14 replies to this topic

[mk=john]

Hello
I have a 998 Mk1 Cooper. Yesterday I removed the water pump in order to refit a bypass hose (a good Kevlar one). Anyway, when I had the water pump off The shaft turned smoothly, no grinding or anything like that, just a little turning resistance but it turned very smoothly off the car.

Today, when I refitted the water pump, I turned it by hand and I could feel and hear a very slight scraping sound. It seems the impeller is touching the inside of the block, but I can't be sure. It must have been like this all the time.

Has anyone experienced this, and is it a common problem. If so, do I need a new pump, or can I fix this one? Any help will be greatly appreciated!

[Big_Adam]

Yep,

In the Vizard books he mentions that the cast steel pump when changed to a large bore pump made of alloy can foul on the block.

So you can either grind the pump or grind the block a bit.

[charminbear]

or put a couple of extra gaskets on!
If it is only just touching then the extra mm of a gasket should stop it...

[mk=john]

Hi
What do you mean by vizard book? The impeller on my pump is a pressed steel type. Is it possible the impeller has slid along the shaft? There is a gap of around 3mm or so metween the impeller blade and the pump body. is this normal? if not, can I alter the position of the impeller along the shaft?

Thanks

[Dan]

Did you use a genuine gasket and the water pump dowels?

[mk=john]

Hi
The locating dowels are in place in the block, two of them that locate in the pump body. The gasket is the thin type from minispares, red on one side, and black on the other.

Is is possible the impeller is not far enough along its shaft?. It is just scraping very slighly as I turn it. Can I just leave this, or shoud i now remove the pump?

Thanks

[Big_Adam]

Hey John,

Only just realised your using your old pump (though you replaced it). So...errm....I'm out of ideas.

As for Vizard, I mean David Vizard's tuning book.

[mk=john]

Hi
I have been researching the type of pump I currently have, and it is an aftermarket type with the pressed steel impeller, not a cast one.

I have been looking on the MiniSpares Website, and came across this Pump. The impeller sticks out from the body much less, and certainly wouldn't be anywhere near the block when it is installed. It is the standard (low??) capacity pump. Even though out of stock, is this pump sufficient for my engine? I have a 998 Cooper engine.

How do I know what pump to choose?

http://www.minispare....aspx?pid=34753

[dklawson]

John, if you decide to replace the pump for any reason, go ahead and invest in the high-flow pump from MiniSpares (GWP134). You'll have to modify the impeller a bit for clearance on an early small bore but in the end you'll have better cooling for it. It has higher flow for less money.

[mk=john]

Hi
I will now get the GWP134 High flow water pump. When you say modifythe impellor, do you mean remove material from it? If so, how much....is it just a case of adding a chamfer to it on the outside outer edge of the impellor?
I dont have access to a lathe, do I just grind it away until I get a clearance?

Thanks

[dklawson]

I have not had to modify the pump as I've only worked on 1275s. It's my understanding that the OD of the impeller at its deepest point fouls the block casting where #1 cylinder is. I've been told that the remedy is to grind away the impeller just enough to gain the necessary clearance. I suppose you could instead remove a slice of material from the block. However, it's a lot less painful to replace a pump if you make a mistake.

[mk=john]

Hi
I will consider buying the GWP134 High Capacity pump, if I knew that I needed only a small modification the the cast impeller so it doesn't foul the cylinder block. However, I have found the GWP132 Standard Capacity (with smaller imeller) for £8 new. Would this pump be OK to fit to my early 998cc Cooper engine? I never take the thing above 70mph, usually 60-65mph going to shows etc.

Thanks

[Ethel]

I'd guess so - it will turn faster with a small bore pulley anyway.

[mk=john]

Cheers Ethel

I know the GWP132 small bore pump is the waterpump that fits cars like an MG Midget. It should be a standard fit on my mini. The Somerford Mini website PDF file on water pumps does actually say that the GWP132 is a direct replacement for early engines.

[mk=john]

Hi
This weeked I want to replace the water pump, and picked up two pumps, one is the GWP132 (small impeller) and the GWP (large impeller). My engine is an early (1966) 998 Cooper engine running with a small diameter (3.875") fan pulley, and using a standard 3-core radiator.

My dilema is this: If I use the GWP134 large impeller pump, then will this force water down through the radiator too quiclky before it has had a chance to cool sufficiently?

I have tested the fit of the large impellor pump on my engine, and the impellot seems just slightly too long. Should I remove the flange of the impellor as shown in the following pic?

Or can and should I just stick with the small bore pump? I just want to get this right

Thanks

Edited by mk=john, 28 September 2007 - 11:58 AM.