Hydraulics questions

[woodlandfarms]

Two questions... One asked by a friend of mine and my own. My PT is rated at 65 HP, but there has been lots of conversations here that it is really only about 35hp. A friend asked why the Hydrostatic tractors only have a 20% drop. I said it was because of the fact they still have transmissions and grears, that the PT is just pushing oil against motors... How wrong am I?

The second is from me. When the lifts go out on the PT, or more money flows in, I want to take out the FEL hydraulics and beef them up to something more along the lines of the 1445. Outside of the steel on the arms, is it just buying a hydraulic piston that is larger (say 2" instead of 1.5" diameter?) or is it something else I am missing?

 

[J_J]

Two questions... One asked by a friend of mine and my own. My PT is rated at 65 HP, but there has been lots of conversations here that it is really only about HP. A friend asked why the Hydrostatic tractors only have a 20% drop. I said it was because of the fact they still have transmissions and grease, that the PT is just pushing oil against motors... How wrong am I?

The second is from me. When the lifts go out on the PT, or more money flows in, I want to take out the FEEL hydraulics and beef them up to something more along the lines of the 1445. Outside of the steel on the arms, is it just buying a hydraulic piston that is larger (say 2" instead of 1.5" diameter?) or is it something else I am missing?

On the first question, what does he want to know, it is unclear. The total Hp of the engine, has to be spread around to run the tram pump, the steering pump, and the PTO, So in some situations, all the pumps are running at the same time. There should be enough available HP to run the machine. The cu in displacement size of the tram pump will be selected to use some of the HP, and the other pumps will use some of the available HP.
Maybe he is talking about efficiency, I believe that hydraulic motors work at about a 80 % efficiency. If you expend 10 hp to run it, the hydraulic motor, will only put out about 8 hp.

On the cylinder size. of course the larger diameter cylinder will give you more power. You are increasing the cu in displacement, and more surface area to push against. Just go the the tech help section of Surplus Hydraulics web site and put your figures in the required blocks. You will need bore size, pressure, and shaft size. Also keep in mind that the push side will have more capable lift in lbs, because the shaft on the other side of the piston is taking up space. If you look at cylinders ratings, you will see push lbs, and pull lbs. You will also have to match up length and end mounts.

Somehing else to think about, even if you replace the lift cylinders with larger cylinders, and you can lift a larger load, you will still be limited by the weight of the machine in order to keep all four wheels on level ground. What that means is that you will have to add extra weight to the back end, and will your front wheel axles be able to stand up to the extra lifting weight.

 

[J_J]

I reread your post and noticed that you mentioned piston size, The piston size has to match the bore. In order to get more power,you have to go to a larger cylinder which will have a larger piston. More surface area.

 

[woodlandfarms]

We were discussing grunt force, and that, using HP as a scale, the PT is lackluster for 65HP.

As for the upgrade on the FEL. I mean the whole thing, piston, sleeve, cylinder... for the life of me I cannot remember today what the name of all of this is..

As for weight, seeing as the my PT is 2 tons, and I cannot lift the rear when the front is weighted down, I have room for improvement.

From what Terry told me, the 1845's and 1850's had the FEL capacity deliberately reduced so that they can keep the 45 degree pitch. From what I understood, you can put 1200lbs and the end of the 1850FEL, raise it to 6 feet, and go tromping across a 45 degree slope with no threat of going over. Above 1200 lbs the bet is off.

For me, 2000lbs of lift would be more than enough. My issue is that with the grapple and bucket, I only have 700 lbs or so of lift capacity. Quite a bit for most stuff, but grab hold of a large log and just sit and spin. My buddies 25hp case lifted the log in question - no problem...

Carl

 

[cqaigy2]

As for the upgrade on the FEL. I mean the whole thing, piston, sleeve, cylinder... for the life of me I cannot remember today what the name of all of this is..
Carl

Hydraulic Ram?

 

[RegL]

We were discussing grunt force, and that, using HP as a scale, the PT is lackluster for 65HP.

As for the upgrade on the FEL. I mean the whole thing, piston, sleeve, cylinder... for the life of me I cannot remember today what the name of all of this is..

As for weight, seeing as the my PT is 2 tons, and I cannot lift the rear when the front is weighted down, I have room for improvement.

From what Terry told me, the 1845's and 1850's had the FEL capacity deliberately reduced so that they can keep the 45 degree pitch. From what I understood, you can put 1200lbs and the end of the 1850FEL, raise it to 6 feet, and go tromping across a 45 degree slope with no threat of going over. Above 1200 lbs the bet is off.

For me, 2000lbs of lift would be more than enough. My issue is that with the grapple and bucket, I only have 700 lbs or so of lift capacity. Quite a bit for most stuff, but grab hold of a large log and just sit and spin. My buddies 25hp case lifted the log in question - no problem...

Carl

Now it makes sense. I wondered why the 18xx tractors only had the same lift capacity as the 1430. If your loader is like mine it's probably kind of fast so I would think a bigger ram would slow that down some. Still leaves the question, is the loader arms, pivot points, etc. strong enough to take more weight.

