Importing and modifying a new mini excavator from China

[dfkrug]

So, has anyone upgrade their Pump yet? I figure there is room for more flow.

18L/m @ 2300 PSI only requires around 4.7hp, where a 23L/m pump from say a 1600 machine is only 6hp. And it shows with the likes of a Diggit 15, still running the same 13.5hp B&S

An upgrade to the pump would be to lower flow unit, not higher. This would make the machine less jerky, as I discussed above. The boom, dipper, bucket, and house all move plenty fast now.

I do not know the size of the pump in the Diggit, but it looks larger than the 6.8cc units found in most of the 1-ton minis. Some of the flow goes to the servos, however.

With a 6.8 cc pump, the gasoline engine, running at 3000RPM, will put out about 5.4 GPM. Below 3000RPM, the engine will bog as it does not make much power at lower revs.

If you think you have plenty of power, then crank up the RV pressure to 2600 or more psi.

 

[D'oh]

Thanks, it wasn't power as much as Travel Speed, and Multi Operations at 1 time. And of course, Flow would help Cooling some.

HP is at 3000 rpm but Torque is already decreasing at 2400 rpm.

 

[Fredrik]

So, has anyone upgrade their Pump yet? I figure there is room for more flow.

D'oh, if you find one that will swap out with the briggs coupling I'll try it. Be nice to slow the jerkyness down. Burdans Surpluss may have one I"ll look.
You'll need to replace all motor and valve hose fittings to ones that have larger id constrictors. You might get better travel speed.

 

[dfkrug]

D'oh, if you find one that will swap out with the briggs coupling I'll try it. Be nice to slow the jerkyness down. Burdans Surpluss may have one I"ll look.
You'll need to replace all motor and valve hose fittings to ones that have larger id constrictors. You might get better travel speed.

How are you going to slow the jerkiness down with a higher flow rate pump and an engine that bogs below 2500 RPM?

Have you determined what the volume of your pump currently is, either by reading the label or opening it up and measuring?

Have you determined that there are existing flow restrictors in any of the work-port circuits? Remember that flow restrictors may slow things down, but they also add heat.

 

[D'oh]

How are you going to slow the jerkiness down with a higher flow rate pump and an engine that bogs below 2500 RPM?

Have you determined what the volume of your pump currently is, either by reading the label or opening it up and measuring?

Have you determined that there are existing flow restrictors in any of the work-port circuits? Remember that flow restrictors may slow things down, but they also add heat.

Yes, good point about the "Heat" but they would also help with Prioritizing a Circuit/Route. So they may have Multi Rolls.

All I am pondering is a 1.0T unit has 18L/m pump while a 1.5T unit might have a 22L/m pump. Same 13.5hp B&S XR engine transplanted into it, Same or very similar Hydraulic Cylinders, Valve Bank, Travel Motors and so on.

I think the Power is there, the Jerkiness might be increased, but would there be enough benefits?

 

[D'oh]

Anyone measure the size of the Grease Nipple of the Main Boom Pin. Again, spaz move, thought it was the same size as the Cylinder Fittings, easy out to take it out, tossed it and then found out it wasn't the same size, it is bigger threads.

 

[Rich B1]

Seems I “acquired” an AGT mini yesterday at an auction. Let the fun begin

 

[MattB4]

Perhaps someone can tell me if this is normal. On the operation of my Typhon mini I have noticed that it puts a heavier load on the hydraulics and engine when pushing the boom downwards, more so than any other hydraulic action. It is almost like it is held back from dropping. Is there a valve check and is it adjustable?

Thanks for any comments.

 

[dfkrug]

On the operation of my Typhon mini I have noticed that it puts a heavier load on the hydraulics and engine when pushing the boom downwards, more so than any other hydraulic action.

I have detected no constriction orifice fittings on any circuit of my Rhino (Xiniu) mini. However, that does not mean that no maker has installed them.

I do find that the work circuit for my AUX feature does have more restriction to flow than the others. I run a hydraulic thumb with fairly small diameter hoses. The Oking units had a larger hose fitting for the AUX.

A restrictor in the boom down circuit may reduce jerkiness a bit, but check to see if you have one. You will have to open the console to access the stack valve, which you will have to do anyway if you want to change the control pattern.

 

[Fredrik]

How are you going to slow the jerkiness down with a higher flow rate pump and an engine that bogs below 2500 RPM?

dfkrug, you are correct . Pardon my brain fart.
If one wanted to slow down the jerkiness you would go from a 4.75 gpm pump to something like a 3.25 gpm at 2500 RPM.

 

[MattB4]

I have detected no constriction orifice fittings on any circuit of my Rhino (Xiniu) mini. However, that does not mean that no maker has installed them.

I do find that the work circuit for my AUX feature does have more restriction to flow than the others. I run a hydraulic thumb with fairly small diameter hoses. The Oking units had a larger hose fitting for the AUX.

