More torque for my Power trac?

[KentT]

I thought Stray had the White motors (high torque in PT's vernacular).

He has the 12.5 ci White RS, not the larger White CE motors...

 

[Gravy]

I'd bet that's all suitable steel material. What I wanna know is: Does it fit in the engine compartment?

 

[stray]

So everyone will know my machine is the old stile 422 2003 robin engine model. I run Mobil 1 synthetic oil in the engine and high grade synthetic hyd oil in the Hydraulics. For the last several 50 hr Power-trac recommended oil and filter changes I now do every 100 hrs. I have 800 hrs on this PT and feel like it runs as well or better than it did when I bought it used with about 75 hrs on it. I am very pleased with its performance. In saying about my power problem the closest I come to Bobrips reasons is number 5. (Some people push their machines harder and expect more) Remember I have the weaker pump and wheel motors and only the 22 hp engine. I am expecting this machine to do it all, pull and speed. I hope to get it to perform as well as the new 425s. It is just a challenge to me. When I prove this system arrangement works well I most likely will be changing the Quick disconnects out for solenoid valves. Flip a switch to change gears. Maybe I am just dreaming but that is my goal.

The block is mild steal and the pipes are schd 80 steal. Thanks JJ I will be carful. Nothing will need to be disconnected to or from the front wheel motors. The hoses that go from them to the rear motor will just be removed from the rear and a disconnect placed on that end. Two new hoses are required for the rear motors. And two will be required from the pump to the block. Only 4 new hoses needed.

Gravy I hope to answer your question in the next day or two. There is not a lot of extra room in the engine compartment. Is there? (All that stuff has to go somewhere in here (see pic)

Thanks Guys.

 

[stray]

Ok the work is done but I haven稚 tried it out enough to comment. I went ahead change the engine oil and filter and the Hyd filter. AS it looks now to change the hyd filter I need to remove the unit. It痴 not that much trouble. I will post again after I have tried the tractor out more. As it is when I finished and pulled the Pt back into place in the shop I ran it up again the block wall gave it peddle till one of the front tires spin. Also I can tell already that it is defiantly geared much slower. Some of the Hoses could be made to a better more compact length but if I fill this gear is useful I plan to go the solenoid route anyway. I will do a neater more compact job then.
And yes I know. When the weather gets a little better I will give it a bath.

 

[MossRoad]

Looks good. Can't wait for the test results. Get out a garden hose and flood some dirt and do the mud test!

 

[SnowRidge]

Looks good. Can't wait for the test results. Get out a garden hose and flood some dirt and do the mud test!

There is nothing like East Tennessee dirt. A flea market in Sweetwater has a vendor that sells T-shirts dyed red with the stuff.

 

[J_J]

Ok the work is done but I haven稚 tried it out enough to comment. I went ahead change the engine oil and filter and the Hyd filter. AS it looks now to change the hyd filter I need to remove the unit. It痴 not that much trouble. I will post again after I have tried the tractor out more. As it is when I finished and pulled the Pt back into place in the shop I ran it up again the block wall gave it peddle till one of the front tires spin. Also I can tell already that it is defiantly geared much slower. Some of the Hoses could be made to a better more compact length but if I fill this gear is useful I plan to go the solenoid route anyway. I will do a neater more compact job then.
And yes I know. When the weather gets a little better I will give it a bath.

I am still trying to figured what you did. I am assuming that you have all the wheel motors plumbed in series. If that is true, you have now divided the psi across each wheel motor, Now, each wheel motor is getting the same volume, and if one wheel spins, you will still have traction, but reduced somewhat. You have also reduced you top speed. You just have to do a weight transfer., which isn't easy. Your best traction will occur when each wheel has the same weight on it, and this is rare when going up hill, but can be compensated by the front attachment, to shift weight.

 

[stray]

Sorry Moss but this set up will not be good for the mud. I need to make it clear that this set up gears the Pt lower but will not help traction. In fact without flow compensators the traction will be much less. There would be a tendency for one wheel to spin and rob power from the others. What I am hoping it will do is haul a large bucket of dirt up a steep dry pond bank. It really needs to be fixed to where one can switch back and forth with a switch while on the fly. If the gear seems to do the pond thing then I will install the solenoid valves to do this.

JJ the system is as you said. I call it parallel. It divides the flow into four different routes instead of two. The pump (while holding the same peddle position) will need to pump twice the fluid to travel the same distance as before. The pump (while holding the same peddle position) will only need to produce half the pressure to apply the same push or pull. Now of course this statement excludes other factors such as spinning wheels.
I should be able to test the system this weekend.

 

[SnowRidge]

You could add flow dividers to each side to prevent a spinning wheel from getting all the fluid.

Example Flow Divider

 

[MossRoad]

... In fact without flow compensators the traction will be much less. There would be a tendency for one wheel to spin and rob power from the others. What I am hoping it will do is haul a large bucket of dirt up a steep dry pond bank. It really needs to be fixed to where one can switch back and forth with a switch while on the fly. If the gear seems to do the pond thing then I will install the solenoid valves to do this.
....

When I hill climb with a load, and things start to spin, I back off the pedal a bit, as discussed in other posts. If that doesn't work, no matter how slow I try to go forward, the spinning wheel still spins due to lack of traction, not lack of power(torque). I've never run out of power, just traction. I have turf tires, by the way.

I'm curious to see how it works out for you. Best of luck this weekend.

 

[BobRip]

You could add flow dividers to each side to prevent a spinning wheel from getting all the fluid.

Example Flow Divider

That looks like a good idea. I don't know if it will allow going back and forth between modes.

 

[J_J]

Stray,

Are your wheel motors rated at 1500 psi , or 3000 psi?

