water pump differences

[dyeager535]

I know this gets discussed fairly regularly, but I ran across a page that illustrates a couple of potential differences in water pumps.

Water pump pics

As you can tell by the link, those are Oldsmobile pumps, but nonetheless, same idea as Chev.

Here's a GMB pump with the tack welded plate visible. Notice the impeller blades are further from the housing in that application though.

Pretty easy to tell with Olds, since there is no back cover/gasket. I've been thinking based on what I've seen in the above links that it would be beneficial to check your new waterpump design. I have no problem with cooling, but it's pretty obvious the larger impeller alone is going to work better, and would be something to consider for those that want additional cooling capability.

 

[pauly383]

What would be nice is if the Chevy ones come with that plate welded on .

I need one for the Chevelle before I'm done , and it would be nice not to have buy the 5.99 kit from jegs and drill holes and do it yourself .

 

[dyeager535]

Well the problem on the Chev's is just that you can't see it!

I know that company's like Stewart's have pumps that are claimed to flow better (not doubting, just not a customer) and I wouldn't doubt the impellers are different.

There very well could be pumps out there commonly available that are designed like this (AC applications, etc) but without pulling the cover, you'd never know. If you pull a bad waterpump, you could always check it of course.

 

[ntsqd]

I put a Stewart pump on a 302 Ford. B4 I did that I had an engine that warmed up fairly fast and would overheat when worked hard. I had done every thing BUT replace what was supposed to be a good and recently installed H2O pump.

Nothing I did made much difference.

Putting on the Stewart pump cured the over heat problem. It also meant that in the winter I had to use a piece of cardboard in front of part of the radiator when not towing just to get the heater to work (on the CA coast!).

When the time comes I won't hesitate to put a Stewart pump on my next tow rig.

 

[dyeager535]

That really proves what they've been saying all along, that you can't move coolant "too fast" through the system.

I don't want to start an argument with anyone here about it, if you don't believe the above statement, head over to stewart components(?) website and read about it, because their info is what I believe.

 

[CyberSniper]

The faster you move the water the more energy you lose to moving that water... the more horsepower lost to heating up that water.

As long as you have a fast-reacting thermostat then you can't flow the water too fast. If you have a junk thermostat that can't shut off high flow rates of water very well or if it is slow to react then you'll run into problems (like an instable water temperature).

Thermostats today, even the cheap ones, are better than the ones from the 70s.

 

[dyeager535]

The faster you move the water the more energy you lose to moving that water... the more horsepower lost to heating up that water.

Exactly why higher *efficiency* from the existing design makes so much sense.

I suspect there are differences in say, stock small block pumps, they wouldn't list AC/non-AC if they didn't I surmise.

 

[ntsqd]

I believe that it is possible to flow the coolant thru the engine too fast. I just don't think that it is possible with the pumps currently sold. And as CyberSniper points out, you wouldn't want that much HP drain anyway.

The better the pump, the more coolant it will move for the same HP demand.

 

[CyberSniper]

Well, I think the trick is to make an impeller/pump body design that can move enough volume at lower RPM but doesn't create astronomical windage losses or cavitate at high RPM.

I know on my buddy's destroked 400SBC, the water pump took like 14hp at 7800rpm (something like that, it was also not turning the belt either and it was like 8 hours later that day). The temperature difference between running an accessory belt driven pump and an electric one wasn't apparent.

I doubt GM made pumps for AC and non-AC vehicles... maybe in the olden days before the short pumps... but they were pretty good at only using one thing... kind of like AC and non-AC radiators were the same by the late 80s. I can picture rebuilders and shady remanufacturers putting out waterpumps that don't move enough coolant though.