MM fan blades

for those with Series MM sidevalve cars produced between September 1948 and February 1953

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Johnno
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MM fan blades

Postby Johnno » Tue Jun 12, 2018 7:47 am

Hi all,in view of my recent/past overheating problems,which way do the fan blades mount on the water pump?
Mine are mounted with the strenghtening struts facing the radiator,I think this is correct but am sure you lot can confirm or condemn!
Now checked EVERYTHING but cannot find any obvious problems.
Thanks guys.
Power to your Pistons,Johnnydoome.

alanworland
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Re: MM fan blades

Postby alanworland » Tue Jun 12, 2018 10:03 am

Is the impeller on the water pump still attached to the pump shaft? I know on some moderns they can detach although I think these are usually plastic.

Alan
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philthehill
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Re: MM fan blades

Postby philthehill » Tue Jun 12, 2018 11:47 am

The impellor on some AM water pumps are made from pressed steel and easily corrodes away.
Do you know what impellor is fitted to the pump?
The cast iron pump impellor is the best.

Below is a picture of a MM engine with fan blades fitted correctly.
coolant fan.jpg
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Johnno
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Re: MM fan blades

Postby Johnno » Tue Jun 12, 2018 2:01 pm

Still attached Alan.
Phil,my fan is much closer to the rad than that photo shows.Cast iron pump but blades seem shorter too.
Power to your Pistons,Johnnydoome.

philthehill
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Re: MM fan blades

Postby philthehill » Tue Jun 12, 2018 5:02 pm

Could you please post a photo of the fan/water pump pulley arrangement you have fitted to your MM.


Johnno
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Re: MM fan blades

Postby Johnno » Tue Jun 12, 2018 6:29 pm

Photos of fan/radiator.
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Power to your Pistons,Johnnydoome.

philthehill
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Re: MM fan blades

Postby philthehill » Tue Jun 12, 2018 8:12 pm

Thanks for posting the photos.
Comparing the photos with the workshop manual illustration the fan blades appear to be the wrong way round.
I would remove the fan blades and turn the blades through 180 degrees and see what effect it has on the running temp.


Johnno
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Re: MM fan blades

Postby Johnno » Tue Jun 12, 2018 8:16 pm

Yes,I thought the same thing but they are the same way as in your photo.
To be honest I have tried both ways and seen no difference in the over
heating problem!
Power to your Pistons,Johnnydoome.

philthehill
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Re: MM fan blades

Postby philthehill » Tue Jun 12, 2018 8:37 pm

The photo I posted above was primarily for the fan blade orientation and not the closeness to the radiator - also the cars radiator appears to have been removed so giving the impression of increased distance between fan and radiator.
With the type and style of radiator fitted to your MM I suspect that the blades could not be longer or they would hit the underside of the header tank.
I have looked again at the photo I posted and the two photos you have posted and the blades do appear to be fitted differently.
The defining feature in determining as to whether the blades are fitted the right way round is the taper on the actual blade and which should be at the leading edge of the blade rotational wise.
Is yours a one piece fan or two piece fan?
As you have tried the fan both ways and therefore (me) grasping at straws:-
If it is a two piece fan it could be that one blade is fitted correctly and the other fan blade fitted incorrectly so they are working against each other.
Whether there are other problems which cause the engine to run hot I do not know as you seem to have covered them all.
Firstly I would check that the leading edge taper of the fan blade is as it should be.
Phil


sirrom918
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Re: MM fan blades

Postby sirrom918 » Wed Jun 13, 2018 11:42 am

Viewing your second photo in its correct orientation, I'd say your blades are incorrectly fitted, they're not cutting into the air, pulling it through the radiator and over the engine. The red blades attached to the grey engine although non water pump fitted are I believe fitted correctly.

Something else to bear in mind, the two blades are apparently not identical - one is Blade Fan - Morris P/N X31437 and the other Blade Offset Fan - Morris P/N X31438 - perhaps both your blades are the same ?
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smithskids
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Re: MM fan blades

Postby smithskids » Mon Jun 18, 2018 8:07 pm

Don't forget the red fan blades on the dynamo are longer than the ones fitted to the water pump .


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