A restrictor in the boom down circuit may reduce jerkiness a bit, but check to see if you have one. You will have to open the console to access the stack valve, which you will have to do anyway if you want to change the control pattern.

It could be a restrictor since the boom does not drop when operating the the lever with engine off. When I get some time to remove all the covers I'll see if I can figure it out. Though my knowledge of hydraulic controls is fairly sparse. Just enough to replace hoses and valves if I can find the correct ones.

 

[dfkrug]

It could be a restrictor since the boom does not drop when operating the the lever with engine off.

That's a surprise. Of all the units I have seen internally, only the units with servo controls have the solenoid shut-off valve for the boom/dipper/bkt. Does your unit have servos? If you don't, something is amiss in the boom-down work circuit.

It is possible that there is a solenoid shut-off or diverter even if you have no servos. It is a good safety device to have, tho easier to implement if you have servos.

This is why one of the first things new owners need to do it to figure out how their mini's hydraulics work.

 

[MattB4]

... If you don't, something is amiss in the boom-down work circuit.

...

The issue seems to have gone away once I opened things up. The boom now drops easier and also drops when the engine is off and the control lever is pushed. I can only surmised that I had an issue with insufficient bleed off of trapped air in the cylinder and lines.

 

[Colby16]

Hi, I am a noob here. I found this forum while doing a google search. I just picked up a Diggit EM15 yesterday, from a local guy. I played around with it today and find some operations pretty jerky. The boom lift/lower, bucket curl and driving are where I feel it most. Is there anything I can do to reduce the jerky motion of these operations? It is worse at higher RPMs, but still can do it at lower RPMs. I see a lot of discussion on mini x's and being jerky in the discussion threads, but didn't see a what I would call a solution for an EM15. I am certainly new to excavators, as this is the first I have owned.

Does anyone have a owners manual for the EM15? Mine didn't have one when I picked it up and so far I haven't been able to find one online. The seller is suppose to get one, but not sure how long that will take.

Thanks

Here is photo of the new mini, the top was not attached when I trailered it home, I haven't installed it yet.

 

[dfkrug]

I see a lot of discussion on mini x's and being jerky in the discussion threads, but didn't see a what I would call a solution for an EM15.

I see a lot of discussion on mini x's and being jerky in the discussion threads, but didn't see a what I would call a solution for an EM15.

Welcome to TBN. Put your location (state, province, or country) in your profile and we will know where you are.

Jerkiness is a feature of super-light machines. Low weight + fast hydraulics = jerky. This is discussed above, yes, but simply put, these small Chinese excavators use pumps designed to run slower with diesel engines, and the move to gasoline units with faster RPM was not well thought out.

 

[Colby16]

Welcome to TBN. Put your location (state, province, or country) in your profile and we will know where you are.

Jerkiness is a feature of super-light machines. Low weight + fast hydraulics = jerky. This is discussed above, yes, but simply put, these small Chinese excavators use pumps designed to run slower with diesel engines, and the move to gasoline units with faster RPM was not well thought out.

Thanks,

Is there a way to adjust the hydraulics or reduce the flow? Or can the pump be changed out to help reduce it some? Or is this something you get better at controlling over more use? I have maybe 30-40 minutes of operation time at this point. I can fill the bucket quickly and rotate the cab to empty quickly, but I am losing half the bucket in doing so. Any tips?

 

[ptsg]

Wondering if it has the same issue that other poster here had, where the pilot pressure was set too high causing the controls to be hard to master.

 

[dfkrug]

Thanks,

Is there a way to adjust the hydraulics or reduce the flow? Or can the pump be changed out to help reduce it some? Or is this something you get better at controlling over more use? I have maybe 30-40 minutes of operation time at this point. I can fill the bucket quickly and rotate the cab to empty quickly, but I am losing half the bucket in doing so. Any tips?

Discussed above in more detail.

I bought a smaller pump, which would work on any of the non-servo-controlled units. I have not installed it, as I have been able to control most, not all, of the jerkiness with practice (150 hours or so now). I went from 6.8 to 5.5 cc.

The Diggit (see my above pix) has a larger pump that supplies oil to both the servos and the main valve, thru a flow divider. You could also reduce the size of that pump, but no one has yet found out the size.

As with the EM15 I worked on, your main valve RV is prob set too low, and the servo RV could be off as well. No spec to be found on the latter.

 

[bindian]

Dave,
Wouldn't a larger hose slow the jerkiness down some? I know it would slow the speed of motion down.
hugs, Brandi

 

[dfkrug]

Dave,
Wouldn't a larger hose slow the jerkiness down some? I know it would slow the speed of motion down.
hugs, Brandi

Smaller diameter hoses cause restrictions to flow, which slow things down a bit, but add heat. They act like a restriction orifice.

Most of the hoses on the units I have seen are about 10-18mm.

Pump flow is only 5-6GPM.