Cheap water pump?
11-04-2015, 06:55 PM
#62
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No, I'm not trying to raise hell here. I'm a newbie trying to optimize and maintain a 928. It was a double surprise to find those pumps on eBay. The first part of the surprise is that they're on eBay at all - from a dozen or more sellers! How many 928 water pump failures are there each year? The second part was the price, which FOR WHAT APPEARS TO BE THE SAME UNIT varies from $40 to $200 - with gasket, shipped.
My engine is non-interference, but of course I can understand the sensitivity of those with later engines in which a pump failure can be a catastrophe. With an interference engine, I'd pay more for any reduced likelihood of such a problem.
Well, my new pump arrived this afternoon. Examination with magnification shows no evidence of a quality issue. It's a great casting, with no flaws. The machined surfaces are excellent. The impeller is fine. I do not know how that bearing should feel, but to me it seems correct. In fact, everything about this cheap and high quarity pump seems ok, and I will install it along with a new timing belt. For economy, I'll use a belt made of twisted panty hose.
My engine is non-interference, but of course I can understand the sensitivity of those with later engines in which a pump failure can be a catastrophe. With an interference engine, I'd pay more for any reduced likelihood of such a problem.
Well, my new pump arrived this afternoon. Examination with magnification shows no evidence of a quality issue. It's a great casting, with no flaws. The machined surfaces are excellent. The impeller is fine. I do not know how that bearing should feel, but to me it seems correct. In fact, everything about this cheap and high quarity pump seems ok, and I will install it along with a new timing belt. For economy, I'll use a belt made of twisted panty hose.
11-04-2015, 06:59 PM
#63
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No, I'm not trying to raise hell here. I'm a newbie trying to optimize and maintain a 928. It was a double surprise to find those pumps on eBay. The first part of the surprise is that they're on eBay at all - from a dozen or more sellers! How many 928 water pump failures are there each year? The second part was the price, which FOR WHAT APPEARS TO BE THE SAME UNIT varies from $40 to $200 - with gasket, shipped.
My engine is non-interference, but of course I can understand the sensitivity of those with later engines in which a pump failure can be a catastrophe. With an interference engine, I'd pay more for any reduced likelihood of such a problem.
Well, my new pump arrived this afternoon. Examination with magnification shows no evidence of a quality issue. It's a great casting, with no flaws. The machined surfaces are excellent. The impeller is fine. I do not know how that bearing should feel, but to me it seems correct. In fact, everything about this cheap and high quarity pump seems ok, and I will install it along with a new timing belt. For economy, I'll use a belt made of twisted panty hose.
My engine is non-interference, but of course I can understand the sensitivity of those with later engines in which a pump failure can be a catastrophe. With an interference engine, I'd pay more for any reduced likelihood of such a problem.
Well, my new pump arrived this afternoon. Examination with magnification shows no evidence of a quality issue. It's a great casting, with no flaws. The machined surfaces are excellent. The impeller is fine. I do not know how that bearing should feel, but to me it seems correct. In fact, everything about this cheap and high quarity pump seems ok, and I will install it along with a new timing belt. For economy, I'll use a belt made of twisted panty hose.
i think those are the belts that greg Brown said stretched a lot.
11-04-2015, 07:02 PM
#64
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Has anyone dissected a pump? I'd like to know the architecture of the bearing and seal. In fact, I'm prepared to sacrifice this new one if it will help with the overall knowledge base.
11-04-2015, 07:04 PM
#65
Also, Laso isn't really the expensive one, try one from Porsche at double that price and some won't install anything but Porsche pumps.
The Geba is the only other smart option and I'm not convinced on how smart it is yet as they are pretty much an untested pump but we are running out of options.
11-04-2015, 07:14 PM
#66
Nordschleife Master
Early Laso's had the metal impeller and they also had migration issues. The vendors here (roger) started a working relationship with Laso to fix the issues the community had and the results were a pinned and plastic impeller. There could have been some bearing changes but I'm not sure. I've got an early Laso sitting here on the bench where the impeller ate it's way in to the water pump as opposed to the block. That was an interesting one.
