[C320-list] Changing the Impeller

[Warren Updike]

Good points. I don't know the answers.  
The first time I removed the end caps on our Perkins heat exchanger (another
story,) I found seven impeller blades from at least 3 impellers judging by
the different colors.  Since then I have been using the Globe impeller and
have not had one come apart. I've had some cracked blades, yes, but not one
broken off. 
I really think it is a good practice to remove the impeller and keep it
covered in antifreeze for the winter.  I buy them at Defender.

Warren & Pattie Updike
1994 C320 #62 "Warr De Mar"

-----Original Message-----
From: Donald Lawson [mailto:dnclaws at aol.com] 
Sent: Saturday, May 12, 2012 9:45 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Changing the Impeller

Warren is correct. Rotation speed is the main factor in flow rate. However a
10 blade will push slightly less water than a 6 blade due to the additional
4 blades taking up  more volume inside the pump. Each blade has slightly
less water to push in a 10 blade. It is negligible. Might be that each
blade, of a 10 blade, pushing less water will increase durability of the
blades?
Don Lawson #1005
On May 12, 2012, at 6:12 PM, Warren Updike wrote:

> I am an aficionado of the Globe "Run Dry" impellers (Defender.)  I 
> posed the same question to them and they said the 6 blade and 10 blade 
> are functionally equivalent.  If you think about it, the volume of the 
> area inside the pump and rotation speed are the main factors.  6 or 10 
> blades won't make much of a difference in the flow.
> 
> Warren & Pattie Updike
> 1994 C320 #62 "Warr De Mar"
> 
> -----Original Message-----
> From: Mark Gillingham [mailto:markgill at uwalumni.com]
> Sent: Friday, May 11, 2012 8:32 PM
> To: C320-List at catalina320.com
> Subject: Re: [C320-list] Changing the Impeller
> 
> Another pump question. I was able to get a Jabsco impeller that says 
> it is a replacement for Johnson 810b and is the correct dimensions 
> with a screw for the slotted shaft, but it has 10 blades rather than 
> 6. Do the number of blades matter if the other dimensions are correct?
> 
> Mark
> Speakeasy #612
> 
>