hydraulic pump

allis restorer wrote: I have a allis chalmers D17  and i was wondering if a hydraulic pump off of a forklift would work to run a loader with two way cylinders?

Could you be any more vague?  There are a lot of forklifts and styles of pumps out there, you need to be more specific. 

A pump doesn't care what it runs, as long as supply in and the discharge out is the right size. The pressure rateing of pump matters as to it's design and it's maximum RPM. Volume of pump is set by size and type and the lines that feed or distrubute oil.

thanks for the advice, my dad can get forklift pumps from work and they are toyota forklifts with lift, tilt, and side shift.  they get new fork lifts and they part out the old ones, so the pumps are in good condition. we are going to put a extrenal hyd. tank and run and valve control off of john deere parts tractor. we are planning on running the pump off of where the belt pully would go. again thanks for your in put.

There's a WHOLE LOT MORE to hydraulics than this question asks.

You need to know a whole host of things in order to make a proper system.

Is the pump a rotary vane or gear type pump? 
Is your control valve an open or closed-center design?
How big is your reservoir?
What is your cylinder's bore, stroke, and rod size?  How many cylinders, and on what circuits?
How fast will you need to extend and retract cylinders?
How will you be coupling the pump to the engine?
How much weight will you need to lift, and based on your forklift's geometry, how much force will the cylinders be acting against?

And finally... the non-hydraulic questions:
When the forklift is installed on the tractor...

How far will the MAST FACE located back from the centerline of the axle?
How much weight will you be lifting, and how far from the mast face will you be applying lift?
How much ballast do you plan on installing as counterweight on the FRONT of the machine?
And for terms of safety:
How wide will you have your wheels spaced, what is your maximum off-horizontal operating angle, and how high will you be transporting your load?

EVERY one of these questions is of dire importance when building a machine... especially a forklift.

I'm currently rebuilding a Clark IT-60 forklift that, at the time, had some really clever features... however, time has proven the design to be unreliable and cantankerous at best, and incredibly dangerous under many situations. The biggest portion of the problem STARTED with the hydraulic pump and drive system.

And after noting this... I realized that you asked not about the forklift, but rather, the loader...  but the same issues apply... you're just lifting from the other end, and another way.  Tell us more about what you've got.

Ahh!  THAT's more like the meat we need!

Okay, I'm not familiar with the Kelly, but here's some things you'll need to know:

Most earlier hydraulic implements ran a 'high pressure/low volume' system... and earlier ALLIS tractors ran that combination.  Pressures were usually 3-4000psi, and only a few gallons-per minute... and the valving was predominantly for single-acting cylinders.  High-pressure/low volume implements are characterized by smaller cylinder diameters (often, a 2" cylinder would be about the biggest), and being single-acting, there'd be only one hose coming off the cylinder.

Most early loaders ran with these systems, usually two skinny rams, and the loader lift was only lowered by gravity- you couldn't "force" the bucket down to dig.  The earliest were 'trip bucket', so generally not useful for much past loading manure.

The hydraulic systems in our early tractors are usually driven mechanically from a point downstream of the main engine clutch, so when you step on the pedal, no hydraulic or PTO output.  The secondary clutch gave us the ability to simulate 'live' hydraulics, but still, it wasn't like having modern live hydraulics.

I'm betting the 500 loader is a low-pressure/high volume system... probably operating in the 1500-2200psi range.  It'd be characterized by larger diameter cylinders, and more likely than not, the cylinders would be double-acting, and the bucket would be fully hydraulic.  Tractors of the D17's size fitted with modern live hydraulics would probably have capacity of around 20 gallons per minute at 2000psi or so... and there'd be valveing on the tractor to operate at least two circuits, mebbie even three.

When they built the Series IV, they did something pretty neat... the prior series' clutch shaft had a pinion gear for driving the belt pulley.  As I noted above, the internal pump and PTO were downstream of the clutch-  the belt pulley feature was, too... step on clutch, belt pulley stops.  When they built the Series IV, they totally redesigned the clutch... they made a flywheel couping with TWO shafts- one that always spins (regardless of clutch) and one that stops when clutch is depressed.  The always-spinning shaft drives a pinion that goes to the area where the BELT PULLEY used to be, and in the BP's position, is a high-volume, low pressure pump.

