Few more 416b questions

[futuresweets10]

As stated in my other thread, I finally got the back hoe going and able to do work. I have been playing with the pressure for a few days and have a few more questions. I found somewhere on line where it listed the pressure for a 416 at 2699PSI. I got it up to about 1950 and it was running good, but didnt have enough lifting power when digging. I had someone digging while I was watching the gauge and I ran the pressure up to about 2500 PSI. It started acting alot more like it should be acting, but when the engine is idled down you can hear it kinda struggling to stay running if you hit a lever. I assume this to be normal as the hydraulics werent made to be run at idle. Am I right about this?

After the pressure increase everything was good for about 10min worth of digging and then we blew a line. It busted right in a curve (the line for the bucket curl and the bust was where the line curves to go around the arm). I assume the line busting is normal considering it set up for a year before I got it and the line busted where it went around a curve. Should I be concerned about the pressure with the line break, or is 2500 ok? Was the line break just due to age most likely?

Thanks guys...

 

[AKKAMAAN]

but when the engine is idled down you can hear it kinda struggling to stay running if you hit a lever

as I posted on post#46this low pressure can impact on engine when idling....try to play with it a little.....raise the stand-by pressure to 600-800psi and see if engine reacts different when you touch a lever...that stand-by pressure might be subject to "tuning" a littlke

I assume this to be normal as the hydraulics werent made to be run at idle. Am I right about this?

I don not think CAT would design a system that kills the engine when idling if a lever is touched (signal to pump), but indeed it could kill engine if you pull lever full stroke and load signal is maxed out....
Also remember that that load signal pressure plus stand-by pressure will sum up to the actual pump supply pressure...so if you increase stand-by pressure to much, you might exceed the cut off pressure on the pump....

The signal pressure max limit should be set by a separate pressure relief valve, probably built into the control valve.....

It busted right in a curve (the line for the bucket curl and the bust was where the line curves to go around the arm).
I assume the line busting is normal considering it set up for a year before I got it and the line busted where it went around a curve.

Unless the bend radius was to narrow and/or the hose was slightly twisted when plumbed into the system, it is not normal that hoses just bursts like that....the is always a reason...narrow bend radius in combination with twist, gives the hose mechanical stress (on the steel wiring) already at the assembly....and then when hose get pressurized, stress increases big time... could also been outside abrasion involved

Should I be concerned about the pressure with the line break, or is 2500 ok? Was the line break just due to age most likely?

make sure the hose is rated for 3000psi.....rating is basically a function of hose diameter and layers of steel wiring....

You are doing very good futuresweets10....You'll be a master on this 416b, when you are done......true learning by doing, and not giving up....I'm "proud" of you....:thumbsup:

Please, keep posting updates...

 

[futuresweets10]

Unless the bend radius was to narrow and/or the hose was slightly twisted when plumbed into the system, it is not normal that hoses just bursts like that....the is always a reason...narrow bend radius in combination with twist, gives the hose mechanical stress (on the steel wiring) already at the assembly....and then when hose get pressurized, stress increases big time... could also been outside abrasion involved


make sure the hose is rated for 3000psi.....rating is basically a function of hose diameter and layers of steel wiring....

You are doing very good futuresweets10....You'll be a master on this 416b, when you are done......true learning by doing, and not giving up....I'm "proud" of you....:thumbsup:

Please, keep posting updates...

The hose that was on it is the factory hose with the factory bend/radius. I know its not normal for a hose to bust just because its in a bend, but my logic is that being an hold hose who's time was probably up anyway, the bend area had more stress due to the constant flexing over the years.

Also remember that that load signal pressure plus stand-by pressure will sum up to the actual pump supply pressure...so if you increase stand-by pressure to much, you might exceed the cut off pressure on the pump....

So if I have the stand by pressure set on 500 and I set the load signal pressure so that when I pull a lever the gauge reads 2500 does that mean the pump is putting out 300 PSI or 2500 PSI.... I would assume if the gauge says 2500 then thats what its putting out, but from the way you described it it seems like it would be 3000

 

[AKKAMAAN]

So if I have the stand by pressure set on 500 and I set the load signal pressure so that when I pull a lever the gauge reads 2500 does that mean the pump is putting out 300 PSI or 2500 PSI.... I would assume if the gauge says 2500 then thats what its putting out, but from the way you described it it seems like it would be 3000

I assume the gauge is sitting on the pump outlet supply line through the whole test process...
2500-500=2000>>>load signal is 2000psi
pump supply pressure is 2500psi
stand-by pressure is 500psi

If you now increase standby pressure to 600psi, max pump supply pressure should read 2600psi. if not the bigger valve on the compensator, is cutting max pump supply pressure off.

To read the max possible pump supply pressure, the cylinder have to stall!!! Thats because it is a Load Sensing, LS, system. Stall=max load, motion is NOT max load.

To measure the actual signal pressure, the gauge have to be T'd on the signal line (1/4" hose) that goes to the compensator
If you measure the actual signal pressure while operating, it will show different pressure all the time , depending on what cylinder/motor is providing the current highest load pressure....

 

[futuresweets10]

I assume the gauge is sitting on the pump outlet supply line through the whole test process...
2500-500=2000>>>load signal is 2000psi
pump supply pressure is 2500psi
stand-by pressure is 500psi

If you now increase standby pressure to 600psi, max pump supply pressure should read 2600psi. if not the bigger valve on the compensator, is cutting max pump supply pressure off.

To read the max possible pump supply pressure, the cylinder have to stall!!! Thats because it is a Load Sensing, LS, system. Stall=max load, motion is NOT max load.

To measure the actual signal pressure, the gauge have to be T'd on the signal line (1/4" hose) that goes to the compensator
If you measure the actual signal pressure while operating, it will show different pressure all the time , depending on what cylinder/motor is providing the current highest load pressure....

The gauge is on the pump pressure line through the whole process, so if it says 2500 then thats what the pump is putting out. I just wanted to make sure thats all it was putting out so that I didnt try to push too much pressure through the system. I had assumed that max pressure was measured when the cylinder would stall. When I was adjusting the pressure I would watch the gauge while I had someone digging. I would watch for the highest spike pressure on the gauge.The odd thing is that the gauge would pretty much only read 2500 at the max. I am thinking that even though the machine is listed at 2699 PSI that is probably the max the pump is capable of putting out and the compensator cuts it off at 2500 PSI.

 

[AKKAMAAN]

The gauge is on the pump pressure line through the whole process, so if it says 2500 then thats what the pump is putting out. I just wanted to make sure thats all it was putting out so that I didnt try to push too much pressure through the system. I had assumed that max pressure was measured when the cylinder would stall. When I was adjusting the pressure I would watch the gauge while I had someone digging. I would watch for the highest spike pressure on the gauge.The odd thing is that the gauge would pretty much only read 2500 at the max. I am thinking that even though the machine is listed at 2699 PSI that is probably the max the pump is capable of putting out and the compensator cuts it off at 2500 PSI.

Try to increase the max pressure then....the larger valve on the pressure compensator....

btw...the 700$ CAT book says 2750PSI.....