Unusual water pump failure?
#16
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One of those situations where extreme situations expose weak spots on our cars components. Judging by the responses maybe a new water pump modifications need to be implemented to improve reliability even if it results in a higher parts price. I know I would prefer a reliable part to avoid self distruction and potential engine rebuild.
#17
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OW! John, that's really painful to look at. Sorry to hear of this.
I'd be looking at pinning the pulley and the impeller, then swaging the pins in place. At least it would be rebuildable...
I'd be looking at pinning the pulley and the impeller, then swaging the pins in place. At least it would be rebuildable...
#18
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At least the block should be fine since the pump spins normally. I was actually impressed with how well the belt survived. It has some nice slices in it from passing over the flanges on the pulley.
Instead of the usual way of using a perpendicular pin, how about a parallel pin (or even better, a set screw) between the shaft and pulley? It would effectively be keying the shaft.
Instead of the usual way of using a perpendicular pin, how about a parallel pin (or even better, a set screw) between the shaft and pulley? It would effectively be keying the shaft.
#19
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I do have some good used valves you can have n/c.
I do see 968 intake valves are a bit lower in price than they were a few years ago.
#20
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Bill--
I'd be concerned about weakening the shaft with a hole for a pin. The stress on the front end of the shaft is significant at times with the belt tension and all. Well, maybe not too bad because the WP is sort of on the slack side, but you get the idea. Maybe a small roll pin right out at the end would do the trick.
I'd be concerned about weakening the shaft with a hole for a pin. The stress on the front end of the shaft is significant at times with the belt tension and all. Well, maybe not too bad because the WP is sort of on the slack side, but you get the idea. Maybe a small roll pin right out at the end would do the trick.
#21
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Bill,
Do you know of any other cases where this particular thing happened? I don't remember seeing the pulley come off the shaft like this.
Do you know of any other cases where this particular thing happened? I don't remember seeing the pulley come off the shaft like this.
#22
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There have been numerous instances of the plastic and metal impellers walking. The damage to blocks from a loose metal impeller is well-documented. Even with a plastic impeller walking, with no damage to the block, the shaft can move forward accomplishing essentially what we see here. I've personally seen one that was caught before the belt was damaged. Circlip fixing of the shaft position would have been a helpful feature too, as on the early automatic TT shafts and on the main tensioner roller. Even if the pulley or impeller don't walk and allow the shaft to move, the effects of overheating from a non-functional pump have killed a few motors. You hope to catch that before it happens, but at least a few have not.
When you look at the "bare essentials" design of the Porsche WP, you wonder how they have the nerve to ask $600 for it.
#23
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Soory to here what happened John. Now I know why Beerfish called and asked if I had a spare pump. I got to see you drive one of the qualiffying laps at SP. I'm the guy his Girlfriend parked behind your car when you were trying to back up. Sorry about that she was not thinking.
If I can be of any help let me know. I live in Fairfax.
It felt really good watching your 928 lap at SP, for this I thank you.
Last year I damaged a head and was pissed off and debated selling. And it was the support here on Rennlist that kept me goin. I am sure you have a ton of support here.
Big AL in VA
84 Euro 928 S2 twin distributor monster
If I can be of any help let me know. I live in Fairfax.
It felt really good watching your 928 lap at SP, for this I thank you.
Last year I damaged a head and was pissed off and debated selling. And it was the support here on Rennlist that kept me goin. I am sure you have a ton of support here.
Big AL in VA
84 Euro 928 S2 twin distributor monster
#24
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Bill..."When you look at the "bare essentials" design of the Porsche WP, you wonder how they have the nerve to ask $600 for it."
Ah, there is a bigger question ...lifted from an article from couple years ago ..." In fact, a current study has discovered that Porsche earns an average profit of $28,000 per vehicle sold. What this means is that with each Carrera that rolls off the lot, they have enough money to buy a couple of Pontiacs of their own.
That $28,000 figure "dwarfs the per-car earnings of virtually any other automaker." By comparison, BMW makes about $3,200 per car, whereas Audi gets about $1,580. When you start looking at higher volume vehicles, the figure drops even further, with Chrysler only making $900 and VW netting $400...."
Porsche has never been shy about markups... Their brand name commands a premium and perhaps is part of why so many people WISH they had a Porsche...
Ah, there is a bigger question ...lifted from an article from couple years ago ..." In fact, a current study has discovered that Porsche earns an average profit of $28,000 per vehicle sold. What this means is that with each Carrera that rolls off the lot, they have enough money to buy a couple of Pontiacs of their own.
That $28,000 figure "dwarfs the per-car earnings of virtually any other automaker." By comparison, BMW makes about $3,200 per car, whereas Audi gets about $1,580. When you start looking at higher volume vehicles, the figure drops even further, with Chrysler only making $900 and VW netting $400...."
Porsche has never been shy about markups... Their brand name commands a premium and perhaps is part of why so many people WISH they had a Porsche...
Last edited by Jim bailey - 928 International; 10-11-2007 at 05:00 PM.
#26
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looks like you were running some good times before it died. too bad.
It also makes me sick to think of the work needed based on this kind of stupid failure.
nice to know these waterpump rebuilds are just crap shoots with 3 modes of failures.
mk
It also makes me sick to think of the work needed based on this kind of stupid failure.
nice to know these waterpump rebuilds are just crap shoots with 3 modes of failures.
mk
#27
Burning Brakes
Originally Posted by mark kibort
looks like you were running some good times before it died.
Thanks for the effort John. Sorry, a lit'l
#28
Fleet of Foot
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I seem to recall that "Loaded", i.e. Fausto had a similar failure with a waterpump practically right out of the box. Fortunately for him he caught it before any real damage was done. I am sure that thread is in the archives somewhere.
#29
All things considered, it was a great day at the track- loved seeing the Shark bombing around SP. It was like a T-Rex among Raptors! We even had a nice dinner afterwards, some beers, and all sorts of automotive topics of conversation. Good luck John- you'll get the old girl back in the fight soon enough.
#30
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Beyond me too. Also, when that No.2 car forced him to drop a wheel off the track coming out of the carousel, John took it in stride. I'm not sure that I could have.