 

[stray]

JJ. Kent said 2250 PSI, peak, and intermittent at 1750 PSI. I am not sure what the tram pump puts out but they should handle it because as I said with the rear wheels in the air while pushing on a dirt pile the front motors would be receiving the full psi pump pressure.
Bobrip one might need to let off the peddle when switching modes but surly it would switch then.
Thanks snowridge that may be what this system needs to prefect it. It does regulate in both directions doesn't it?
Moss you are rated 3 more HP than mine. I am sure that makes some difference. Question? Say if you have a full load in the bucket (800 lbs of dirt) on dry blacktop what grade would it take to stall your PT. Now if your system is routed like mine the back should not spin unless the front does.

 

[J_J]

JJ. Kent said 2250 PSI, peak, and intermittent at 1750 PSI. I am not sure what the tram pump puts out but they should handle it because as I said with the rear wheels in the air while pushing on a dirt pile the front motors would be receiving the full psi pump pressure.
Bobrip one might need to let off the peddle when switching modes but surly it would switch then.
Thanks snowridge that may be what this system needs to prefect it. It does regulate in both directions doesn't it?
Moss you are rated 3 more HP than mine. I am sure that makes some difference. Question? Say if you have a full load in the bucket (800 lbs of dirt) on dry blacktop what grade would it take to stall your PT. Now if your system is routed like mine the back should not spin unless the front does.

This is MHO, thinking out loud.

In a series circuit the pressure at the pump must be the sum of the pressure drops across the motors.
This circuit is most efficient where the load on each motor is the same, but when one motor is spinning, you lose climbing power, and the only to fix that is to have equal weight on each wheel, which is hard to manipulate. It is not impossible, because something like a weight shifting device would transfer weight to the wheel that is spinning.

If you put them all in parallel, those 1750 psi motors will see up to 3000 psi, on each motor. I am thinking that at some time, you will exceed the hydraulic limitation, and blow the seals or what ever. It appears that they selected those motors for a series arrangement, and then put those circuits in parallel. I believe that all my motors are 3000 psi motors, and can take the full pressure from the VSP pump. If I want more torque, I have to increase pressure, Which is not feasible.

 

[SnowRidge]

If those wheel motors are the 12.5 cu RS200s, they are rated at 1,500 psi continuous, 1,750 psi intermittent, and 2,250 psi peak.

 

[J_J]

If those wheel motors are the 12.5 cu RS200s, they are rated at 1,500 psi continuous, 1,750 psi intermittent, and 2,250 psi peak.

Therefore, my point. You could put a relief valve if it does not already have one, in the circuit, but, don't know what will happen. If it does relieve anything above 1750 psi, the fluid will heat up fast and further reduce the efficiency.

So, in a test of this circuit, a pressure gage is warranted and a temp gage also.

 

[MossRoad]

JJ...
Moss you are rated 3 more HP than mine. I am sure that makes some difference. Question? Say if you have a full load in the bucket (800 lbs of dirt) on dry blacktop what grade would it take to stall your PT. Now if your system is routed like mine the back should not spin unless the front does.

That's a good question. I don't have any place paved or concreted steep enough to try it. I've always made it up the slopes or spun the wheels but never stalled the engine.

 

[J_J]

Stray,

Here in Florida on my place, it is all flat. As far as stalling, whenever you exceed the weight limit/torque that the machine was designed for, you will do one of two things. 1. If you have a good pump, and good engine, when you come up on the stall point, the relief valves will cut in. 2. If you spin a tire or two tires, then you are asking the other wheel motors to take up the slack. Does anyone know the regular weight on each wheel motor? How about the weight on each tire when you have a full bucket of wet dirt? I am not a mechanical engineer, but there is some calculations needed when you know the static limits, and then to know the conditions that are present on an incline, the weight on each wheel will shift somewhat. Going up a hill with a full bucket, you are adding weight to the front wheels, and reducing the weight on the back wheel. In that situation, I would expect the rear wheels to slip or spin, and even though you have the extra weight on the front wheels, the two wheel motors are not enough to overcome the load on an incline. The spinning wheels is lost energy, and if you could add some weight to the spinning wheel or increase the torque then it might happen.

If your engine stalls out, It means that you have a weak engine, or you are running all the pumps at the same time, or the relief valves are not working as they should.

 

[stray]

Ok so far this is what I have found out. The new system works well. The PT will climb places with loads that before I would not even attempted. As we thought one wheel has potential to spin but with a little practice as JJ said this can be overcome. This tendency can be a good thing if one was worried about too much pressure to the wheel motors. But then I really do not think this would be a problem. As time goes on I will report more findings whether they are good or bad. I want to be totally non bias in my findings.
I imagine that having the larger wheel motors might be better in ways and if one was not concerned about losing speed the larger wheel motors I believe would be better. If a person wants to have more torque and only wants to spend about 200 dollars verses the cost of 4 new motors then this defiantly would be a good option. Sorry I did not try this sooner so at least the ones that bought the bigger wheel motors could have had the choice of the two options. Any way most of us do not worry about spending a few extra dollars we just want our machines to work well and do what we need and want them to do. Me? I wanted speed and power. Before unlike some of your machines (like mosses) I did not have. Thanks guys for all your help and comments.

Oh and I took out a big stump that had been on my list for years. I use one of the attachment not meant for stump removal. Can you guess what it might have been. I will report on this later. Where is that thread on unusual uses for attachments?

 

[MossRoad]

Hey, glad it worked! You going to evaluate it this summer to see if you need/want a solenoid to switch it over? I wish we could dyno test it to see what the actual gains are. Pretty simple conversion you did, really. Nice.