M600 lift capacity

[fatjay]

From what I read the lift capacity of hte M600 is 1000lb and tipping weight is 1700lbs. Is the lift capacity a limit of the engine, hydraulics, or both? I get pallets of bricks regularly that weighs about 2000lbs, if I were to half unload it, i should be able to lift the pallet off the trailer. However if i were somehow able to raise the lift power to 1500lb, it'd make life a lot easier. I don't want to go bending a cylinder, blowing a hose, or worse though.

 

[Tazza]

Not saying this should be done, so take this as you wish.
The lifting capacity stated is a combination of relief pressure settings and cylinder size. If you set the pressure and cylinder sizes, you know what amount it can lift. The motor will only really bog right down if you try and push full pressure and full flow to the lift cylinders, so i think you could feather it to get the extra lifting power
BUT
If you were to increase the relief valve pressure, the cylinders can exert more force, giving more lifting power. The issue here is you need to counter balance these forces. You can have a machine that can lift 20,000 lbs but you need the appropriate amount of counterweight on the rear to not allow it to just topple forwards. This is where you will have issues. If you fill your rear tyres with water, you will increase it's weight to help balance.
You then run into issues of hoses, are they good for the extra pressure? if they are old, they really should be replaced and you can use higher pressure rated ones.
To be honest, if you bumped up you rrelief a bit, added some counter weights, you may be ok to unload the full load, but it sure will be light on it's back tyres. I found that my tilt cylinder had more power than the lift, so get under the palette, tilt forward, lift all you can, then tilt back to get it up in the air. Keep the load low and move it to where it's needed. Not ideal, but can get you out of the poo when needed.
I'm lucky enough to have my little machine and a bigger one for the occasional times it's needed for heavy stuff.

 

[fatjay]

Not saying this should be done, so take this as you wish.
The lifting capacity stated is a combination of relief pressure settings and cylinder size. If you set the pressure and cylinder sizes, you know what amount it can lift. The motor will only really bog right down if you try and push full pressure and full flow to the lift cylinders, so i think you could feather it to get the extra lifting power
BUT
If you were to increase the relief valve pressure, the cylinders can exert more force, giving more lifting power. The issue here is you need to counter balance these forces. You can have a machine that can lift 20,000 lbs but you need the appropriate amount of counterweight on the rear to not allow it to just topple forwards. This is where you will have issues. If you fill your rear tyres with water, you will increase it's weight to help balance.
You then run into issues of hoses, are they good for the extra pressure? if they are old, they really should be replaced and you can use higher pressure rated ones.
To be honest, if you bumped up you rrelief a bit, added some counter weights, you may be ok to unload the full load, but it sure will be light on it's back tyres. I found that my tilt cylinder had more power than the lift, so get under the palette, tilt forward, lift all you can, then tilt back to get it up in the air. Keep the load low and move it to where it's needed. Not ideal, but can get you out of the poo when needed.
I'm lucky enough to have my little machine and a bigger one for the occasional times it's needed for heavy stuff.

I'm not saying this is my plan, was just toying with the idea of saving me some time and effort. I already toyed with the idea of putting a suitcase bracket on the rear door, then hanging ~200lb of suitcase weights on the back.

I am getting a full set of new hoses made, the ones that are on it i am not sure would take even the 1000lb rated lift capacity and I don't want to have a hose blow in the middle of winter outside clearing snow. I have a hose shop on hand already that makes hoses for my other machines. 8 hoses is not going to be cheap and the nuts on the end of the hard lines look to be in pretty bad shape, so I'm almost afraid to take them off.

I'm guessing the pressure relief screw is on the controls that the pedals link to? It's kind of a mess down there.

 

[Tazza]

I'm not saying this is my plan, was just toying with the idea of saving me some time and effort. I already toyed with the idea of putting a suitcase bracket on the rear door, then hanging ~200lb of suitcase weights on the back.

I am getting a full set of new hoses made, the ones that are on it i am not sure would take even the 1000lb rated lift capacity and I don't want to have a hose blow in the middle of winter outside clearing snow. I have a hose shop on hand already that makes hoses for my other machines. 8 hoses is not going to be cheap and the nuts on the end of the hard lines look to be in pretty bad shape, so I'm almost afraid to take them off.

I'm guessing the pressure relief screw is on the controls that the pedals link to? It's kind of a mess down there.

Glad you are going to do the hoses, much safer
The reliev should be mounted the the control block, where the pedals connect to. Can't tell you where it is in there exactly and if it is even adjustable, not all are. Some have a screw on the outside to put more pressure on the spring, so you wind it in, then check the pressure till you get where you want it.

 

[fatjay]

Glad you are going to do the hoses, much safer
The reliev should be mounted the the control block, where the pedals connect to. Can't tell you where it is in there exactly and if it is even adjustable, not all are. Some have a screw on the outside to put more pressure on the spring, so you wind it in, then check the pressure till you get where you want it.

Got my forks finished. Went to lift up my shed and got about 2" up when the relief valve kicked in. Going to need to find that adjustable if it has it.

 

[Tazza]

Got my forks finished. Went to lift up my shed and got about 2" up when the relief valve kicked in. Going to need to find that adjustable if it has it.

You may want a 3,000 PSI or 4k pressure gauge to see what you are getting. Hook it up to your aux hydraulic line and operate it, this will give the pressure reading the relief is set to.
If it's not adjustable, and if it can be opened, you can put a thin washer behind the spring to give a little more tension, but go slow, you don't want to over do it and detonate the pump or blow a hose.
See what your pressure is now, and go up say 100 psi and test it again. From my very rough maths (probably wrong too), cylinder diameter of say 2.5" will give a surface area of about 4.9" multiplied by the pressure of 100 PSI is 490 lbs, by two cylinders to give 980 lbs more pushing force from the cylinders, this is not lifting power though due to pivot points. But it means every 100 PSI you add, will increase the forces at each cylinder by 490lbs. There is the potential of reaching a point that something may bend or tear out, so be careful.

 

[Wayne440]

You may want a 3,000 PSI or 4k pressure gauge to see what you are getting. Hook it up to your aux hydraulic line and operate it, this will give the pressure reading the relief is set to.
If it's not adjustable, and if it can be opened, you can put a thin washer behind the spring to give a little more tension, but go slow, you don't want to over do it and detonate the pump or blow a hose.
See what your pressure is now, and go up say 100 psi and test it again. From my very rough maths (probably wrong too), cylinder diameter of say 2.5" will give a surface area of about 4.9" multiplied by the pressure of 100 PSI is 490 lbs, by two cylinders to give 980 lbs more pushing force from the cylinders, this is not lifting power though due to pivot points. But it means every 100 PSI you add, will increase the forces at each cylinder by 490lbs. There is the potential of reaching a point that something may bend or tear out, so be careful.

Remember, the relief valve is there for a reason. You could easily get into the "bending a cylinder, blowing a hose, or worse" that you mention if you adjust it too far. BTW, you have a good excuse to buy a larger machine...