen

[jagnut66]

Larger blade being prepped for yellow...

Hi Berni,
As an aside, up until 1958 (or 1959?) Morris Minor fan blades were painted Red when they left the factory......

Like many others on here, you've got me curious, I will measure mine tomorrow.
Best wishes,
Mike.

[philthehill]

The cubic inches drawn by the fan is inconsequential as once the vehicle is on the move the fan becomes irrelevant as the movement of the car pushes air through the radiator.
Only when stationary or at very slow speed does the fan become effective.
The Minor is vastly overcooled and can be run in many instances without a fan in these temperate climes.
As an aside driving the fan takes power which can be 4 bhp or more. One of the reasons I have a Vauxhall Corsa alloy radiator with a temperature controlled electric fan and a electronically controlled water pump.

[MikeNash]

Sirs,
It’s with considerable trepidation that I cross swords with m’Learned Friend Philthehill, but I cannot let his assertion pass, that “. . . the fan takes power which can be 4 bhp or more”. I suggest that for a two bladed fan of 12” diameter it’s about 1 bhp based on the argument that I’m sure he’ll remember that was discussed at length here viewtopic.php?p=364509&hilit=power+cons ... an#p364509

And if it helps regarding the fan diameter, the fan supplied to my parents that was fitted to a “Gold Seal” replacement motor in 1965/6 (and still running on my current engine) is 12 inches across.

Regards to all, MikeN.

[philthehill]

Mike
I was not part of the conversation which was pre 2011 & which was before I joined (2012) this web site discussion group so had no input to the thread.
The 4 bhp I quoted is a qualified guestimate.
Looking at the section on fans and cooling in Vizard's book 'Tuning the 'A' Series he does not give a specific bhp loss but states that "a fan of any size is going to absorb HP". All of the other books I have on the 'A' Series (and there are quite a few) do not give a specific bhp loss but all do state that the fan absorbs power and give ideas on how to reduce that power loss. I suspect that the non quotation of power loss is because of the variety of fans and water pumps fitted to the 'A' Series.
Phil

[Bill_qaz]

Different for tuned engine and racers such as Phil but on a standard Minor horsepower loss from the fan is irrelevant.
1 blade or 2

[myoldjalopy]

Yes, I can't see that it would make any appreciable difference......

[Mervin]

To complicate things a bit further. My car has a 1098cc Gold Seal engine and ribbed gearbox (Gold Seal). It was originally built with a 948cc engine.
The two blade cooling fan is 12" long.
Was that fitted to the 948cc engine and transferred to the 1098cc? Or was it fitted with a 10" long fan and a longer bladed fan used during the swap?
I don't know, it was before I owned the car. However, I think it more likely the 12" fan was transferred over. Why, because the genius who did the work transferred, probably the original, thin engine backplate, 948cc clutch and flywheel (now corrected)!

[les]

Different for tuned engine and racers such as Phil but on a standard Minor horsepower loss from the fan is irrelevant.
1 blade or 2

Agreed, we’re making a mountain out of a molehill ! Concerns about clearance maybe but loss of hp, forget it.

[geoberni]

To complicate things a bit further. My car has a 1098cc Gold Seal engine and ribbed gearbox (Gold Seal). It was originally built with a 948cc engine.
The two blade cooling fan is 12" long.
Was that fitted to the 948cc engine and transferred to the 1098cc? Or was it fitted with a 10" long fan and a longer bladed fan used during the swap?
I don't know, it was before I owned the car. However, I think it more likely the 12" fan was transferred over. Why, because the genius who did the work transferred, probably the original, thin engine backplate, 948cc clutch and flywheel (now corrected)!

I love that final comment.
When I got Basil, he has supposedly had his 803 swapped out for a 948 and the smooth gearbox had bee rebuilt with the 948 gears.
What I eventually found was that they had erroneously fitted a 1098 so he had the wrong backplate, which explained why the clutch required frequent adjusting. Some people eh...

But back to the fan length, I'm slowly reaching a conclusion, which I'll publish in the near future as it's a bit of a Sherlock Holmes deduction... "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."

[Bill_qaz]

I think we need to form a Berni fan club
The wearing of the club hat will of course be mandatory.
10" or 12" are both acceptable

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[geoberni]

I think we need to form a Berni fan club
The wearing of the club hat will of course be mandatory.
10" or 12" are both acceptable Screenshot_20260615-165735_Chrome.jpg

Sorry, only Red or Yellow will be permitted...