 

[MossRoad]

You cannot compare the HP ratings of a PT to the HP ratings of a conventional tractor. They do not work the same at all.

A conventional tractor, even with an HST tranny, is not the same drive system as a Power Trac. A conventional HST has a hydraulic pump that pushes fluid that turns a hydraulic motor that turns a shaft connected to the range selector. Then the rear of the range selector turns a shaft that turns a differential. Those are all gears being turned by the hydraulic motor.

A Power Trac has a hydraulic pump that pushes fluid to four hydraulic motors. There are no gears in the system at all, anywhere.

The two types of machines and HP ratings are not comparable at all, in my opinion. You just have to get the machine that will do the jobs that you need to do.

I, for instance, like to get the chassis size narrowed down, then purchase the largest engine I can get in that chassis.

 

[ponytug]

Wow! If this were right, it would explain alot about the Power Trac specifications. If my math is correct, a 54" wide tractor that has a 30 degree slope limit, would have a center of gravity (COG) that is about 45" off of the ground. (Assuming rigid tires, etc.) i.e. contan(45/27)=30 degrees

On a 1445, that would put the COG about 14" above the wheels, which is clearly not the case with the FEL in the down position. In the up position with a full load, you'd have 1800lbs 7+ feet in the air, and a 3900lb chasis low to the ground. I could see how the combination might have a COG close to 45".

Talk about pucker factor! Not something that you'll see me trying.

Anyone who wants to admit having done something like this? Charlie Illiff had a second hand story of someone with the post driver on a 1430 that managed to tip it. A moving 500lbs, 8+' in the air on a 2500lb chasis...

We're looking for real world experience here!

All the best,

Peter

From what Terry told me, the 1845's and 1850's had the FEL capacity deliberately reduced so that they can keep the 45 degree pitch. From what I understood, you can put 1200lbs and the end of the 1850FEL, raise it to 6 feet, and go tromping across a 45 degree slope with no threat of going over. Above 1200 lbs the bet is off.

For me, 2000lbs of lift would be more than enough. My issue is that with the grapple and bucket, I only have 700 lbs or so of lift capacity. Quite a bit for most stuff, but grab hold of a large log and just sit and spin. My buddies 25hp case lifted the log in question - no problem...

Carl

 

[J_J]

HP is HP no matter how it is generated. Whether that HP gets to the wheels, is another question. You should know that some of it is lost due to hydraulic efficiency, and as I said in an earlier post, only a portion of that HP is applied to the wheel motors. So out of that 65 HP, the wheels may only get 35 HP. Does that mean that another machine is better. Not necessarily.
It all depends on how the machine is used.

 

[Charlie_Iliff]

From what Terry told me, the 1845's and 1850's had the FEL capacity deliberately reduced so that they can keep the 45 degree pitch. From what I understood, you can put 1200lbs and the end of the 1850FEL, raise it to 6 feet, and go tromping across a 45 degree slope with no threat of going over.

Carl

I've never gotten a bum steer from Terry, so I suspect there's a communication problem somewhere. If you ever want to test that thesis, make sure there aren't any innocents downhill of you.

 

[woodlandfarms]

I've never gotten a bum steer from Terry, so I suspect there's a communication problem somewhere. If you ever want to test that thesis, make sure there aren't any innocents downhill of you.

Charlie... Watcha' thinkin' on this? That the 1850 with doubles on will go over with 1200lbs at 6ft @45 degrees? Not surprised on communication. I generally only listen to what I want to hear... my career has done much damage to me...

 

[Charlie_Iliff]

Charlie... Watcha' thinkin' on this? That the 1850 with doubles on will go over with 1200lbs at 6ft @45 degrees? Not surprised on communication. I generally only listen to what I want to hear... my career has done much damage to me...

I don't know whether it will go over or not in smooth slow conditions. I haven't done the calculations with precise numbers. In that condition, however, there would be zero room for error. All the weight would effectively be concentrated on the downhill tires. A minor undulation or slide accelerating that high load would greatly magnify the rollover tendency, so I wouldn't bet you'd stay upright. I only have single tires on the 1845. I have the post pounder, and wouldn't want to do any significant side-hill movement with the weight up. When it feels a bit tippy, I believe it. Similarly, on any slope, even fairly gentle, a high bucket isn't static rollover torque if you're moving. A little bit of rocking and you may lose it. Even with the duals, I'd only go on anything steeper than 30 degrees with the big mower on the deck. Ratings are great, but I'm chicken. I'll bet in every forum on TBN you'll find a report of someone who went over with a loaded bucket high -- some on the flat.

 

[cqaigy2]

I don't know whether it will go over or not in smooth slow conditions. I haven't done the calculations with precise numbers. In that condition, however, there would be zero room for error. All the weight would effectively be concentrated on the downhill tires. A minor undulation or slide accelerating that high load would greatly magnify the rollover tendency, so I wouldn't bet you'd stay upright. I only have single tires on the 1845. I have the post pounder, and wouldn't want to do any significant side-hill movement with the weight up. When it feels a bit tippy, I believe it. Similarly, on any slope, even fairly gentle, a high bucket isn't static rollover torque if you're moving. A little bit of rocking and you may lose it. Even with the duals, I'd only go on anything steeper than 30 degrees with the big mower on the deck. Ratings are great, but I'm chicken. I'll bet in every forum on TBN you'll find a report of someone who went over with a loaded bucket high -- some on the flat.

