Mull Engineering billet impeller questions

[blowit]

I figured I would take a minute to answer a few questions on impeller installations.  We have a lot of R&D in our impeller design to examine both optimal pump efficiency and failure modes of impellers and seals.  

 

The bearing to impeller shaft fitment would ideally be an interference fit (press fit) but is impractical on the Banshee due to design.  For this reason, our shaft is designed to fit tight but not require pressing. If a shaft fits loosely, slippage between the shaft and bearing inner race may occur causing localized heating of the shaft which will then cause seal failures.  

 

When installing our shaft, it is common for the bearing to try and push out of the side cover just a bit so you need to make sure the bearing is seated once the impeller is installed.  In some cases, you may need to tap the outer race of the bearing back in the side cover with a punch being careful to only strike the outer race.  If the bearing pushes out a bit, this will cause poor clearance for the cross pin that drives the impeller drive gear.  

 

We recommend to install the pump all the way into the side cover, then tap it back out about .010" so the impeller blades are not making contact with the side cover housing.  When installed correctly, the pump should spin absolutely free and you should not hear the impeller making contact with the side cover housing.  

 

Brandon

Mull Engineering

[Coupelx]

good ideas. ive seen a few clutch covers torn up from the aftermarket impeller making frequent contact. People dont realize the impeller just "floats" in there.

[mailman]

I just bought one of these billet water pump impellers for the banshee but the pin hole on the shaft seems too low on the shaft.  I can't get the pin in the shaft.  The bearing and the the shaft are all the way in too.  Did you guys get a bad batch of these?

Edited December 13, 2015 by mailman

[mailman]

After taking some measurements, the hole in the shaft seems ok.  The problem seems to be that the fins on the impeller are too tall and bottoming out preventing the shaft from sliding a little further.

[trickedcarbine]

Brandon is quite active here. Have you tried contacting him?

[mailman]

Thanks Trickedcarbine. I emailed him and he replied today.  He said it is pretty uncommon but this has come up a few times.  The fins are too tall and need to be ground down to fit.