Water pump cavitation damage - anyone had this?

[02GF74]

Anyone haa a P6 timing cover disintergrate due to cavitation from the water pump?

At high rpm, the impellor creates small bubbles that wear away the surface of the alloy until it becomes so thin it crack/leaks; it looks like its like highly polished corrosion.

Below is picture of a Range Rover.

Does anyone know what the P6 pump impeller looks like - from memory I think it is like a set of paddles; I'm sure I have seen other types where it is like a tapered spiral -for sure the shape would make a difference so I am wondering if thje P6 does not suffer, then it it the impeller shape.

 

[harveyp6]

This is quite common, particularly on the range rover because of the way the pump sits up higher with less to wear through. And it's made worse by not using corrosion inhibitors. If I remember rightly because the pump sits higher on the front cover on the range rover the leak gets noticed because it is external, but if it's a P6 it leaks into the timing chest and doesn't get seen. Whether it's because of cavitation or corrosion on the P6 I couldn't be sure though.
I've also seen the front covers damaged after accident damage hit right on the nose of the pump.

 

[steveg1664]

I had exactly this problem on my MGB GT V8 and was also told by the "specialist part supplier" that it was due to cavitation in the pump. My late father was one hell of a motor engineer and an expert in aluminium and alloy castings. He studied the old damaged parts, the new parts and in particular the impeller and decided that the problem was poor quality casting. The fault he found was called porosity and does not mean that the metal was actually porous just full of tiny pin holes on the surface, these allowed the water to erode it. We polished the offending area and filled it with aluminium solder then polished it again. Later when I was tuning the engine an engine specialist told me to try and find a Buick timing case and pump as these are far superior to the Rover items, along with the crank, rods and pistons.

 

[chrisyork]

That makes sense SteveG. The Buick engine was die cast but the volume production capability didn't exist in the UK at the time. So Rover re-engineered the Buick design to be sand cast.

Chris