Aluminum Water Pump Issue

In other words the vaned impeller is better. No argument but where are the numbers?

Where also are the calorie disappation rates of the radiator, or more correctly the cooling system since in this instance the pipes to and from the radiator are also part of the equation?

In fact, adding surface area to those tubes will add to the ability of the entire system to dissipate heat, effectively adding capacity to that system.

The differences between the two impellers was documented by the Ford Trans-am racing team in 1969.

The two impeller designs available remain to this day essentially unchanged.

Given the choice of the two I would select the vaned impeller design but the difference really is virtually negligible to all but a dedicated race car.

Panteras with the inferior paddle design regularly run in open track events and show no significant differences with others in performance.

Doug,

I didnt post the entire articles because they were lengthy. The theory is that the COST difference is the reason there are so many PADDLE STYLE water pumps in automotives. A vaned impeller cost significantly more to produce .. while a street car would never see the benefit of this design.

A vaned impeller was used to cure the TRANS AM high rpm cavatation problem ... but cavatation is taking place all the way thru the rpm range with the open style paddle impeller including idle.

No numbers are specifically posted on the difference ... but there are a host of manufacturers including FORD SVO that label there pump a high volume and wa la underneath is a vaned impeller.

I guess the humor in all this is its like comparing a MISSISSIPPI Paddle River Boat to a Florida Cigarette jet boat ... both push water and get to the other side ?

ROn

I would take an educated guess and say that there is no equipment that is 100% efficient and there probably never will be.

I'm sure that one doesn't need to be an actuary to show the difference in efficiency between these two impeller designs that one is more efficient then the other.

The vaned rotor is the most efficient until something else comes along.

Like I said, given the choice I'd pick it over the paddle but I don't think that if I am running the paddle design that I am in serious jeopardy of any eminent disasters.

But I'd run a pump with the bypass hole and the Cleveland thermostat. A 180. Which is what the thread was before it got sidetracked. ...ok. I'm guilty. So shoot me.

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So shoot me.

Oh, even that would probably cause a disagreement....

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But I'd run a pump with the bypass hole and the Cleveland thermostat. A 180. Which is what the thread was before it got sidetracked.

Hey there is something we agree on ... LOL

Ron

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Originally posted by LF - TP 2511:

Did you just omit that choice inadvertently, or is there a reason you do not endorse it?

Larry

If the recirc passage is blocked and there is a thermostat in operation, then when the motor is cold & the thermostat is closed there shall be no circulation of coolant. The result is the heads are thermally shocked over and over each time the car is cold started. Doesn't your temp gage reading pulsate as the motor warms up? Some guys have gotten around this by drilling holes in the thermostat disk, allowing some recirc through the thermostat. Another method to avoid this would be to open the heater control valve before cold starting the car, coolant would thereby recirc through the heater core.

With the availability of the correct thermostat from Robertshaw there is no reason to botch up the advanced design of the 351C cooling system. So my preferred recommendation would always be to drill out the recirc passage and use the 351C specific Robertshaw thermostat.

I would have answered sooner but my computer & I are both fighting viruses. ho, ho, ho

And so it is said and so shall it be done Senators. Block progress as you will, and insist that day is night.

There are none so blind as he who will not see.

...He sprang to his sleigh, to his team gave a whistle,
And away they all flew like the down of a thistle.
But I heard him exclaim, ‘ere he drove out of sight,
"Happy Christmas to all, and to all a good-night!

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Some guys have gotten around this by drilling holes in the thermostat disk,

Yes, that has been done.

Larry

I'm coming in to this discussion late, but here are a few personal obeservations.....

No matter what people may think, increasing coolant flow in a well designed system will always help cooling....

Newton's law states Q = M * cp *dT or rewritten Q/M*cp = dT

Where Q is the heat load BTU/min., M is the mass flow rate of the coolant in BTU per pound per degree F, dT is the temperature drop through the radiator in degrees F. Thus if M the mass flow increases the dT (temperature drop) is larger.

What may happen in practice to cause poor cooling is the pump starts cavitating. More so in a Pantera where a) the tube under the car feeding the pump is smaller diameter than the pump inlet and b) has a 90 degree bend not far from the pump inlet. In a well designed system high radius bends and tubing of equal size would be used.

