Contour Enthusiasts Group Archives Forums General Troubleshooting Metal Water Pump Impeller A Good Idea? Maybe Not?

You are missing the point....if the cone is loose...with or without damaging the impeller...THE PUMP DOES NOT WORK..!!!! The cone and the clearence between it and the impeller blades,size of the hole in the involute etc is what makes it a 'pump' Vs just a 'paddle wheel'...get it!....an engine with a metal impeller pump but a loose cone WILL STILL OVERHEAT..! :rolleyes:

Hey, I think this has to do with angular velocity. (Freshmen Physics, why couldn't I pay attention to the prof, and not that little hottie I sat next too.)

I was about to say that the pump rotates at half the speed of the engine, but then I remembered how the pullys look.

Just eyeballing it, it looks like the pump will rotate at about the same speed as the crank.

So my answer is, "purrty darn fast"

Yes, that's my final answer.

Thanks Terry.

TB

I get your point now, .... sorta like the sound of one hand clapping.

OK I am hearing that this is a plastic versus metal impeller issue, but does anyone have any idea what type of polymer Ford's supplier uses? From a material technology standpoint the 'plastic' must be a thermosetting type rather than a thermoplastic type meaning heat cannot be used to reform/remold the material (it does not melt) and that only it's upper temperature limit will cause it to degrade and breakdown. My understanding is that it is a phenolic which means it is hard and brittle unless it has a some strengthening agent such as fibreglass etc. However from a strength comparison the 'plastic' impeller will be and order of magnitude or 2 less in strength than metal like steel. As for efficiency of pumping the 'plastic' impeller being more efficient than a metal one is purely a manufacturing issue and a dependent on cost. Metal impellers are used in all kinds of pumps and are of high efficiency. I have designed all kinds of pumping systems from small to large from 2 inch piping up to 14 inch piping and the calculations are the same and take into account the same basic parameters. The pump is chosen from ones available to do the job. It is not designed from scratch for the project. If Ford wanted to use a high efficiency metal water pump instead of plastic it could have used a cast metal or forged metal one from those that exist already. Even metal stamping processes can produce parts of the desired shape given the correct steel material used. This was a cost per unit issue for Ford given other physical parameters for the water pump. It was a trade-off. Ford made the decision based on expected lifetime and overall manufacturing costs for the car. They made a mistake. It is that simple. Replacement ones that are of metal impeller design will be appropriate for the engine if selected for quality rather than cost. Choose carefully.

As far as the metal pump being shallower?

Mine was not. The blades on my metal pump were about 1/16" longer than the plastic ones. They were also thicker and yes, the pump was heavier. This rotational mass could, I suppose, hinder acceleration, but the mass is not huge and is fairly close to the axis of rotation.

Terry, what exactly are you calling the cone?

My impeller exploded in about 10 pieces. The bearings in the pump also felt rough compared to the new pump.

The 'cone is the s/steel insert in the back half of the pump housing..it matches the angle of the pump vanes and allows a minimal clearence between itself and the impeller, the hole in the center controls the amount of draw/volume the pump can move at a given speed...if the cone is not in place the 'assembly' is no longer a pump....

the cone is a piece of metal (about 2" diameter with a hole in the middle) that sits in front of the impeller. when you take the front half of the pump off, you're staring at the cone if you look into the rear half of the pump housing (still on car). it is held in place with punches in the aluminum of the rear pump housing. the two metals are dissimilar, so my thought is that the different expansion/contraction rates are what causes the problem with the cone coming loose. mine was loose, luckily no overheating or broken impeller...i had ford put a new one in under warranty.

EDIT:
damnit terry beat me to it.

Here's a good visual (taken from Ray's writeup in the FAQ):


I assume (incorrectly) the "cone" we are discussing is the piece of circular metal surrounding the impeller pin.

So....

It seems apparent that the plastic Ford used originally does not hold up well, as well as the cone deal in the housing being of poor design. But is it still possible that plastic is the better way to go, just w/the right type of plastic. (Perhaps no one knows for sure?)

So is it possible that the Ford replacement pump has a different (more durable) type of plastic? It *is* a different color (white vs. black). I'm assuming the the cone design is still the same - held precariously? Or does it look any better?

From what I've read, it's a bigger pain (not to mention more $$$) to replace the whole pump as opposed to just the guts, so I'd really rather not go the Ford route anyway. But, the cone is in the housing(?), so if you just replace w/an aftermarket guts pump, you still are using your old cone & housing, right? Only the Ford pump is the whole works?

And isn't it also possible that the aftermarket plastic impeller pumps use a different (more durable) plastic, so they may hold up a little better?

I started this thread because a run on Contour WP's at the store got me thinking that I have been putting this off for too long & had better get mine replaced!!! I had a customer come in the other day saying that she had to have Ford install 3(!) WP's in her '95 Contour within a few weeks - Ford's story according to her was that they were getting defective pumps - I'll bet you anything that the impeller was hitting the cone. The same day, another customer came in needing a WP for his Contour. (So now we don't have any at the store - if I decide to go plastic, I'll have to wait for our next delivery.)

FWIW, yesterday I asked a Ford tech, who is one of our regular customers, if he had seen a lot of bad Contour WP's - he said that they have had to replace a lot of them at his dealership, but he knew nothing about the plastic impeller deal, or if the new pumps were supposed to be improved.

The cone is NOT shown in that pic, its in the back half of the pump..........