Also, Laso isn't really the expensive one, try one from Porsche at double that price and some won't install anything but Porsche pumps.
The Geba is the only other smart option and I'm not convinced on how smart it is yet as they are pretty much an untested pump but we are running out of options.
Also, Laso isn't really the expensive one, try one from Porsche at double that price and some won't install anything but Porsche pumps.
The Geba is the only other smart option and I'm not convinced on how smart it is yet as they are pretty much an untested pump but we are running out of options.
Any comment on the Guardian pump ?
11-04-2015, 08:48 PM
#68
Former Sponsor
I'm going to stick to my theory and repeat it here.
If no other company had ever produced a replacement water pump and everyone was forced to buy only Porsche Factory water pumps, the 928 community as a whole, would be tens of thousands of dollars ahead.
The failures of pumps that had impeller migration ruining engine blocks, the additional labor charges for changing defective water pumps, the engines that had cam belt failures from water pumps seizing, the repair of engines from the drive pulleys falling off, the cost of engine blocks that got repaired after I invented my tooling to repair damaged blocks: Add all of this wasted money up and the costs are staggering.
Here's "simplified" 928 water pump information:
1. Use a factory water pump. If you can't afford one of those pumps, sell the damn car and buy a car you can afford. These cars were some of the most expensive production cars built in their day. The are one of the finest GT cars ever made. Neither of those two things happened because they were cheap.
2. Use a factory timing belt. On an engine with the later design "round tooth" belts, you can use a Gates belt. Consider "updating" early engines with the "square tooth belt" to the later design round tooth belt....especially if the gears are worn.
3. Rebuild the factory tensioner and all the associated pieces. Remember to fill it with oil. If you aren't skilled enough to make it not leak oil, hire someone who is. If you have an early non-interference engine and everything associated with the tensioner is junk, consider a Porken tensioner.
If no other company had ever produced a replacement water pump and everyone was forced to buy only Porsche Factory water pumps, the 928 community as a whole, would be tens of thousands of dollars ahead.
The failures of pumps that had impeller migration ruining engine blocks, the additional labor charges for changing defective water pumps, the engines that had cam belt failures from water pumps seizing, the repair of engines from the drive pulleys falling off, the cost of engine blocks that got repaired after I invented my tooling to repair damaged blocks: Add all of this wasted money up and the costs are staggering.
Here's "simplified" 928 water pump information:
1. Use a factory water pump. If you can't afford one of those pumps, sell the damn car and buy a car you can afford. These cars were some of the most expensive production cars built in their day. The are one of the finest GT cars ever made. Neither of those two things happened because they were cheap.
2. Use a factory timing belt. On an engine with the later design "round tooth" belts, you can use a Gates belt. Consider "updating" early engines with the "square tooth belt" to the later design round tooth belt....especially if the gears are worn.
3. Rebuild the factory tensioner and all the associated pieces. Remember to fill it with oil. If you aren't skilled enough to make it not leak oil, hire someone who is. If you have an early non-interference engine and everything associated with the tensioner is junk, consider a Porken tensioner.
11-05-2015, 11:47 AM
#69
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I get why people are tempted to go cheap on the water pumps. They're simple creatures (the pumps, not the people 
) and there's no good reason why a they should need to be expensive. There just isn't! Unfortunately, there is lots of history that indicates the cheap ones are more failure prone, and in these cars, a failed water pump causes a lot of far more painful issues (at least on the interference cars). It would be great if one of the cheap pump manufacturers go it all right, and who knows, maybe they have. I just know I'm not willing to experiment on my motor in order to find out. For me, the Guardian made too much sense: Reasonable price (compared to Laso, Geba, Porsche, etc), I know it's been tested on his test setup, and the most likely failure mode is temps go up and I have to replace it, not that the bearings seize and I have even bigger problems. Plus, it scratches my itch to support innovative solutions from within the community.
