Importing and modifying a new mini excavator from China

[dfkrug]

I read in an earlier post that you had a lower volume pump you were going to try on your machine, did you ever try it? I love my new machine but even with the pilot controls, it seems to have way to much flow making it much more jerky than it needs to be. And why would they put on a 2 stage pump with a single output? The pump switching stages during operation can't be good for smoothness and control. It may also make it harder to reduce flow by simply throttling down.

I would love to try a new pump with about 1/2 the flow as the one I have now. In an earlier post you estimated current output at around 6 GPM I believe? I would prefer slower and smoother to the way it operates now, WAY too fast for my taste. I want it to be a more relaxing experience and stress the machine less, I am in no rush.

Yes, I have a smaller pump, but I have not installed it. My early machine has a custom splined coupler, unlike newer units with Lovejoy couplers. This potentially requires that I have to remake my coupler if I change to the new pump. I would love to lower my pump volume a bit, but right now, I am living with the current flow.

Be careful about going too small on the pump. I went down to 5.5cc from 6.5cc. And, the pilot controls require you have 2 pumps, or a flow divider.

You are correct that a 2-stage pump does not make sense. Reports I have seen so far say that the the switch from low to high volume does not seem very noticeable, which indicates the load-sensing pressure setting is close to the system RV pressure. That means it acts like one big pump. For both the pilot controls AND the main valve, you may want a total flow rate greater than mine (6.5cc), but lower than what you have (unknown). So far, this is uncharted territory, AFAIK.

If you try something, please report it. It is easy to figure the GPM flow rate if you have the pump volume and the RPM the engine is turning. If you use the B&S 420cc gas engine, it will work best between 3000 and 3600RPM. I am usually at about 3000. Any of the diesels are happy at about 2000RPM.

 

[JohnnyB24]

I just got the machine and only have about 1 hour on so I definitely don't see the big picture and I am not yet a proficient operator. As soon as I get some hydraulic adapters for the new thumb (M16X1.5 Male O-Ring to M14X1.5 Female) and the weather dries up a bit, I will be heading north to my lake property where it will get a very god workout.

After I return, I will do some mods like replacing the existing internal tank filter with a 10u external one like you recommend. Will that filter alone be enough for the machine or would you also replace that existing ilot filter so all the return fluid is filtered

Yeah, that filter is in the return part of the circuit, draining to tank. That is good, but what is the spec on it, and how do you find replacements for it? At least they addressed this critical need. I would change to a known and serviceable 10u filter setup like what I did above.

Thx for posting the filter pix. I will check again the local EM15 to see if it has this somewhat hidden filter.

Well, curiosity got the best of me and I removed the floor plate for a good inspection. It looks like a small hose goes from the lower left side of the flow divider directly to the input of the filter just below the seat. I say input because of the red arrow on the filter housing. The output of the filter tees off and one hose goes to each of the pilot hand controls. Does that sound like it is a pressure filter?

I plan on taking it apart during my next fluid change for further analysis and hopefully determining what a replacement filter would be.

I would pay a lot of money for a good service manual and a parts list!

 

[dfkrug]

After I return, I will do some mods like replacing the existing internal tank filter with a 10u external one like you recommend. Will that filter alone be enough for the machine or would you also replace that existing ilot filter so all the return fluid is filtered

You could tee the return from the pilot valves to the IN on the return filter you are going to install, and use only one filter.

Looks like they put a hi-pressure filter on the IN line to the pilot controls. Strange. This filter will see the full pressure from the pump, regulated by the pilot RV, which is probably 500-1500psi. A proper return pressure filter usually is designed for no more than 500psi, and that's when it starts to resist flow.

I hope they chose that pilot pressure filter properly.

 

[dfkrug]

I would pay a lot of money for a good service manual and a parts list!

I hear ya. For an additional $20K or so you can get a nice manual and parts list. It will even come with a shiny new Kubota K008 mini-X.

As a minimum, it sure would be nice to know about the pilot valve RV setting, and that supply line pressure filter.

 

[Fixastuff]

This tmis

I hear ya. For an additional $20K or so you can get a nice manual and parts list. It will even come with a shiny new Kubota K008 mini-X.

You don’t have to add hydraulic pick up extensions, hydraulic filters, cut holes in the cab for vents, or be unsafe with no proper rops or fops protection and have nice smooth quiet diesel(I know you can get a Chinese 1 ton with diesel but from what I can most are not).


