Paul Lamar wrote of Ian Beadle's water pump pulley failure:

Moving the V grooves out closer to the end of the shaft would
help this situation but hurt the the shaft outer bearing life.
That would mean changing the pulley on the e-shaft and relocating

the

alternator or  relocating the water pump similar to what
Don Dunbar is advocating.

Russell Kent wrote:

OK, so I'm going to expose my engine ignorance here (be gentle).

Why is the water pump shaft so long

(which in turn requires that deeply cupped pulley)?  Was the

engine-driven cooling fan attached to the

end?  Would it make sense to cut down the water pump shaft and

housing, and use a less cupped pulley?

Russell Kent

Originally it had a large fan and silicone filled fluid coupling.
That put a large cantilever load on the water pump shaft which
required wide spread ball bearings. That was what the other four bolts
were for. BTW the mechanical fan has been done away with on the
RX8 and perhaps the third gen but I am not sure.

Paul Lamar

How many hours does Tracy have on his water pump? And does he have 8

bolts vs. 4?  How about Ed?

Bill Schertz

Ed is checking his as we speak.

Paul Lamar

My waterpump & pulley were transfered from the first engine to the one I'm
flying now so it has the total of both engines on it  -  1300+ hours plus
whatever the car it came from.  I've always used all 8 bolts on it.

I seem to remember a similar pulley failure story from the past but can't
remember from where.  The cause turned out to be a small metal chip under
the pulley causing it to wobble.  This would be *extreamly* critical on this
deeply dished pulley so the inside face of pulley and flange of the
waterpump should be squeaky clean before assembly.

Tracy Crook

 
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