WATER PUMP

[rgh0]

Photos of 4 impellors I have attached below of different materials - Aluminum, iron and plastic. I have collected these over the years and dont remember the original sources of the various types

Slight differences in details as I measured below


Height - The Aluminium one clearly designed to use a different seal height
Al - 13.0mm
Iron 1 - 21.0mm
Iron 2 - 21.3mm
Plastic - 22.5mm

Impellor fin height from back of impellor to top of outer edge of fin
Al - 9.5mm
Iron 1 - 11.0mm
Iron 2 - 11.0mm
Plastic - 10.5mm

Thickness of impellor from back to base of fin
Al - 2.5mm
Iron 1 - 2.3mm
Iron 2 - 2.0mm
Plastic - 3.0mm

The space from the face of the block to the cylinder bore outer casting is 14 mm plus or minus about a mm from measurement on a few blocks with the block wall thickness 3 to 4 mm. So provided the imellor inlet sealing ring is moved back a few mm and fitted into the block hole you could move the impellor back to unshroud the fins of the impellor.

A better design impellor, polishing the blades and sharpening the edges for better streamline flow would all also improve water pump flow. But in the end I dont think any is really needed versus the orginal design but moving the impellor forward and shrouding more of the blades with the block wall should be avoided.

Also included a photo of a couple of sealing rings one has only one O ring and no locating tab and is slightly thicker by about 1 mm but is made as a die casting like the orginal so not a home made item - dont know its orginal source.

regards
Rohan

[bcmc33]

Thanks for that, Rohan. This is a picture of the Burton impeller - as I said in the PM the vent outlet will be badly shrouded by the block.

I guess you can now understand why I was considering placing the impeller 6-7mm rearward.
I've ordered a pump kit from QED as their pictures look similar to what you've shown.

[bcmc33]

As a follow-up the QED impeller is more like the ones you have, Rohan.

I guess I need to make some changes before I run my new engine.

[SJ Lambert]

Anyone advise on where original spec pumps can be obtained in Victoria, Australia?

[rgh0]

The Elan Factory ( also known as Lotus Marques) has them. But Steve Taylor who runs the business has been ill so i dont know how responsive they have been recently to parts orders.

Service out of the US from Dave Bean or JAE is quick and reliable and with the Aust to USA dollar exchange rate where it is, they are probably the cheapest currently.

cheers
Rohan

[mark030358]

Hmmmm interesting photos on the pump impellers. I have fitted the Burton cassette with the Burton impellor. As I posted on another thread the engine looks like its running a tad cooler....

I think with the Burton one you wouldn't get the clearance in the timing cover. MAybe the one shown is for the cassette unit??

cheers

Mark

[el-saturn]

........................it'd be sooooooo easy IF we had all of the actual drawings on a site WITH cross sections, the important views etc... some of us can actually read drawings! sandy 36 4982

[rgh0]

Unfortunately it is not in the commercial suppliers interests to produce a detailed drawing of what they supply for 2 reasons. Dave Bean is one of the few companies that provide proper engineering details for many of their components when that is needed for proper selection and i will always give them credit for that.

The reasons most dont do it are:
1. Because it would enable poeple to copy what they supply more easily
2. Because it would enable people to compare what the various suppliers actually supply and determine more easily what will actually be a best replacement part.

So photos and partial reverse engineering on sites like this is the best you will get. Most of us don't have the time to buy up the range of parts from various suppliers and produce proper engineering drawings by reverse engineering them.

cheers
Rohan

[l10tus]

Part of the answer to correct water flow around the engine is determined by the size of the transfer ports in the alloy front casting.

The water flow produced by the impeller is forced through a hole (or port) in the front cover, then circulated around the engine.

So no matter what you do to the impeller, it won't have any major effect on the performance of the pump, due to this 'restriction'.

After speaking at length to the designer and manufacturer of the AKS removable water pump module, he informed me that was why he supplied a new front cover with a 10% increase in size of port or passageway in the cover, thus improving the water circulation.

I am led to believe that the AKS system gave the most favourable cooling through design, although the others apparently closely resemble it.

I have samples that may be referred to, if you need more info. Or can be of use in any way.

By the way, did you ever remove the radiator cap whilst your engine is running ?

It fairly gushes out with the flow provided by even the standard pump set-up - so not sure if you need to worry about improving the standard set-up ?.


Regards,

Phil.

[el-saturn]

..........with modern cnc mills you'd think there'd be folks out there who have made super intelligent and modern impellers for our TCs - i'll buy one! sandy - 4982