These things are great for a home owner but let’s not pretend the only difference between these and a name brand mini is only a manual. lol.

Oh yeah your forgot if you talk sweet you can get a hat included for your 20k.

 

[JohnnyB24]

Don't get me wrong, I really love the mini ex and I the more I tear into it and understand how it works, the more I like it. It certainly has fit and finish issues with bolt hole alignment and cover fitment, but overall, its built well and I think they are really an incredible value, especially for person who has a wife that will just not let them buy that expensive Kubota!

I'm retired now, but I spent my career in Aviation maintenance and that world is ALL about proper documentation and detailed procedures. It just seems like these manufacturers are limiting their market simply because of the lack of a basic manual and list of major parts. It just can't be that costly to have a technical writer (or a secretary) compile a list of parts used in building the machine and who made them.

I do actually enjoy working on it though, and it will be fun to customize it in the future to make it better than new. Kind of make it your own I guess. No computer controls and locked down software, If you don't like something, change it!

 

[Rich B1]

Most pilot hydraulic systems on CE I have been involved with have a pilot filter on the supply side. You don’t want crud getting into a joystick.

 

[JohnnyB24]

Most pilot hydraulic systems on CE I have been involved with have a pilot filter on the supply side. You don’t want crud getting into a joystick.

It seems like a good idea to have that filter. I'm thinking or replacing the Chinese housing with one with from Grainger (or similar) which is about the same physical size but has 1/2 ports. I could even tee in a pressure gauge on the filter output port to monitor pilot pressure. The filter Housing is about $50 and replacement elements are $13, not a terrible price and maybe I can find one cheaper. It's 25u so it will still let the primary return filter do the really fine filtering down to 10u as the fluid eventually cycles through the entire system

Of course I will have to deal with metric adapters and that world is still mostly a mystery to me.

 

[JohnnyB24]

I noticed the exhaust was blasting against the rear door of the mini due to the muffler outlet being short and not aligned with the cutout in the rear door. This was causing extra heat buildup and unwanted noise in the engine compartment. It has the BS 420cc

A piece of 1in galvanized pipe was just a bit too large to fit inside the muffler tip but after a touch on the grinding wheel to dull and taper the threads, it fit perfect. Next, a slot was cut in the pipe most of the way through then bent, cut and bent again until the angle of the pipe allowed it to align with the center of my door cut out. Grind off the galvanized coating in the weld area and weld it up.

After threading it in, a pilot hole was drilled and a self tapping screw was added to keep it from vibrating loose since it's not really threaded in.

It was already pretty quiet, but it's even better now.

 

[dfkrug]

I noticed the exhaust was blasting against the rear door of the mini due to the muffler outlet being short and not aligned with the cutout in the rear door. This was causing extra heat buildup and unwanted noise in the engine compartment. It has the BS 420cc

That's a step in the right direction.

Note that the stock muffler also puts out a ton of heat, and it is completely enclosed inside the house.

The off-the-shelf screw-on mufflers I have used are not as quiet as the OEM, and they DO have to be unscrewed to open the rear door or panel, but they do work even better for heat removal.

I can operate my machine without hearing protection, but I may upgrade my muffler to one of those larger rectangular ones commonly seen on 5000W generators.

 

[JohnnyB24]

I really have not faced up to the heat issue yet, I'm waiting until I head to the lake to really put some time on it and see how bad it is.

I do like quiet though, and being able to open that rear door easily is a plus for me but cooler operation may be more important than that. I read that you had talked bout your exhaust before but I don't believe I saw pictures of it.

Next up is figuring out a way to drain the oil without flooding the machine floor and making a huge mess. Do you think the drain plug is 3/8 NPT? And does it have a magnetic tip? I would like to have a short pipe extension with a cap similar to what my snow blower has if that is possible. I still have my break in oil in it and don't want to change it yet or even lose any oil removing the plug momentarily for a peek.

 

[dfkrug]

Next up is figuring out a way to drain the oil without flooding the machine floor and making a huge mess. Do you think the drain plug is 3/8 NPT? And does it have a magnetic tip? I would like to have a short pipe extension with a cap similar to what my snow blower has if that is possible. I still have my break in oil in it and don't want to change it yet or even lose any oil removing the plug momentarily for a peek.

I did post pix about the muffler and manifold mods above. I would have to look for it, as you would.

