Timing belt failure - Water Pump ?

[82-928]

My 1982 928 shut down in traffic . . . . . . nothing worse!
Now back in the garage and remembering a smell of burning rubber just before shutdown, I figured it was the timing belt. Now with the front of the motor off, I see it was pretty messy; the belt disintegrated. I have been maintaining this one for almost 25 years and, in the past, replaced the belt when it was still in tack. I can’t remember brand of last belt but it went in less than 10k ago. I just got everything open, but tensioner and idler bearing are ok, but the back of the belt looks bad, so I grabbed the water pump and tried to turn, and it does not. I can’t think of any reason that an installed wp should still not turn by hand, but am I missing something? I do remember replacing pump way back, and do not know if it has metal or plastic impeller. If it broke apart, it could now be frozen and not turning and therefore caused the burning of the back of the belt. However, I don’t see a polished mark on the wp pulley which would be expected, unless this causes an immediate failure.
I guess what I need from you guys is experience on the following:
Should the wp turn by hand installed it the motor?
What is a good brand for a rebuilt water pump?
What is a good brand for a timing belt? ( square tooth )
Any other cause for belt failure?

Thanks, Jim

[harborman]

Originally Posted by 82-928

My 1982 928 shut down in traffic . . . . . . nothing worse!
Now back in the garage and remembering a smell of burning rubber just before shutdown, I figured it was the timing belt. Now with the front of the motor off, I see it was pretty messy; the belt disintegrated. I have been maintaining this one for almost 25 years and, in the past, replaced the belt when it was still in tack. I can’t remember brand of last belt but it went in less than 10k ago. I just got everything open, but tensioner and idler bearing are ok, but the back of the belt looks bad, so I grabbed the water pump and tried to turn, and it does not. I can’t think of any reason that an installed wp should still not turn by hand, but am I missing something? I do remember replacing pump way back, and do not know if it has metal or plastic impeller. If it broke apart, it could now be frozen and not turning and therefore caused the burning of the back of the belt. However, I don’t see a polished mark on the wp pulley which would be expected, unless this causes an immediate failure.
I guess what I need from you guys is experience on the following:
Should the wp turn by hand installed it the motor?
What is a good brand for a rebuilt water pump?


What is a good brand for a timing belt? ( square tooth )
Any other cause for belt failure?



Thanks, Jim

Too bad about your problem. Yes, the water pump should turn freely by hand! I used a Laso new, not rebuilt, pump on my replacement, although the stock pump was still good (38K miles on engine). Give the guys your mileage on the engine so they can help you further. I just put on a Gates T belt on my car.

[Landseer]

Jim, search this waterpump stuff on rennlist . com. You need to read whats written there.

[Mrmerlin]

Roger@************ has new Laso WPs for about 250.00 the pump should turn by hand and not have any side to side motion and the bearing should have some resistance to stop the shaft when you spin it.
From thew sounds of things you need to replace all of the parts of the belt run that have bearings just because they still turn doesnt mean they are good,
also consider replacing your fuel lines there are 5 of them in the engine compartment

[LUFTMAN]

Was belt tension correct ? I have factory belt tension tool part#9131 spring scale gauge no longer available simple and easy to use on 2 valve motors for sale $50.00 shipped to you . E-mail me if interested pics. Available. You are lucky that those engines are non interference models. No bent valves regards tom balto. Md.

[bwmac]

Are the fuel lines pre made. I really want to replace them but would prefer to get pre-made stainless steel colored wire braided hose.

[Landseer]

Why? They are buried under stuff.

[82-928]

Thanks to all.
Have not yet pulled the water pump, but it could well be a poor quality rebuild, I’ll post it if I can identify.
Thanks for the sources for the pump and belt on previous threads and renn, I should have done that first, but I am new to Forums.
Bearings in idler and adjuster shaft are within tolerances for their use and in fact I think I remember replacing the idler last time in. I’ll check out the adjuster when I get it out, but after the “catastrophe” I can’t determine accuracy of adjustment. I set the belt tension with a guage last installtion and again in a few weeks.
Yes this is indeed not a catastrophe compared to cruising down the Interstate and suddenly having valves in conflict with pistons.
All fuel lines are relatively new and I have even replaced the “rails” to the injectors.
For those interested, this euro 928 has 80k and is driven regularly, but does not accumulate a lot of miles. I have done a LOT to this thing but still enjoy the ride. This time in I think I’ll also be chasing an oil leak. First glance, looks like front main. I’m guessing front main shaft seal because I did lose the rear; had to replace the clutch with the rear seal on that one.

[928 Go Go Joe]

Once you have the water pump out, you need to inspect the water pump impeller housing in the engine block, also known as the "volute" for gouging and related damage. If it's very bad there are a few different method to repair it. Good luck, hope all is well.

Joe

[Mrmerlin]

buy the new water pump from Roger dont use a rebuild

[bwmac]

The best price i see on that W-pump is $299

[ROG100]

I sell the Laso Water Pump for $275 including the gasket.
The only other choice is the Factory Porsche WP at $1000+.
Do not use a rebuild.
Roger