A Different Kind of Dyno...

[roverman]

Ex-military centrifugal pump, reportedly for transferring diesel fuel, hearsay rating is 1,100 gpm. @ 1,400 rpm., formerly powered by 4 cyl. Perkins turbo diesel. Pump will be transferring sea water.  Plan is to epoxy coat the cast aluminum internals. Re-power is scheduled to be a Lotus 907, na. motor. Why ? Light, known history/performance and I have it. Dedicated cooling system(rad/etc). Thought is sea water has less viscosity than diesel, so pump will max perform at higher rpm. ?  Gas motor will want higher rpm. Gear reduction if I must. Thought is to monitor output flow vs temp rise, in the pump housing or  pressure gage ?  Your skilled thoughts please ?  Thanks, Art.

[BlownMGB-V8]

Keep your inlet as short and large as possible and watch for signs of cavitation.

Jim

[roverman]

Thanks, anybody else ?

[88v8]

If you can do it without too much bother.... but seawater pumps are made of stainless and bronze..... I would be concerned that when the epoxy coat starts to fail, the seawater will destroy the internals... and then you will need to substitute it with a pump that's built for seawater.
As Jim hints, if it cavitates due to excessive speed, that will happen all the sooner. The casing as well as the moving parts will be affected.

Cavitation would be exacerbated by inlet vacuum, hence the need to keep the inlet big and short, I guess you may need a trash rack and that can cause cavitation issues if it clogs.

Needed HP or rather torque, will depend on delivery pressure.
So that 1100 gpm rating (1500 ft3 / 42m3) needs to be qualified.
http://www.metaris.com/hp-calculator.php

Some pumps, the flow falls off markedly as back pressure increases.
Also, it may not develop much suction, may need to work from a static head.

Uncharted water. Fun if you have time and can afford to throw it all away if no go.

Ivor

[BlownMGB-V8]

Yes, it would be best if you could mount the pump below sea level. I know, go buy a barge and mount it to the floor Failing that, maybe you could have a large inlet tank (accumulator).

Jim

[roverman]

Thanks for info, so far. Since this for primarily water transfer, "maybe" lift 10' max ? Pump has (2) x 4" inlets/outlets and (1) 6" in/out.  Will likely use the (2) x 4"( we have mega 4" fire hose). Inlet screen is an approved, large surface area, friendly to fish, design.  I suspect a pressure gage ,on discharge side of centrifugal pump housing, should tell the story ? With 97 hrs. on the clock, since new, and at $500, all-in, we will move A LOT of water, before we whimper.  Onward, art.