) and there's no good reason why a they should need to be expensive. There just isn't! Unfortunately, there is lots of history that indicates the cheap ones are more failure prone, and in these cars, a failed water pump causes a lot of far more painful issues (at least on the interference cars). It would be great if one of the cheap pump manufacturers go it all right, and who knows, maybe they have. I just know I'm not willing to experiment on my motor in order to find out. For me, the Guardian made too much sense: Reasonable price (compared to Laso, Geba, Porsche, etc), I know it's been tested on his test setup, and the most likely failure mode is temps go up and I have to replace it, not that the bearings seize and I have even bigger problems. Plus, it scratches my itch to support innovative solutions from within the community.
11-05-2015, 12:01 PM
#70
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Perhaps someone in S Calif has a high-price pump that I can borrow. I'll perform (and document) a comparative study to include non-destructive testing.
11-05-2015, 12:03 PM
#71
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I get why people are tempted to go cheap on the water pumps. They're simple creatures (the pumps, not the people ) and there's no good reason why a they should need to be expensive. There just isn't! Unfortunately, there is lots of history that indicates the cheap ones are more failure prone, and in these cars, a failed water pump causes a lot of far more painful issues (at least on the interference cars). It would be great if one of the cheap pump manufacturers go it all right, and who knows, maybe they have. I just know I'm not willing to experiment on my motor in order to find out. For me, the Guardian made too much sense: Reasonable price (compared to Laso, Geba, Porsche, etc), I know it's been tested on his test setup, and the most likely failure mode is temps go up and I have to replace it, not that the bearings seize and I have even bigger problems. Plus, it scratches my itch to support innovative solutions from within the community.
) and there's no good reason why a they should need to be expensive. There just isn't! Unfortunately, there is lots of history that indicates the cheap ones are more failure prone, and in these cars, a failed water pump causes a lot of far more painful issues (at least on the interference cars). It would be great if one of the cheap pump manufacturers go it all right, and who knows, maybe they have. I just know I'm not willing to experiment on my motor in order to find out. For me, the Guardian made too much sense: Reasonable price (compared to Laso, Geba, Porsche, etc), I know it's been tested on his test setup, and the most likely failure mode is temps go up and I have to replace it, not that the bearings seize and I have even bigger problems. Plus, it scratches my itch to support innovative solutions from within the community.I trust his quality control more than any "large" company pumping out "new" pumps.
Who's to say the Porsche pumps which used the correct style bearing when Greg checked, switches suppliers tomorrow and starts selling a lower quality pump?
It's not like that never happens in the automotive parts world.
11-05-2015, 02:06 PM
#72
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Does anyone have any first- (or even trustworthy second-) hand knowledge of a "cheap" pump failure? Remember, there must be hundreds of them on the road...
11-05-2015, 02:16 PM
#73
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no one has any experience with the geba pumps ? all this talk is making me quite nervous.. almost ready to go to the dealer and by a factory pump. even that is no guarantee
11-05-2015, 02:42 PM
#74
Did you not read my posts? Yes, many of us have seen/replaced cheap pumps that have failed, and those of us who work on these day in and day out are only a small portion of those who deal with them. So if we've seen it, there are many more out there that have failed.
11-05-2015, 03:26 PM
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When looking at an engine, are there external appearance clues to differentiate a "good" pump from a "cheap" one? If a pump is removed and examined inside and out, what visual cues are there to define "good" vs "cheap"? Ignore the Guardian, which is visually unique.
A local Porsche mech says his shop cannot tell the difference between one of the $$$ brands and a cheap copy. Of course, he denies ever installing a cheap pump...
Maybe the cheap ones are cast in molds taken from good ones?
A local Porsche mech says his shop cannot tell the difference between one of the $$$ brands and a cheap copy. Of course, he denies ever installing a cheap pump...
Maybe the cheap ones are cast in molds taken from good ones?