Water pump 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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Water pump fan blades.

Post by Johnno »

Hi all,is it correct that the fan blades are two different types? Speaking to a long term MM owner he seems to think the blades were not a ‘matched’ pair.If this is so,anyone got a pair they don’t need for sale? Still having overheating problems on my ‘52 with original engine.
Thank,John.
Power to your Pistons,Johnnydoome.
Murrayminor
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Re: Water pump fan blades.

Post by Murrayminor »

Is the remainder of the cooling system up to scratch?
Sometimes crud can build up or become loose causing partial blockages which can cause overheating.
The rad can also suffer from the same.
You can purchase radiator flush and you would be surprised what that stuff manages to dislodge.
A word of caution there are different camps who say flushes do not remove all of the crud and can cause issues, but I have used it a few times on older cars without issue.
Proud owner of my first Morris Minor
Johnno
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Re: Water pump fan blades.

Post by Johnno »

Ah thanks mate,done that’ a few times and seems pretty clear.Its been an ongoing problem for a while now. Don’t know what else to try.
Power to your Pistons,Johnnydoome.
Murrayminor
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Re: Water pump fan blades.

Post by Murrayminor »

Is the timing spot on? incorrect timing can have an effect on the engine which could cause overheating
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sirrom918
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Re: Water pump fan blades.

Post by sirrom918 »

The parts list shows that the two blades are indeed different:
Blade Fan - part number X31437 - illustration A80 - 1 required
Blade - Offset - Fan - part number X31438 - illustration A81 - 1 required

Also check that your blades are fitted the correct way round i.e. sucking air through the radiator not the other way round by using a smoke generator or some other means of producing smoke.
RobThomas
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Re: Water pump fan blades.

Post by RobThomas »

Only had single bladeson mine. Sure you've not got a bu66ered thermostat in there? Also, is the bottom metal casting blocked?
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smithskids
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Re: Water pump fan blades.

Post by smithskids »

We are talking side valve engine I presume? Mine same as Robs with 1 blade, never over heats even on a hot day doing 55mph or idling on slip road., Have you got a heater and is the heater valve open, even if you dont use the heater it helps the circulation at the back of the head.
Johnno
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Re: Water pump fan blades.

Post by Johnno »

Ok guys,a lot of info there. First off timing seems good as per road testing..single blade,hmmm sounds interesting but does that mean different water pump pulley? New thermostat but does not open until 100 is reached them immediately goes down to 80 but then creeps back up until boiling over.Heater valve open. I have a capillary type temp gauge fitting point taken from heater valve.Are the different numbered blades available anywhere?Yes,sidevalve engine.Thanks for your time and effort.
Power to your Pistons,Johnnydoome.
sirrom918
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Re: Water pump fan blades.

Post by sirrom918 »

A single fan blade was fitted to the late 1934 to 1948 Pre-Series / Series I / II and Series E Morris 8 side-valve engines. The BMC Morris Series MM Minor Service Parts List Fourth Edition seems to suggest that the two blades I mentioned in my earlier post - X31437 / X31438 were fitted to the early non-water pump Series MM side-valve engine.

On the later water pump fitted Series MM side-valve engine the two blades presumably changed their design in some way and were given new part numbers as shown below:

Blade Fan - part number X31662 - 1 required
Blade - Offset - Fan part number X31663 - 1 required

It would seem that the above two blades are the ones you need to be looking for.
RobThomas
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Re: Water pump fan blades.

Post by RobThomas »

Got any photos of what you've got fitted?
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philthehill
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Re: Water pump fan blades.

Post by philthehill »

If the thermostat does not open till it reaches 100 degrees then I would suspect that the thermostat is faulty or the wrong item.
I would be looking for the thermostat to open around the 75 - 80 degree mark.
The thermostat needs to be taken out of the housing, placed in a saucepan full of water - then gradually raise the water temp until the thermostat opens and at the moment the thermostat opens the water temp should be noted. A jam making thermometer is the type of thermometer to use.
To me until you know what the exact temperature the thermostat opens and closes everything is conjecture - I note that you have a capillary temperature gauge fitted which there again may be reading wrong.
You could always check the capillary temperature gauge against the jam thermometer by putting the capillary sender in the sauce pan of water and see how they compare.

sirrom918
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Re: Water pump fan blades.

Post by sirrom918 »

Rob,

I've a 918cc Morris 8 Series I Tourer rather than a Series MM Minor though I do have a Military Tank engine which as I'm sure you'll know was built around the late MM Minor water pump / external oil filter fitted side-valve engine block. None of these images are mine, I've merely found them on the internet / ebay over the years and kept them as a source of information, so can't say for absolute certain that the blades shown are correct. I would go as far as to say the blades on photos 1 and 3 look to me to be the correct style for the late engine. I'm not so sure about the blades attached to the water pump in photo 2 - they could either be the earlier non-water pump blades or could even be two Morris 8 blades joined together.
MM - Engine Table 2.png
MM - Engine Table 2.png (1.2 MiB) Viewed 2623 times
MM - Water Pump 2.png
MM - Water Pump 2.png (1.55 MiB) Viewed 2623 times
Screen Shot 2017-04-25 at 02.58.31.png
Screen Shot 2017-04-25 at 02.58.31.png (1.09 MiB) Viewed 2623 times
Last edited by sirrom918 on Fri Jul 12, 2019 6:57 pm, edited 1 time in total.
philthehill
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Re: Water pump fan blades.

Post by philthehill »

Here is another picture to add to the collection:-
coolant fan.jpg
coolant fan.jpg (90.88 KiB) Viewed 2620 times

RobThomas
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Re: Water pump fan blades.

Post by RobThomas »

I once went to fix an MGB. Owner had fitted a fan that pushed instead of pulled. Sure you haven't got the same?
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Johnno
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Re: Water pump fan blades.

Post by Johnno »

Well blades appear to be the correct way round.I have no photos of the fitment but is the same as philthehill’s photo.I will check the thermostat opening temp but is boiling water an accurate check?Does it not need pressure as well?
Power to your Pistons,Johnnydoome.
philthehill
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Re: Water pump fan blades.

Post by philthehill »

Having the thermostat in water that has the temperatures increased is a very accurate way of checking the operation and opening temperature of the thermostat. It is just replicates what happens in the cooling system.

No pressure is required when checking the thermostat opening temperature.

Johnno
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Re: Water pump fan blades.

Post by Johnno »

Ok,bit of progress.Just removed the dynamo/water jacket.Full of congealed anti freeze! It’s a new one from ESM three years ago.Never seen this before,what would cause the a/f to congeal like this?Not checked the thermostat yet Phil.
Power to your Pistons,Johnnydoome.
philthehill
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Re: Water pump fan blades.

Post by philthehill »

What antifreeze have you been using?

Johnno
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Re: Water pump fan blades.

Post by Johnno »

No idea really Ethylene glycol but dont recall the maker.Never seen this before.
Power to your Pistons,Johnnydoome.
philthehill
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Re: Water pump fan blades.

Post by philthehill »

It does happen and it has been reported on this forum before.

I would recommend that you use a Glycol based antifreeze after flushing the cooling system.

Phil

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