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[Jim G]

Hi everyone,
Looks like I now need to replace my water pump. I know BPNW and Moss sell uprated units for a bit more $. Does anyone have experience of them - are they worth the extra few bucks?

Thanks

[TR3driver]

I installed one on my TR3 last year, hoping it would help with my overheating problems.  I could not tell that it made any difference at all.  It has 6 vanes instead of 4, and they have a shape that is presumably more efficient; but they are also quite a bit smaller than the original vanes. 

So it probably depends on where you want to increase flow.  My uneducated guess is that the smaller vanes probably move less water at idle, but work better at high rpm (where the big square vanes have a tendency to cavitate).

There are some photos I took at http://s258.photobucket.com/albums/hh260/TR3driver/TR3-4%20Water%20Pumps/ of the new "high tech" pump, compared to an original pump (with the bright bronze impeller) and an aftermarket pump I bought from Moss maybe 20 years ago (cast iron impeller, I think, under the deposits).

[charley fitch]

I have been using the six vane pumps for a while now and on several cars.  The first units I bought from Ken Gillander as that was the only place I could find them at that time.  Since then I have bought units from Moss.  I like them, but like Randall I am not sure if they do that much better.  I do know that I was able to drive my TR3 up the freeway one day when it was 117 degrees without excess heating.  I am convinced that they help enough that I continue to outfit my cars (now Tr4's) with them.  Here is the bad part.  The last units that I ordered and received were from Moss and I note that the threaded end of the main shaft on the unit seems to be smaller than the older units. The main shaft must be the same size for the pulleys to fit. But the treaded end looks anemic.  I also noted that the thread is not conventional inch.  I suspect it might be metric, but so far I have not had to find a replacement nut for it.  I am just sure that it is not inch. I ruined one pump because the nut apparently came loose and the pulley wobbled on the shaft until it ate into the shaft.

Charley Fitch 

[TR3driver]

I do know that I was able to drive my TR3 up the freeway one day when it was 117 degrees without excess heating. 

FWIW, I've done the same thing with my TR3A, equipped with the aftermarket 4-vane in my photos.  But after an hour or so in that kind of heat, the passenger overheated, and we holed up in an air conditioned hotel room until it cooled off 

I've also had the stock pump in those photos up over 5000 rpm in my TR3 for 10-15 minutes with no signs of cavitation or overheating.  But I do run a 10 psi cap, so that might help with the cavitation problem.

[motomadness1947]

I just recently had MotorHead in VA rebuild my old pump.  They out source it but for the 90.00 or so that i cost it is like brand new.  Just an aside: I also had my radiator recored and today it was 96 in nashville and I never go the temp over 170 on the gauge.  I also installed and electric fan in front of the radiator for long stop lights or bridge back-ups but I have not had to turn it on yet.

Bruce Fahnestock