Press on water pump impellers

[flying farmer]

The spare engine I am rebuilding for the Stag is using a water pump and jackshaft from an engine with a cracked block. These were replaced about 5 years ago and have only done about 5000 miles. Unfortunately when I removed the pump it left the brass collar behind

I hoped to get it together without stripping the shaft but it resisted my best efforts so I decided to remove the impeller

I have done 4 or 5water pumpsover the years, and apart from the first one which shattered when I got over enthusiastic with the hammer, I have always managed to get them apart

This one was having none of it, and of course the inevitable happened and I had to carefully cut the shattered remains off with the angle grinder.

The plan was to use the impeller off the pump with the stripped gear, but this new pump is of a slightly different design. Where the old pumps had shallow splines at the top of the shaft to grip the impeller, this shaft is completely smooth:?

I have measured the new shaft and it is about half to one thou fatter than the old one

Question for anyone with engineering experience, will it grip tightly enough to stop the impeller turning on the shaft? I have come across one of the splined sort where the fit wasn't good enough to stop the impeller turning on the shaft, and had to find another impeller. Obviously I dont want to find it coming loose at a later date

Neil

[milothedog]

imported post

I have only ever fitted one, years ago and it came in a box assembled (recon)

That difference would give you an interference fit but I would be worried about the different materials expanding at different rate and it coming loose. you could use loctite on it when assembling it.

Ian.