I wouldn't think anybody would make a claim about stability for the reason's you just stated. You might be able to make a claim about the load up all the way on a 45 degree hill if you got rid of those variables and were just standing still.

 

[SpringHollow]

When I talked to Terry, he also said they limited the lift capacity on the slop mowers so they could be used on side hills but I took it to mean that you could carry a full bucket load down low across a side hill. I just would not have even thought that you could do it up high so I did not ask which scenario he was referring to.

Ken

 

[ponytug]

I just spoke to Terry, whose comments, while printable, were along the lines of 'you would be insane to try it'. He said that the lift height/weight were level ground numbers. The transverse slope angle was for mowing, or the load at ~6" off of the ground. Definitely not with the load high in the air.

Drive safe!

Peter

When I talked to Terry, he also said they limited the lift capacity on the slop mowers so they could be used on side hills but I took it to mean that you could carry a full bucket load down low across a side hill. I just would not have even thought that you could do it up high so I did not ask which scenario he was referring to.

Ken

 

[woodlandfarms]

Different than what I heard. Well then, I am indeed going to up the lift of the front. What a bunch of BS to have a 65 hp tractor with 1200lbs of lift... dumb design...

 

[J_J]

Different than what I heard. Well then, I am indeed going to up the lift of the front. What a bunch of BS to have a 65 hp tractor with lbs of lift... dumb design...

Did you ever consider the fact that your cylinders might be strong enough to lift that extra weight right now. That 1200 lb limit they set for your machine, may have been for safety reasons. Go to Surplus Hydraulics, and click on tech help, and input the figures for your current cylinders, and then put in figures for larger cylinders, and check the results. It just might be that any thing over 1200 lbs, would pick up the rear end. So, is there a way around that. Yes, add more weight to the rear end. If you do install larger cylinders, you will probably have to add some weight anyway.

 

[J_J]

Did you ever consider the fact that your cylinders might be strong enough to lift that extra weight right now. That 1200 lb limit they set for your machine, may have been for safety reasons. Go to Surplus Hydraulics, and click on tech help, and input the figures for your current cylinders, and then put in figures for larger cylinders, and check the results. It just might be that any thing over 1200 lbs, would pick up the rear end. So, is there a way around that. Yes, add more weight to the rear end. If you do install larger cylinders, you will probably have to add some weight anyway.

I went ahead and inserted some figures into the calculator.

Bore = 2.5 in
Rod Diameter = 1.25 in
Pressure = 2500 psi

Lift force with that setup, would be over 12,000 lbs, and then, you have two of those cylinders.

Now keep in mind that you have a fulcrum effect with the cylinders, and lift arm setup, and wheel placement. Other wise, what is the weight you can lift at a certain distance.

 

[MossRoad]

Different than what I heard. Well then, I am indeed going to up the lift of the front. What a bunch of BS to have a 65 hp tractor with 1200lbs of lift... dumb design...

Not a dumb design at all. It is a specialized machine. It is a slope mower first, that can also do light front end loader work. It needs that HP to get up those slopes while powering a mower. There isn't a conventional tractor that can do those slopes safely for the price. If you wanted more lift capacity, perhaps you should have gotten a different model.

 

[woodlandfarms]

Wow, interesting replies. Let me firs say to those who I may have offended about bashing PT that there is no bash... I bought my tractor to deal with my slopes first and foremost. So, I am very happy with it in that account. As a matter of fact I am tickled pink with the tractor. It has done everything I have asked of it, except for lifting the occasional heavy item. As for the front end lift, I can live with it, but as I said, I am quite surprised at its limit, considering the weight of the tractor, as well as the HP.

I had understood the design decision to be that it was related to the ability to lift weight on slopes. Now I am told I am wrong...

So, what is the rational to take a 65HP tractor, who's lighter and less HP brethren (the 1445) lifts 750lbs more. If the tractor will go over extended then why not design the tractor to lift at its limits? How is that not dumb to not maximize the potential of a vehicle? What would PT have lost financially to swap the front arms out for the 1445 arms and up the hydraulics? $200 for the upgrade if that I would guess... On a $30K tractor?

As for this my initial question, it was really about the actuality of this pursuit. I was looking for advice on how I would go about upgrading the load ability. In my head, and not on paper, were questions on how do you rate a cylinder, how would you upgrade it? What is the potential downside of upgrading the lift capacity? Does the current lift controls need to be upgraded? Does my draft control and float control need to be adjusted?

If we can start this thread over with this sort of questions in mind I would love to glean everyone's experience and advice. I am a practical person, but hydraulics and the mechanics that govern them were subjects I chose to ignore or sleep through in college.

Again guys, don't take anything I say too personal. It is just a tractor and I am just looking to improve a well designed machine into my personal version of a great machine...

Carl