The radiator design is the largest restriction to going to very high coolant flows and it is suggested 6-8 ft/sec is optimal (do not exceed 10ft/sec)in a cooling system. Too high a velocity can result in aeration and foaming of the coolant, possible damage to the radiator by overpressure, cavitation of the pump due to excessive pressure drop through the radiator, and erosion of the radiator tubes.

To reduce cavitation one can...

Reduce pump speed - actually not so dumb, get one of those 30% higher volume pumps and use an underdrive pulley to slow it down 30% and your are back to stock volume with a pump running slower and less likely to cavitate.

FWIW some paddle style aftermarket pumps do have a backing plate on the paddles which helps reduce cavitation.

Switch to an aftermarket electric pump which has far less tendency to cavitate.

Increase suction pressure (reduce suction head) - Add a booster pump i.e. a remote electric pump after the radiator. Bear in mind the above 10ft/sec rule.

For my stroker that is half block filled I will go all electric or add the booster pump, probably the latter in my sitution and look at larger tubing.

Julian

Numbers. Interesting.

Two things occur to me on this subject. 1)I presume that the vaned impeller design flows more g/min then the paddle design? 2)I presume that the increased flow of the vaned impeller is below the maximum flow rate of the stock radiator and system, and therefore is usable by the system?

I personally have never found a way to put 10 pounds of mud into a 5 pound sugar sack? Maybe someone here has?

...Cavitation, Cavitation, Cavitation!!! I see that word being thrown around a lot, here. Do You Guys even know EXACTLY WHAT Cavitation really is?? And Why it causes Metal Erosion do to the IMPLOSION of Microscopic Gas Bubbles? In addition, the Automotive 'WaterPump' is a centrifugal pump, that at times will produce ZERO pressure do to the fact the there is NO Seal between the Intake and Output! Now ponder that for awhile! The Physics of Cavitation will be explained here in Detail, upon a request...

...I know I am HighJacking this thread! But since 351C WaterPumps, Thermostats and Brass Restrictor Plates ALL go together; I have included some photos never before seen on this, or anyother forum. The Robert Shaw 333-180 Thermostat,(available at Summetracing.com for $24.64) IN RELATION to the Brass Restrictor Plate, It seats upon. (now I wonder where I can find those at? LOL)

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3 Ofcourse this Thermostat is in the CLOSED position. When OPEN the Lower 'Can' will 'Seat' (or nearly seat)upon the Restrictor Plate as shown.

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5 Stay with the 180 Degrees! 160 is too cold and the only reason You would need a 192 is if You were running Catylitic Converters OR You wanted a Hotter Running Engine to Produce More HorsePower! Merry Christmas!!

Excellent photos, Marlin.

Nice to see both pieces in relation to each other.

Thanks, and hope you had a Merry Christmas.

Larry

I've never had cooling issues since I built my stroker 10 years ago. My temp gauge rises smoothly as it warms up. The temp then stays consistent at around 170 / 180. A little higher in hard driving or traffic.

Lately its been suddenly rising from 180 to 210 over a minute or so and then falls back to 180 just as quickly. This will happen a few times during highway cruising with no change in speed or conditions to cause this. I assumed the thermostat was sticking so I got a replacement.

I got the 330-180 and when I was getting ready to replace it this is what I found inside. Isn't there supposed to be an opening in the center of this ring that the t-stat plugs as it opens / closes?

David,

What you have is a block off plate which is used when you don't use the 351C specific thermostat that has the "hat" which seals the hole in the restrictor plate located under the thermostat.

The restrictor plate with no hole in it forces all the water out of the block all the time, instead of allowing the water in the block to warm up the engine quicker. The restrictor plate you have allows for the use of any thermostat that doesn't have the "hat" on the bottom.

The restrictor plate I use in my car does have a very small hole in it simply to allow for air to eascape the block when filling it up with anitfreeze but otherwise it is identical. Being that I live in the desert and it gets very hot, I run a 160 degree thermostat in mine.

Jim