Morris Minor Owners Club

Hi all,
Ordered a new water pump and the impeller is fitted to the shaft the wrong way round, so it turns ok but will not move any water, causing overheating.
Has anyone else had this issue? I'm mentioning this as I have just completed a couple of weekends work rebuilding the engine just to find an issue like this, and hopefully this will stop this happening to others. I will be 'chatting' to the supplier next week.

Welcome to the site - and hope things get better for you as time passes! Let us know the outcome please, just in case there is a batch of them that have been mis-assembled!

What makes you think that the impellor is the wrong way round?
In my experience the impellor of water pump cannot be fitted the wrong way round.
A photo of the pump and/or impellor would be appreciated.

Attached is a link to a water pump with the impellor fitted correctly.

http://www.minispares.com/product/Class ... ssic/water pump.aspx|Back to search[frame][/frame]

I too wonder how it can be wrong way round - picture please!!

Head pressure created by straight vanes impeller

Depend on this logic the head pressure created by the straight vane impeller is

H=\frac{U_2^2}{2g}+\frac{U_2^2-U_1^2}{2}



Shamlessly nicked from;
http://en.wikipedia.org/wiki/Centrifugal_pump

Exactly - just what I was thinking Marky.......

Perhaps he has one of the modern 'improved' pumps with a pressed steel impeller?

T

Until we get a picture..........

Hi,
Photo attached, the impeller is fitted securely etc, but in rotation it will not move water as efficiently as it would if spinning the other way. Tested in water out of the engine to prove theory of faulty pump. Fitted my old pump back (no photo, sorry) and problem solved. If anyone has any suggestions I would be grateful of your help. The work completed was a new unleaded head, servo, thermostat and housing, Duplex timing chain, and general fixing of some minor issues, the engine is now running quite well now after the initial fault of blown head gasket.
Cheers.[frame][/frame]

The impellor fitted to your water pump is fitted the correct way round! Also the vanes of the impellor are pointing in the right direction
All the pictures/illustrations/parts lists I have on file and the spare pumps I have all show or have the impellor as your photo.
Any water flow problems therefore must be caused by other means/sources/problems.
Have you the thermostat fitted or the thermostat blanking sleeve?

http://www.minispares.com/product/Class ... thermostat .aspx|Back to search

As the water pump in your picture has the large impellor do you have adequate clearance between the impellor and the coolant side of the cylinder wall?
See details in attached link below:-

Water flow is INTO the pump from the radiator via the bottom hose and the impellor vanes as per your pump pick up the water and throw it/push it out into the block and then via the thermostat housing OUT to the top hose and back to the radiator and back round again.

http://www.minispares.com/product/Class ... ssic/water pump.aspx|Back to search

The pump is exactly correct....nothing wrong with it.

Why had the head gasket blown ?? With the new gasket now fitted - you should retorque it to 44 ft lbf after the first heat cycle, and then reset the valve gaps.

as above ,but how did you manage to test it out of the engine

Can you post up a recording of your 'chat' with the supplier please ? This will be good.....

The impeller is fouling the engine, you have 2 choices, you can insert an additional gasket to pull the pump away form the engine slightly, .6mm to be exact or machine the impeller .6mm.
The perfectionist in you will want to machine the impeller, the perfectionists here will groan aloud if you fit another gasket, but .6mm aint gonna do any damage to the fan belt or engine.
Here come the perfectionists........................look out.

How do you know that the impellor is fouling the block?
As a perfectionist I would have made sure that I purchased a water pump with the correct length impellor so giving adequate clearance.

Looks like an A+ pump (I've recently fitted one) with longer impeller. Sure you ordered the correct one?

It is indeed the '1275' water pump - which will also be fine in 'most' 1098 engines... But the OP assured us it was turning - just not pumping water.... so that's not the problem...

Going right back to basics - is there a clear water passage through the pump for coolant to move through the inlet (bottom hose connection) to the impellor and out past the impellor to the block - if not there should be!
I have just examined a brand new and unused pump supplied by Mini Spares Pt No: GWP187/M273 http://www.minispares.com/product/Class ... .aspx|Back to search and the water passage on that pump is clear -absolutely no obstruction.
And yes the impellor is as the OPs picture.
There are no valves to block or come unstuck. There is a seal between the impellor and the pump body but that is unlikely to have disintegrated as coolant would leak past and appear out of the pump drain hole.
So has some thing been picked up by the pump and is trapped inside the pump body between the inlet and impellor? Has a piece of packaging or old hose pipe got trapped inside the pump blocking what should be a clear passage so restricting the water flow but still allowing the pump impellor to turn.
Shine a torch down the inlet pipe and see if the water passage is clear.
Is there excessive casting flash inside the inlet pipe so reducing the flow of water?
The inlet pipe does taper down towards the impellor.
Also check the clearance between the impellor and the pump body which should be 0.020" - 0.030". Excessive clearance will reduce the efficiency of the pump. If the clearance is excessive the impellor can be carefully pressed further onto the pump shaft to arrive at the correct clearance.
Check the internal bore of the bottom hose where the heater hose connects and see if the heater hose connection is partly blocking the bottom hose.
The coolant pump is of such a simple construction there is very little to go wrong.

( I thought it was sticking) would it if not sticking, be pertinent to measure against the size of the impeller on the old unit.
Of course it does beg the question if the old unit is good does it need replacing?