Cummins 330B impeller

[Codger2]

Why are impellers rubber? Why can't they be a geared metal vane pump of some kind?

In this day of high technology, why do we have to live with changing out our impellers every 1-2 or 3 years? I have never understood this.

 

[Steve]

Maybe the metal gear or vane pumps need lubrication? Except for a centrifugal pump I don't remember seeing them in a non oil application.
Steve W.

 

[Bendit]

Rubber impeller pumps are self-priming. Geared pumps are not.

You need self-priming if the pump is above the waterline.

 

[dwhatty]

SeaHorse II wrote:
Why are impellers rubber? Why can't they be a geared metal vane pump of some kind?

In this day of high technology, why do we have to live with changing out our impellers every 1-2 or 3 years? I have never understood this.

Oh Walt! Did you have to change your impeller? :sniff: :smile:*

I, too, change them out every 2-3 years depending on the hours but, until a frustrating experience with the Sherwood pump impeller removal/replacement this spring, have never found it an particularly onerous, difficult or expensive exercise.

Just had Tony Athens' Seaboard Marine raw water pump installed. Neoprene impeller that looks beefy and easier to change out. Time will tell if it was worth it. The yard did opine that it looked like a quality product and asked where I found it.

 

[Edelweiss]

I'm sure there is an expert opinion from somebody on the site.*
But in as few words as possible, A rubber impeller pump creates a significant amount of lift that raising the water several feet above its source, before it reaches the pump impeller, without being primed first.* It's the best pump for our application of drawing raw water into our engines cooling system that is usually above water level.
Gear pumps and rotary vain (slinger) pumps have very little lift capability and must be bathed in or have the liquid (water) very close to the pump intake.
Gear pumps are great for some applications, like moving fairly high viscosity liquids between containers. Rotary pumps can pump very hot liquids, like your engines internal coolant, without damage.* In agriculture, rotary vain pumps for years can reliably take a low pressure water source and pressurize it to much higher levels and spray it through a nozzle to water fields or spray insecticides on crops.
They all have their purposes and this just happens to be the best type of pump for our circumstances. The downside is the impeller rubs against the cam block and pump housing to create the lift and which also causes it to wear out.



-- Edited by Edelweiss on Monday 15th of August 2011 04:48:42 PM

 

[Codger2]

dwhatty wrote:
Oh Walt! Did you have to change your impeller? :sniff: :smile: _______________________________________________________________

******* LMAO* No, as a matter of fact I didn't!* :nana:

As peviously mentioned in another post, I had a Smart Plug installed and have marveled at its obvious superiority over the conventional Marinco shore power set up. This got me to thinking about other components on the boat that I think are inferior. I beieve that the standard rubber impellers that we all have in are boats are poorly designed & until you posted the link to Seaboard Marine, I didn't know we had a choice.

You mentioned that "you had it installed." :jawdrop:* The next time you "have it serviced or replaced", please update us as to its perceived quality vs actual service.

 

[FF]

One of the biggest hassles is operating in shallow water , which has mud or sand particles.

'The rubber impellers are cheap, and easy to change out.

Any other style pump would cost more to replace parts.

 

[dwhatty]

SeaHorse II wrote:dwhatty wrote:
Oh Walt! Did you have to change your impeller? :sniff: :smile: _______________________________________________________________

******* LMAO* No, as a matter of fact I didn't!* :nana:

As peviously mentioned in another post, I had a Smart Plug installed and have marveled at its obvious superiority over the conventional Marinco shore power set up. This got me to thinking about other components on the boat that I think are inferior. I beieve that the standard rubber impellers that we all have in are boats are poorly designed & until you posted the link to Seaboard Marine, I didn't know we had a choice.

You mentioned that "you had it installed." :jawdrop:* The next time you "have it serviced or replaced", please update us as to its perceived quality vs actual service.

*The reason that "I had it installed" was that to get the old pump out, the motor mount near it had to be removed (read "cut out") and the engine jacked up a bit. The motor mount was well rusted due to leaking from OEM pump. I didn't have the skills, the tools or the patience. Yard job. I'll be doing the impeller changes. With greater ease, I hope.

 

[jleonard]

I also went thru the motor mount removal routine on*the 6BTA I had repowered my old Mainship with.

I can honestly say it that timewise it was about the same time roughly to either change out only the impeller, or the entire pump. Both process required removal of something.

To change only the impeller I had to remove the fuel cooler assembly and crunch into a gumby to get access.

To change the pump I had to jack the engine, remove the mount, then the pump, but access to do all that was pretty good.

If you read thru the articles on boatdiesel you will find a way to re-do the engine mount so removal won't be necessary next time. I never got that far with mine since I sold the boat.

But next time.....

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