I also posted about the oil changes, which can be messy. Just checking one of the 2 dipsticks will prob cause spillage, unless you tip the whole machine. I don't recall the thread size of the drain plug, but you can also use a rubber or plastic hose and stick it in the hole with the machine tipped, then tip it the other way with the boom to drain. I try to change every 25 hours, and use 15W40 oil.

 

[D'oh]

https://www.amazon.ca/Upgraded-Changing-High-Temperature-Replaces-1723165SM/dp/B0BW6Y9TH3/ref=pd_lpo_sccl_1/143-9441202-6130854?pd_rd_w=x1Mnq&content-id=amzn1.sym.135c60bb-68cb-4d34-ae94-a6f8d634fb42&pf_rd_p=135c60bb-68cb-4d34-ae94-a6f8d634fb42&pf_rd_r=CN2BZHA4W6QM6E0RV132&pd_rd_wg=hYUCq&pd_rd_r=a5fc9bb2-1d0d-466e-a727-815d888dd55a&pd_rd_i=B0BW6Y9TH3&psc=1

3/8ths hose will work for Oil Drainage.

 

[JohnnyB24]

I did post pix about the muffler and manifold mods above. I would have to look for it, as you would.

I also posted about the oil changes, which can be messy. Just checking one of the 2 dipsticks will prob cause spillage, unless you tip the whole machine. I don't recall the thread size of the drain plug, but you can also use a rubber or plastic hose and stick it in the hole with the machine tipped, then tip it the other way with the boom to drain. I try to change every 25 hours, and use 15W40 oil.

 

[JohnnyB24]

I did check the oil level, it was about in he middle of the stick and I bought a couple of jugs of 15w50 Mobil 1 that I plan to use after break in. At least in the summer.
What type and how much oil for my lawn mower? | Briggs & Stratton

I think your 25 hour interval is one I'll follow as well and I really like D'oh's hydraulic hose oil drain line recommendation.

I did take apart that Pilot filter and determined the element was questionable and not easily replaceable so I ordered a new assembly from Grainger.

 

[dfkrug]

I did take apart that Pilot filter and determined the element was questionable and not easily replaceable so I ordered a new assembly from Grainger.
[/QUOTE]
It does look like the filter is supposed to handle 15 microns, which is certainly better than nothing. It also seems to be one that you clean, rather than replace. Thx for posting.

A drain hose like DOH proposes is great, if you can fit it. I made something out of a pipe nipple and a small ball valve, but I could not make it fit with my ballast weights in the way.

 

[HCS-II]

I can confirm that on the 420cc Rato engine of my EM15, the oil drain plug has M12x1.5 threads so the correct hose would be the following one: https://www.amazon.com/gp/product/B0C6XMBF26

 

[JohnnyB24]

I was working on the mini this morning in the garage and I lost all house rotation and stick movement. All other functions were normal. Another symptom was that the left joystick was hard to move and seemed to have pressure on it in all directions even when the machine was off.

After staring at it for awhile with a puzzled look on my face, I took the plastic sides off the joystick to inspect the valve but everything looked ok. I had recently had the filter apart that feeds fluid to the hand control so I was worried there was a restriction on the return line somewhere and it was not letting fluid back to the tank.

While trying to figure out which hose was the return, I noticed a hose that appeared to be pinched in between the sheet metal and a frame member. I had the floor pan off recently also, and I somehow didn't notice that hose had moved in the engine compartment and it got pinched when I tightened everything up.

I released the hose and all is ok now except for a slightly pinched hose and a badly bruised ego. I learned to put a few more straps around those hoses to keep them in place.

 

[obsideus]

I'm still reading through this whole thread - we just bought the attached photo (a 2024 MIVA VA13C 1-ton) at auction, and it seems plenty powerful for our 3/4 acre yard and all the projects we have planned. But, it's almost rolled a few times. Besides putting the backfill blade down, what else has anyone done to improve stability?

 

[dfkrug]

Besides putting the backfill blade down, what else has anyone done to improve stability?

Welcome to TBN.

Yeah, these minis are tippy, and it is more top-heavy with the cabin. Yours looks like the longer track version (41 instead of 37 track drive links), and those units don't seem to have any ballast weights in the back. Adding some would help but that is a big job.

To avoid tipping over, I would suggest you don't run at wide-open throttle, until you get more used to the speed and jerkiness. You still need about 3000 RPM if running the 420cc gas engine.

The other thing to avoid, esp if on sloped ground, is not to swing the house around with a full load in the bucket when even slightly extended.

Be careful.