DANdeMAN

Yes, check!

SharkSkin

Bill, that's one of the possibilities that I mentioned in my previous post. Seems very, very unlikely based on what I know about Greg... but not impossible.

Bill51sdr

That's what I get for just skimming over the posts! You just never know what may be floating around in the water jackets on a car you do not own though.

dprantl

You don't need to shorten the belt. If there is no impeller to worry about, the center section to hold the new idler pulley could be more than 5 times as thick and house the thickest bearing that would last forever. It would also be sealed from the coolant itself.

The problem is finding a place where the electric or belt-driven water pump could tap into the block.

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

SharkSkin

The way I read the OP, Greg just finished building this engine from the ground up, I have a hard time visualizing him leaving debris in a water jacket.

Bill51sdr

Good point. We'll see what Greg comes up with soon, I'm sure.

GregBBRD

Yes, that is not a possible problem...there's not even dust in these things.

GregBBRD

I'd have to guess that not many have ordered a factory pump, in the last few years. There is absolutely no stock, in this country....and no recent sales history. I'm having some "car downed" from Germany. I simply can't afford to risk having a water pump seize on one of these engines....leaking is one thing, but seizing is a completely different animal.

Like Roger said, the rebuilts, Lasos, etc. might be plenty good for a $500 engine in a $5000 car, but these custom engines are uber effort machines that don't need to be compromised.....and I sure as hell can't tolerate a water pump that seizes.

What's that old motorcycle saying? "If you have a $10 head, buy a $10 helmet to protect it."

Sounds like some think this applies to cam belts and water pumps, also.

Mark Anderson

Well put Sterling
BTW the current retail list on a new factory pump is $1003 and due to go up next month.

Mark Anderson

I'd like to know what if anything makes the factory pump better. I don't mind spending money on proven quality but show me why.

Ketchmi

We just had the first failure of one of our rebuilds after a year and a half of hard driving by the Wyo. customer. It was leaking, did not seize or damage the block. We had been batting 1000 up until that point with over 150 water pumps sold. So that would be a .66667% failure rate, I can live with that. I had a Devek sourced one fail within 6 months of purchase back in 98', didn't kill the engine but did gouge the block.

Lizard928

I find this thread and ones like it funny.

Bearings, seals etc. all fail eventually and there are always a few which fail almost right away. This is the nature of things.
If you have only had 4 pumps fail in 40 years or so which is the impression I get from your first post. That is a VERY VERY small percentage. And I can tell you that domestics have more failures than that too.

As to the stroker loading it more. The bore and or stroke have nothing to do with it. Belt tension, cam lift, how fast it revs up. These things do. Belt flutter can also have negative impacts on this. but the simple matter is when do you stop being paranoid and just install what you like and drive it. If it fails it is part of LIFE.
As well a shop knows the risks of installing parts and should either tell the customer that should the pump fail replacement labour is not covered. Or charge more for the job so that when one out of every 1000 or so fail you have already recouped lost revenue.

There is someone on this list who is working on a new pump. But I wont give any info.

Then I am using an electric pump. But this is not something that the average user would do. There is alot of fab work. And you have to realise that the electric pump has to be replaced after 2500 hours running time. They are $200 a pop. But they flow more, have less parasitic loss and are better IMO.

Maybe when I get back home I will look more into doing an electric water pump conversion piece. But I doubt it would work for the boosted cars is the only problem.

Mark Anderson

We have sold 1845 pumps in the past 10 years. 77 were returned but most were not because of failure.

heinrich

I think this is a risk-loss discussion. In any risk evaluation, there are 2 factors that both work in concert, to drive risk up or down

1) likelihood of failure. Very likely = high risk. Very unlikely = low risk.
2) loss incurred in event of failure. Very high = very high (and in this case we have a very high loss SHOULD it happen.

Therefore it can be argued that the quantum of damage makes the failure RATE or likelihood of failure, a critical component. If we can drive the likelihood of loss down by even one percent, we have solved the issue. And conversely, even a 1% likelihood of a nuclear event, is unacceptable, because of the massive loss it would incur.

How do we lower the likelihood of a loss event?

1) beefier pump

or

2) replace the pump with an alternative

Colin .... 2500 hours of running a 928 engine is a LOOOOT of driving my friend.

SeanR

I just got done mowing the yard and doing some thinking about this thread. I come back on after a couple of hours and see my thoughts have all been said by Mark, Colin and Sterling.

If .5% of a product fails, and a posts are made and the fear of Ferry is put in everyone, nothing good will come of it. Sort of like yelling "Fire" in a movie theater.

Greg has taken apart several pumps for everyone and kept us away from a manufacturer that had substandard parts in it, I trust what Greg says, but I get the feeling this thread started as a 'vent', but just ended up going the way all these threads do so.

Until someone can come up with a Chevy style, pully driven system, we are kinda stuck with what has worked for the last 30 years for us.