ROG100

As some of you know, I with the help of others, have been looking at the Water Pumps for our cars and trying to understand the failure modes. Also considering new v rebuild.

Vendors that sell rebuilds have reported failure rates of circa .5% which is very low but still a risk when it comes to failure on our cars, partucularly the interferance engined models.

My issue with rebuilds is that we have no control over how many times the casting, roller and impeller are reused for rebuild. The bore ID of the casting must degrade with repeated replacement of the seal cartridge. It is after all an interferance fit. We have already discussed failures associated with migration of the impeller and seal cartridge.

Options for new and fresh Water Pumps are few. Porsche of course but BIG $ and the possibility that it has been sitting on a shelf for years.
Laso sells new but at $260 its still more $ than most want to pay when rebuilt can be had for $100+. There is an advantage in buying new as there is no core charge to mess with.

One avenue I will possibly go down is to purchase new pumps in quantities that will bring down the price to circa $130 to $150 each and no core charge. This would include the gasket and TDC pointer in the case of both the early and late pump types. On the 87 to 95 WP's the tensioner bolt ($40) and support bracket are also supplied.

These are from a German manufacturer using the same casting type as Porsche (GPM).

Before I invest a s**t load of money what are the comments from the members of this board?

Thanks for your time.
Roger

mcholdfast

You could count me in for at least two of the new ones before next spring at the $130 to $150 price.

M. Requin

Ditto here for one new one within 6 months. I really like the idea of a new casting for less $!

BC

I think it would be a good idea, but its not my money invested. There are only 60,000 928s, and only a portion actually working, on the road.

That said, I think your investment and time would be worth it if you could try and be a middle man for other distributors (small) so that you would have enough product "flow" to benefit your pocket book. What do we have here on rennlist, 1000 928s? What about the 15,000 that are probably around getting WPs? You need to get the word to them that there is a good part, priced well, that they can mark up themselves and still be cheaper than others. Dealerships, small garages, small online parts sites.

docmirror

This is a tough one. You have to put up first, and hope they sell. Trying to convince customers that the extra $20-40 for a new one might be a problem for some owners. I know, and most DIY guys know that the cost of failure, and the cost of just getting to the WP dictates that you get the best possible.

Having said that, we don't know the failure rate of the new one either. It could have a different, but still catastrophic failure mode that would be about the same rate as the rebuilds. I would doubt that, but it's something to think about. We just don't have enough cars for a case study on the two. It's kind of a crap shoot, more for you than for us.

As a consumer, I think the price point for me would be about $20-25 between rebuilt and new with no core charge.

David L. Lutz

Its a no brainer for me. I'm in and put me on the list.

123quattro

When it comes to parts like this on my car, I have no problem spending the money. I would always prefer new over rebuilt. My 928 isn't interference, but my A6 4.2 is. I did the Tbelt on it two summers ago. It was $550 for the belt, rollers, tensioner, water pump, and thermostat. None of it probably needed replaced, but it's peace of mind and goes with the territory of owning cars with 4 or 5 valves per cylinder. Kind of like people that run 87 octane in high compression engines. They buy an expensive car, and then try and save $100/year running crappy gas. I just don't get it.

wildwestsydney

If a new pump were only $30-$50 more I would go for it.

dprantl

I would definitely go for the new one for that little extra, but as others have said, people like us on rennlist may be a minority.

Dan
'91 928GT S/C 475hp/460lb.ft

bronto

Roger, I trust you and your products implicitly, but this issue is scary given the complexity of the product. This isn't a oil pan seal or motor mount. I would think that normal product engineering would require a significant amount of engineering and field testing, but there just aren't that many 928's out there. How many installations running for how long will "prove" the quality of the design? How would I (or you) know that this unit would be any better than the infamous Chinese ebay units out there? I don't have an answer for that. The thought of a Porsche unit sitting on the shelf for 15 years is scary too I admit. A new 3rd party unit or even a rebuild by a quality supplier seems less so. I am glad I decided to get a MY with a non-interference engine though

To clarify, I know that you would not knowingly put out anything but a superior product, but how would you know for sure given the small numbers of installations and the long time spans needed to evaluate MTBF?

blandis

I will be needing one as soon as we have TB/WP GTG. With my 16V I dont have the issue of engine damage... but really dont want to tear into it again if a WP fails. The extra few bucks is well worth it assuming the failure rate is lower.

JWise

Roger- perhaps you should put up a poll for this.

I'd gladly pay a little more $$ for one. That said, mine shouldn't need replacing for another 2-3 years (due to age, not mileage).

smudaaar

This seems like an awome deal. I bought a nos porsche pump this past summer for 300 shipped!

JHowell37

I'm in. I'll be replacing my timing belt in the next few months and upgrading to the Porkensioner. My current Laso hasn't had any issues, but the simple fact that they aren't considered suitable cores for rebuilding has left me with considerable doubt regarding their quality.

docmirror

Sounds like you've got some takers. I'd be interested in seeing it put on a few non-interference cars and run for a few thou. Get some idea of the reliability that way.