:rofl2::rofl2::rofl2:Yup. It would be nice if the OP would come back and stick his oar in the water.
Since the hydraulic drive tractors that you refer to do not come with 25 hp engines, I fail to see why a hydro tractor would need such an engine. Since even the Sundstrand 15 only requires 14 hp at max performance levels and I have never had occassion to pop the relief on mine at full throttle and full speed, I can only deduce that power requirements for normal hydro use are substatially below that number leaving lots of power available for an implement hydraulic drive system, especially since the Case/Ingersol hydraulic system uses only one gear pump to do both tasks.
Gear pumps and motors as found in the Case/Ingersol tractors operate at an efficiency level somewhat lower than the piston pump/ motor found in hydrostatic tractors. About the best efficiency available in a gear pump/motor combination is 64%, whereas a piston pump/motor combo in a hydro operates at at least 80%. A substantial difference in available horsepower from the same size engine for other tasks.
I agree that most of the tractors built today have vertical crank engines, but more lawn tractors are built than garden tractors, which is the class that this discussion is about. By and large, the vast majority of GTs use horizontal cranks. The newer aero styling does put a cramp on available space for adding a pump, but it is not an unworkable problem.
On my MF1655 I drive my 8 gpm auxilliary pump with a single common v-belt from the end of my primary PTO shaft. In over 2000 hours that belt has been replaced once. Slipping has not been an issue. The 2 gallon reservoir is the posts of the FEL and has sufficient surface area to dump excess heat without the need of a cooler. The pump may look Mickey Mouse sticking out behind the seat, but the shrouding around it conceals it quite well and adds a seat behind the operator. The ideal location for a pump is directly coupled to the engine but that costs the availability of the front PTO. This set-up keeps both PTOs. Log splitters use direct coupled pumps and the same can be done to any engine.
If you can't add an auxilliary hydraulic system to a GT for less than $500 - $800, you're buying premium components and will end up with similar efficiencies to a hydro's piston pump and not a Case gear pump.
And back to you.
An engine must be capable of driving both pumps when those pumps are being asked to put out all they have. Since engines are only new until you start them up, you need to factor in a few extra hp above the known needs, to compensate for the wear and tear that takes place. As you pointed out, the best hydro pumps require 14 hp to power them successfully. The smallest engine used to power the hydraulic system in a Case GT
was a 10 hp Kohler K. It has been said many times that the Case hydraulic system, as designed, can put 12 hp to whatever is hooked up to it. Logic would dictate that you cannot get 12 hp out of the hydraulic system unless you put at least 12 hp in at the front end. So.......if you need 12 hp to drive the Case hydraulic system and another 14 hp to drive the hydro pump, the math says 26 hp.
That's my story....... and I'm sticking to it.
A Massey 1655 or 1855 borders on the sub-CUT sector of the tractor market. Mechanical rear PTO
shafts are few and far between in the world of garden tractors. If you want to make this argument, then shouldn't it be made with the average garden tractor in mind and not the creme of the crop? As for your system, I don't know all the uses you put it to. If it is primarily to power the FEL
, then the 2 gallons of oil in the loader towers is fine. However, this discussion has focused on having a system that is equal to the Case GT
. I suggest that you install a temperature gauge on your system and then hook up a Case rototiller to it. Go to a spot on your property where the lawn is covering virgin soil and begin to rototill that 40 ft x 50 ft area until you have reached the maximum depth capabilities of the tiller and have cross-tilled the area. Do this on a day where the ambient temp is at least 80 F.
Keep an eye on the temp gauge and your watch. Record how long it takes for the oil temp to hit 180 F, then 200 F and then 220 F or beyond. Once you exceed 200 F, you are now entering the territory where hoses begin to deteriorate and so does the oil. Rototilling is likely the toughest task that we ask garden tractors to perform as it calls for the maximum from the equipment used. The Case hydraulic system is constantly asked to put out full flow to the tiller motor at pressures that often range between 1600 psi and 2000 psi on a constant basis, depending upon ground conditions and travel speed etc. You just don't see happening with a FEL
or other cylinder uses.
On the 3100 and 4100 series ALL HYDRAULIC series of Case tractors, the system was often required to power three hydraulic motors at the same time. One motor powered a 48" three bladed mower deck, the second motor powered the Hydra-Vac system that sucked the clippings from the deck and deposited them into a trailer and the third powered the tractor.
In my mind, that's the criteria for duplicating a system that is equivalent to what is available in a Case or Ingersoll tractor. Therefore, someone wanting to convert an existing hydrostatic drive tractor so that it will operate a hydraulic tiller is going to need
- a gear pump capable of 10 gpm @ 3600 rpm, 3000 PSI max pressure
- a six gallon hydraulic oil reservoir
- an oil cooler with 1/2" ports
- some sort of fan to move air over that cooler constantly
- a control valve with built-in relief and 1/2" ports everywhere
- s suitable method to couple the pump to engine
- 1/2" hoses and fittings to connect all the components
- high flow quick couplers to make it simple to connect attachments
What do you have to say about that, Bob? :smile1::smile1::smile1::smile1::smile1: