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Discussion Starter · #1 · (Edited)
Ok guys, I have been doing a bunch of reading and found some great ideas. I have been trying to compile all the info on hydraulics as I can, but I have not found all of the things I am curious about. I am hoping there are a few of you out there that can help me out.

Tractor:
I have a mid-late 80's White 1655. I bought it from a coworker who got it from a friend of his father's long ago. Because of that, I am unable to get much of the history of the tractor. I do know it has been hacked up and cobbled together. It has a peerless gear trans on it that does not appear to have come on the tractor originally (the mounting of the axle on the frame is not factory). It has a 16HP Briggs. The clutch setup is basically a jack-shaft mounted horizontally where the belt coming from the vertical shaft engine turns 90 degrees. The clutch moves an idler pulley on the other end of the jack-shaft which goes to the trans. When I got the tractor I had to take apart the jack-shaft and grease up the moving parts. It had some backyard-fabrication done. I got it to work but I became frustrated with the twisting belt popping off from time to time. I think it had to do with the insane amount of flex in the stamped steel frame, but it exposed a problem I wanted a better fix to than just welding in some stiffeners. FYI... The jack-shaft has the same size pulleys on both ends so the trans is not geared down within the jack-shaft assembly.

Old Way:




Proposed New drive System:
I plan on adding hydraulics for a front end loader and possibly a 3 point hitch lift assist and I will need a hydraulic pump for this. I was wondering if I could set the pump up so the shaft ran vertical like the engine and run a motor with the shaft running horizontal to go to the trans pulley. This would get rid of the twisted belt setup and give me smooth control like a hydrostatic. Does anyone see a problem with this setup?

Proposed New Way:


I am already in the process of building a new frame for the tractor out of 2" x 3" x 3/16" tube. Since I plan on adding a front end loader someday, I knew I needed a rock-solid foundation. The frame will be braced as needed.

Questions:

1) Is this just a dumb, money-wasting idea? (if it is please tell me why this is not an idea worth pursuing)

2) If not, what kind of pump size should I be looking for? (keep in mind I would like to run a front end loader on the same pump)

3) Concerning valves, what kind would be best for smooth drive-ability? (I don't want a 100% on-100% off setup)

4) With the pulleys that are on the engine and trans, when the engine is running at full 3600 RPM the trans pulley is running 2630 RPM. Does anyone know what the torque of a 16HP Briggs is at 3600 RPM? I need to find out what kind of output torque the hydraulic motor will need to have.

Sorry this thread is so long, but I am curious as to anybody's ideas on the subject. Thanks!
 

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Young Buck
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That was once a MTD made tractor just like the 990. IT had a big hydro trans that was shaft driven I believe. It sounds like it's been butchered, but pics would help to know whats been done. I think the 990 used the same rear that my JD 400 used but not sure. You may want to move this to the mtd forum to get better help.
 

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That was once a MTD made tractor just like the 990. IT had a big hydro trans that was shaft driven I believe. It sounds like it's been butchered, but pics would help to know whats been done. I think the 990 used the same rear that my JD 400 used but not sure. You may want to move this to the mtd forum to get better help.
Actually, since the OP is looking to install a hydraulic drive system, the more appropriate forum would be the Case/Colt/Ingersol Forum. There won't be much left that is MTD related other than the front axle by the time he's done. The drive train is gone already and the frame is going next.

:MTF_wel2: , minifarm!!

No, your idea is not dumb. For whatever you think my opinion is worth and if your tractor was originally a 990, your money could be spent more productively by rebuilding the tractor back to the original drive setup. The original Sundstrand hydro/Peerless rear end is a premium combination that takes a horizontal crank engine that will deliver 14 hp or more. It is a very smooth, durable and strong combination and has few equals and even fewer that are better mounted in GTs.

If you plan on installing a FEL along with a hydraulic drive, or a hydro for that matter, the FEL needs its own pump. Typical hydraulic drive pumps put out too much flow to operate a FEL properly. The additional components necessary to allow one pump to do both tasks will make a big hole in the price of a second pump and create a bit of heat in the system as a bonus. Heat is not a good thing if taken to excess. The guys in the CCI forum can set you straighter on this one than I can. They know ways to make it work that I don't.

As far as matching a pump to a motor is concerned, find the ratio for reduction that you need and apply it to the displacements of the pump and motor. Torque is a function of hydraulic pressure, so there is no sweat involved for matching the motor torque. You wouldn't be able to keep the rear tires hooked to the ground to even approach max pressure with useable components.

Hydraulic pumps and motors have an efficiency rating. Due to their design, they leak internally. There is no way to make metal components with close enough tolerances to not leak. The higher the pressure, the more they leak. Gear pumps and motors are 75 - 80% efficient, each. In combination, that translates into 56 - 64% of the input horsepower that will be available for work. Hydros use piston pumps and motor that are 90% efficient. That combination results in 81% useable power for work.

A valve used to throttle a hydraulic system to make a smooth translation from stopped to full speed is going to make heat. How much heat is dependant on how much flow and how much pressure as well as how much time at less than full flow. Hydraulic drive tractors invariably have oil coolers to dissipate excess heat. Some hydro tractors also use coolers and some use a fan and cast in fins on the case. In the case of my tractor, there once was a fan even though the case had no fins. It hasn't even had the fan since the early '90s, but it did mostly winter work. It all depends on how you use it for how much heat is generated and dissipated.

Here are a couple of links that may help you learn hydraulics.

http://www.edgeroamer.com/sweethaven/mechanics/hydraulics01/

http://www.hydraulicsupermarket.com/technical.html
 

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Eliminate the belt in the "Proposed New drive System" and you've copied the Case/Ingersoll Hydriv system. It'd be a lot easier and cheaper just to buy one and restore it.
 

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Discussion Starter · #6 ·
TUDOR - Thanks for the detailed response. Most of the notes I have gathered since joining this forum concerning hydraulics and front end loaders have come from your posts. I didn't realize the pumps/motors were so inefficient. Since it sounds like it would be in my best interest to avoid a single pump idea, I think I should just settle on belt-driving the trans and have a pump dedicated to powering the front end loader. Thanks again!

I think the rest of you guys are right about the tractor being built by MTD, but I am not sure how close it is to a 990. I found a users manual for the tractor and attached a page showing the drive train. The only difference from my tractor and the attached PDF is the original owner removed the trans and replaced it with a 4-speed geared trans. I asked the coworker again today why the switch was made and he thinks it was because the original hydro didn't have the brute pulling force he needed. I can relate to that since an old 20+HP Murray I had with a hydrostatic trans couldn't pull an empty yard cart up a 1% incline.

I appreciate the comments about trying to find an easier and cheaper way, but I am looking forward to the challenge of building a tractor. I worked as a custom fabricator for almost 10 years before moving into the engineering side. I have been in the office designing machinery for the last 10 years and I am itching to get my hands dirty again. Cheap is important, but I don't want it to dictate my decisions too much. Easy is probably even less of a factor. I have never been able to get something and leave it alone. I always tend to disassemble things and re-engineer it to work better. I don't do that because its easy, I do it to better understand the design and see where I need to add enhancements.

I really just want to have a tractor I can use a plow, disc, box blade, and someday a front end loader with. It would be great to build a mini Oliver 88, or a mini Oliver 1650 which were my two favorite full sized tractors on the family farm. Chances are I will get too eager to use the thing before I can spend the time to build the custom sheet metal giving it the old Oliver look.
 

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Thanks for the compliment. The big advantage for using hydraulcs in spite of the inefficiency is how the power can be applied. Gear reductions, alignment issues and shock absorption are all more easily dealt with by hydraulics than belts or shafts. When you take into consideration just how much power you need for a task, the loss factor usually becomes workable. A GT/FEL rarely uses more than 8 hp because you aren't running the engine at more than 2/3 throttle and unless you're pushing the system hard enough to pop the relief, it isn't working at maximum. The loss only becomes scary when the engine is at full throtle and the tractor is moving at top speed uphill towing a heavy load so that the pressure developed is just below the relief setting. That will give you the most power loss, but how often will you operate under such extreme conditions.

I put out those numbers on hydraulic efficiency so that readers can make a decision based on knowledge, not to scare them off. For many, hydraulics is closely related to voodoo. With knowledge we can toss out the voo and get on with the doo-ing. The next step in the process is understanding the actual power requirements of the various tasks so that informed decisions can be made for applying the hydraulics with the associated efficiency factors.

The manufacturers are now building LTs and GTs with big power ratings. If you look back at the tractors from the mid 70's to the early 90's, almost all of the strongest units had engines with less than 20 hp and used implements larger than what you will find for a 24 hp tractor today. My 16 hp tractor had no problem with a 48" tiller, a 54" mower or a 48" 2 stage snowblower. Try to find a 16 hp GT today, period, never mind how many horses they want to sell you to run implements that big. How you apply the horsepower that you have available is more important than having a lot of horsepower. Different tasks require max power at different times. Learn when those times occur and there is little difficulty living with a power transmission system that will only put out 56% of the power available from a 16 hp engine. If you're going to drive your implements hydraulically as well as the tractor, then you really have to take the efficiencies into consideration. But it can't be that hard if Case has been doing it for over 40 years, you just have to learn a little more to match them.

It sounds like your old Murray was either a LT or had a low end hydro, and a tired one at that. High end hydros like the one I mentioned previously have enormous brute force capability and can move trailers weghing several thousand pounds up 3% grades on rough ground, when the tractor is properly set up.

GTs can't deliver more than 8 or 10 horsepower to the ground under most circumstances. You can't load them heavy enough to keep the wheels from spinning before they need that much power. Anything over about a 12 hp engine is strictly for powered implements with most tractors.
 
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