Now, many guys made couplings that'd fit a modern pump to the old belt-pulley arrangement, and this solved the mismatch of old v. new implements.  It did NOT solve the 'live hydraulic' situation, as the pump stopped every time you declutched for a gear-shift.  I'd imagine that there's SOME guys who went whole-hog and changed the housings and shafts to get full-live, but it'd be just-as-easy, and probably just as expensive, to find a Series IV tractor.

The OTHER way it was done (and I'm doing mine right now), is to mount the pump to be driven right off the crankshaft.  Many aftermarket setups did just this, and the front pulley actually has bolt holes for a coupler and shaft that reaches through the front casting... and just out front, you'd have a plate bolted to rails (on each frame rail) holding a hydraulic pump.  This gives you full live hydraulic for the loader, like it SHOULD be.

Of course, having the pump is only a portion of the system... you need a reservoir (rule-of-thumb is a 20 gallon for 20gpm, 10 gallon for 10gpm, etc), good to have a suction strainer in the tank, and a return filter, breather cap, and mebbie a level gauge), and on the output side of the pump, a pressure relief valve to return excess pressure to the tank, and finally, a bank of valves with at least TWO double-acting valves for your loader's lift and curl function, and while you're at it, another for a rear implement.

For the Allis engine, a rotary vane pump wouldn't be my choice.  I tend to use my D17 at all points in the throttle sector, and I appreciate it greatly at dead-slow idle... because it's quiet and strong, and I can be very sensitive in 'nudging' it around gently.  At that idle speed, the vane pump simply won't work, whereas a gear-type pump would.

My recommendation would be to find a pump that'll have suitable displacement to turn out 15-20gpm at 1800rpm.  Here's some basic math:

1 gallon - 231 cubic inches.

20gpm - 231 x 20 = 6420 cubic inches per minute...
at 1800rpm, that's 6420/1800 = 3.56 cubic inches displacement per revolution.

A pump of that size, will typically fall into the "SAE B" form factor.  That has a mounting hole about 2.5" diameter or so, and two mounting bolts.  Shafts come in varieties... I'd probably pick a round shaft with keyway, and slap a small U-joint on it, to connect to the coupler shaft going through the front casting.  Obviously we'd hafta make sure the rotation direction is correct.

There'll be a suction line coming in one side of the pump, and a pressure line coming out.  Mount a reservoir on the side most convenient for suction, because suction lines tend to be finicky... and the pressure side will go to a valve body with pressure relief and valves... return line from valves back to tank will have a cartridge filter.  Probably need somewhere in the vicinity of a 1" pressure line, 1" return, and 1.5" suction line.

Your hydraulic valve body needs to be OPEN CENTER.  This means that when the pump is spinning, but there's no lever pulled, anything coming INTO the valve, goes right back  out the return line to the tank.  This keeps the pump load to a bare minimum when cranking, and when not running any hydraulic implements... it also helps warm up ALL the hydraulic fluid on a cold day.  BTW... make sure your valve assembly is good to at least 20gpm.  Try not to go more than 40gpm, as it'll make your valves 'jumpy' when you're trying to appy finesse.  Again, it's always good to have a pressure relief valve capable of much more than your pump can generate, but as long as you can cover the absolute max (and we're hitting 20gpm with the throttle wide open), you should be fine.  Most of your work will be done at part-throttle.

And since I mentioned it... with your engine running at half throttle, that means the pump's output will be lower... let's say half-throttle gives you 10gpm... that means your bucket raise-lower speed is limited by engine speed.  You COULD go to a much larger pump to get faster bucket speed, but the disadvantage will be a higher shaft-load on the engine to lift a given weight.  Getting the right load-capacity vs. lift speed is somewhat of a 'good guess' situation.  Best way to determine what'll work 'right', is to look into other setups that ran the similar loader, and see what their GPM ratings were... and of course, if you can get the cylinder specs, you can calculate how many gallons it'll take to extend/retract the rams... and by simple math, you can calculate about how long it'll take to do a curl/uncurl, etc.

For what it's worth, when I built up my small loader (a Cub Cadet garden tractor), I ran a toothed-belt drive to my pump, and calculated my bucket capacity/speed based on 2400rpm (a sane level for that engine and tractor) and upper limits at 3800rpm goverened limit), and figured that if the result of my calculations weren't satisfactory, I could always change sheaves on my drive belt, and speed up/slow down my pump accordingly.  Turns out that my math was spot-on.  I'd be willing to bet that yours would come out the same.