jcorenman

Go back and read post #29. The biggest concern is the type of bearings, which is not discernible from the outside. Other considerations are quality of the bearings and seals, and whether the press-fit is correct. None of that shows from the outside, either. General appearance also doesn't mean anything, as it is very easy to make sand-cast replicates of any water pump.

The factory pumps are die-cast, which requires expensive tooling. I've never seen an aftermarket 928 pump that was die-cast. However a rebuilt factory pump will look the same as a new one, which gets back to the discussion about rebuilders and how you can't tell whether the rebuild is any good, unless you know who rebuilt it.

So how about this: Buy two of the cheap eBay pumps, cut one open and if you find a roller bearing then use the other one.

notaguru

That's a good idea. I have a complete mech engineering lab, and can do that. The pump in the car is original Porsche, so I'll slice it open as well. I'll document the project.

But what's wrong with a roller bearing in that application?

Mark Thornton

I now own two pumps the cheap one I bought 6 months ago from Ebait and now the Laso To tell the truth the Ebait looks like a quality pump but the box it came in Looks definatly Chinese origin Scared me to put it in.. so I bought the Laso I don't know if the pump in my car is orig or aftermarket (166k on the clock I presume no) i have not ventured in the job of replacing it along with the Belt I bought the Continental belt can anyone tell me if that was a bad choice or not?

stuartbrs

Greg mentioned the different bearings... and gave all the reasons why the cheap pumps should be avoided. There is no way I would use one on my car, no way at all. "You pay for what you get".

jcorenman

Nothing. Please re-read post#29. The problem is the use of a ball bearing as the front bearing, it will not take the timing-belt load.

Yes, sorry, but the Conti belt is a bad choice. Get a Gates or factory belt.

docmirror

Bueller? Bueller? Bueller?

polecat702

Ed's "Guardian," was only 400 bucks when I bought mine, 2 or 3 years ago. He's got a video of how he does the rebuild, and then he test runs the pump a 6000 rpm, before he ships them out. Nobody else does this, and the pump frigging works! If the belt takes a dump, or a bearing, or the impeller were to migrate,( it can't cause he pins the impeller to the shaft) the coupler will shear, and save the engine.

This in my honest opinion, is only way to go. The way Ed makes these pumps, you get a superior product, that was custom built for you're car!

I'm on my 3rd, long distance trip, since I installed the Guardian pump, with zero problems!! Plus it survives the heat in Las Vegas, where I live.

MainePorsche

Thanks for that.

bureau13

FWIW, I just paid $450 for the Guardian, and I believe that included shipping and gasket. I have not installed it yet, but will soon.

Barry Chan

If somehow you proof them wrong you will save the community a lot of money

notaguru

"Proof" is in the numbers. For the 928 water pump, a "proof" would require that we:

• Assemble a statistically valid number of cars - say 1,000?
• Fit one fifth with each of Porsche, Guardian, Cheapo, Laso, Geba.
• Drive them all similarly, in similar environments, for N miles.
• Record the failures as they occur.
• At the end, disassemble and inspect, and count the imminent failures.

Do this enough times and the cumulative result will eventually converge on "proof."

However, I have only one (non-interference) 928, one Porsche pump with 68k on it, and one cheap one. If my cheap pump has one ball bearing and one roller bearing, and dye penetrant shows no flaws in the casting, I'll buy and install another one - and will publish the results here.

But my result will not prove much...

Wisconsin Joe

One problem with the "sample of one" of cheap stuff is the fact that QC on cheap stuff is very variable.

One might be excellent, last for a long time and work very well. The next three might last a couple months before failure.

I've seen that first hand with "other than car" stuff.