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MG TD TF 1500 - Impeller design

The original water pump impeller was a pretty primitive piece of iron. Four straight vanes are used to push water through when spinning.

A more efficient design was created by moving from four vanes to six. However, they are still straight and primitively made (if the picture here is anything to go by).

I was wondering if anyone had considered a modern design with curved vanes (computer modelled)? There must be much more advanced impellers on the market of a similar size. Just curious if anyone had researched this.

Geoffrey M Baker

Here's a picture of a much more advanced impeller with curved blades and a rising profile...

Maybe one of you engineers out there might want to think about it...

Geoffrey M Baker

I seem to recall, could be wrong; that any more is less, as due to design of the system it just causes cavitation. It might be more interesting to go to an electic water pump.
mog

Not an engineer but speaking from actual practice, I think a 3 row core radiator in place of my original 2 row version made all the cooling difference in the Missouri hot, humid Summers. My TD pump is still factory stock.

Jim Merz

mog, that is true only in a general sense; there is always a point of no return in any system. However, 6 blades are now used with positive results, so increasing the number of blades by 50% did not hurt. Increasing to, say, 8 blades (but thinner, maybe?) would, I imagine, improve it still further. Also, a curved profile should move more water without increasing either cavitation or increasing the cubic area of the vane profile (the more vanes, the more water moved but also the more vanes the more volume of metal therefore less volume of water that can pass... at some point it becomes a trade-off)
As far as your radiator, Jim, I totally agree, it's another area that brings improved cooling. Electric fans can also do this.
Still, cost-wise, an improved impeller design would be much less expensive than a new radiator core, or even an electric fan (needing an upgraded generator or alternator)...
And finally, I'm not sold on electric pumps, because it's another disconnected system which might fail. The old bolt-on, driven by a belt system seems to me to be less problematic.
Just an interesting idea...
Geoffrey M Baker

Geoff,
The current system, if clean and looked after well seems to work just fine. The improved 6 blade impeller was a good idea and if you are replacing the water pump would be a sensible change (the Concourse police won’t see it either :))
I don’t think it is a good idea to try and fix a clogged or bunged up system by forcing more water through it instead of rectifying the problem.
This thermo-syphon with pump assist system has worked for me just fine for 45 years and apart from the nice 6 blade impeller fitted by Butch Taras to a water pump I have as a spare. It has caused me no issues [touch wood]
Not sure I would really want to through more money at it to be honest.
Unless you live in a really hot environment or drive in town traffic a lot. Possibly a bigger faster fan may be the better option.
JMTCW
Rod
R. D. Jones

Rod, the engine is in the shop being de-bunged right now :)
The only good side-effect of burning a cam bearing was that when I'm done, my engine will be running optimally... AND I'll know what all the problems are/were!
I'm leaning towards the six-vane impeller on a modernized pump (modern seals and bearings) because I need to rebuild the water pump and you can no longer buy the seals I need for a simple rebuild ... but while I'm at the stage of thinking about it, I like to try to consider every possible aspect of improvement...
Geoffrey M Baker

Here's a thread from the archives,,,,for water pump seals,

http://www2.mg-cars.org.uk/cgi-bin/gen5?runprog=mgbbs&access=&mode=archiveth&subject=8&subjectar=8&thread=2014100106141624454
SPW
Steve Wincze

My pump on the TF had an angled 6 vane impeller that I got and replaced sometime in the early 1970's, probably from Moss but could have been from Local MG Dealer. No idea of part no, brand etc.

But it has always worked well. Another mystery!!!
Don Harmer

Geoffrey,
I found the enclosed drawing somewhere in the net. I have no idea if Mr. Jaeger made a trial. May be someone here in the comunity can make a CNC model?
Cheers,
Guenter


GK Guenter

Hi Geoff,
When the seal I have posted arrives, you will see that they ARE actually available! I sent three to Gordon Clark following the archives thread Steve mentioned above. Thanks to John Walton in Sydney who found them but the identical seal here in South Australia has a different part number. The part number in South Australia is B03ABXS0127334.

Maybe I should start a new thread offering to send seals to whoever wants them.

Regarding the number of vanes on the impeller .... They work perfectly with the standard impeller. If you have a record breaker engine it might be an issue but with the usual supercharged engine I don't think it is an issue. I have attached an image of a supercharged TC race car (the silver thing at the front) which has a standard four vane impeller. No, it does not run alcohol which would help with cooling.

Bob Schapel



R L Schapel

I blew the core on my stock TF radiator many years ago and went to a dimpled core with an additional row core. Additionally, I changed the pump impeller to something else when it was rebuilt by someone a while ago to add the tapered shaft for the pulley). That works fantastic even in stop and go traffic here. In fact it works a little too well. I put in a modern t-stat with the little bleed valve last time and now it rarely makes full operating temp unless the temps are above 65 deg F. I put the bleeder valve t-stat in to avoid having to take the elbow off every time I needed to fill the coolant up after a drain. I'll probably Chang it back at some point to restore full operating temps. I'm not too concerned since I'm only running about 10-15c short according to the gauge.

To me... The stock system with a better radiator core is the way to go.

Alex
Alex Waugh

The radiator in a T-Series car is massive compared to the engine size. I don't understand why so many people have overheating issues. I have a standard core and a 6-blade impeller on a slightly built up engine. Even in 115+ degree heat through the Mojave Desert it has never had an issue.

I'm sure a modern impeller blade design could make some difference, but I'm not so sure it's worth the effort.

Steve Simmons

When I rebuilt/restored the 72 MGB, my son rebuilt the radiator with a larger core with more rows and improved the cooling immensely. I had him rebuild the TF radiator the same way, with an extra row of tubes. PJ
Paul S Jennings

This thread was discussed between 28/03/2015 and 05/04/2015

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