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darryl
10-25-2014, 06:46 PM
Maybe this has been discussed before, I don't know. The title suggested itself as soon as I got past pressure wash-

Anyway, it doesn't seem to me like it would be a problem. Sure, you would have to figure out the valve so it doesn't wait for hose pressure to begin pumping, but there doesn't seem to be a fundamental problem using tranny fluid instead of water, as long as you keep a closed system and perhaps a relief valve like a power steering pump.

It would kind of make for an easy setup since the motor and pump are already mated, and there's one sitting idle in the garage-

What would I use it for- good question. It was just an idea-

Willy
10-25-2014, 07:18 PM
The pump would already have a relief valve, some are adjustable, but seal compatibility with oil would be my first thought. Also the pump is designed to produce a certain amount of flow (GPM) at a given rpm level. This requires a pressure fed inlet so as not to encounter cavitation or at least a decent amount of head. Having said that I have seen them used with nothing more than a gravity feed system, but water flows much easier than oil, even atf.

A junk yard power steering pump would be less trouble. Not sure of the GPM levels you need.

Doozer
10-25-2014, 09:53 PM
If you make a diesel injection pump out of a pressure washer pump,
now that would impress me.


--Doozer

velocette
10-26-2014, 12:14 AM
If you make a diesel injection pump out of a pressure washer pump,
now that would impress me.


--Doozer

Probably not doable
But many years ago I used a 50 ton press that used a Six cylinder diesel engine fuel pump to power it.

Eric

darryl
10-26-2014, 01:21 AM
If you make a diesel injection pump out of a pressure washer pump,
now that would impress me.


--Doozer

Hmm- you could use the existing swash plate/piston assembly, then extend each piston by edm'ing a hole in each and inserting a hardened pin. The existing head would be drilled for each pin to come through. Each pin would go into a hole in a new head, with some valving, diesel fuel intake and outlet ports, etc, sized to suit. With suitable seals installed, fuel could be pumped using the existing system, and that would pre-pressurize the intake valve system on the second head. The final fuel pressure going to the injectors would be higher by the ratio of the diameter of the existing pistons to the diameter of the pins. A brushless DC motor would drive the swash plate in place of the pressure washer motor. Controlling the speed of this motor would effect the power being produced by the diesel engine.

Frank K
10-26-2014, 12:04 PM
Pressure washer pumps (at least the two I own) rely on the water flowing thru them for cooling and therefore have thermal dump valves incorporated into the bypass line. If you dead head the pump for more than about 2 minutes the dump valve opens to provide cooling flow. Since the water goes on the ground from the dump valve using a pump like this with hydraulic fluid could get messy unless you plumb the valve back to the reservoir.

A.K. Boomer
10-26-2014, 12:25 PM
but seal compatibility with oil would be my first thought.


As would mine - I think it would lunch very quickly... also - what are the components of the pump made from? oil pumps are usually steel and the oil lubricates it, water pumps cannot be steel on steel --- so are those parts compatible with oil too?

Guido
10-26-2014, 01:12 PM
Paint sprayer pumps (airless, HP) are available up to 1 and 2 horsepower, electric or gasoline, and usually use a diaphragm against the paint being pressurized. The diaphragm is actuated (pressurized) by a plunger type pump, moving hydraulic fluid.

Output pressures: 2Kpsi and up. Cat's meow.

--G