Importing and modifying a new mini excavator from China

[Fredrik]

I chose to purchase from Capital Automotive Equipment Ltd (CAEL

If you don't mind me asking, what was the out the door price?
Looks like a nice machine.

 

[Aaron-BC]

Congrats on the new machine, Aaron. Thx for posting. Hopefully CAEL in Ontario will step up and provide parts and technical help. Do they provide any docs, esp for the hyd system? Does it look like the hyd system on the Diggit EM15 I posted above (post #540)?
Did the company set the relief pressure correctly, as well as provide a spring-to-center AUX control?

Hey!

First, CAEL boasts a 1 yr warranty for parts only. Standard fare, no wear parts or operator error. I emailed them this morning with a test case re: a failed Hour Meter… I’ll follow up here with the results from that. They provide a digital manual for most (all) their machines other than this one! I incorrectly assumed that it was there when I took possession, and have asked for them to provide me with one.

The plumbing is very similar to the EM15 above in that it is an 8 spool gang, 4 servo and 4 direct. There is no accumulator and the pilot relief and interlock solenoid are mounted on the base of the house. Aux and Dozer are both spring to center.

The relief pressure… I am struggling to find fittings to adapt our “standard” stuff to the 24` o-ring fittings that the Chinese prefer. Getting a proper reading has not been possible yet. That being said… on both PRVs the locking nut was not even finger tight. My gut told me that the pilot system was much too high and I have lowered it considerably. The main system feels right but I look forward to testing for sure.

The return filter mod is not too bad, and much more important than the cooler. Nice to have the cooler, too, and hopefully, an hour meter.

If nothing else, the cooler plumbing gives me a head start on the filter. It should be an easy enough addition. I mention the hour meter above. Yes, one is installed center on the dash. However, the machine spent an hour in the rain last week and the meter did not survive. It is clearly not weather rated and was mounted in the worse possible location considering that. I have asked for a weather rated replacement… a good early warranty test.

Aaron.

 

[Aaron-BC]

If you don't mind me asking, what was the out the door price? Looks like a nice machine.

Thanks Fredrik, I think it is pretty nice even considering its deficiencies...

As for the final price, I'm not being coy but all I can really say is I drove out of the yard having paid less than what is listed on the CAEL website. I dealt directly with Al at the Surrey yard. He was very friendly and accommodating. They don't add extra fees to the listed price and only charge appropriate sales tax based on your situation. They will provide you with a detailed quote on anything you are interested in via email as well.

 

[dfkrug]

The relief pressure… I am struggling to find fittings to adapt our “standard” stuff to the 24` o-ring fittings that the Chinese prefer. Getting a proper reading has not been possible yet.

If you are near the big city, you may have an hydraulic shop to get fittings and adapters. Don't forget some male and female plugs, both 10, 12 mm. Or you can order them from DiscountHydraulicHose in PA. They are metric O-ring fittings.

 

[dfkrug]

The plumbing is very similar to the EM15 above in that it is an 8 spool gang, 4 servo and 4 direct. There is no accumulator and the pilot relief and interlock solenoid are mounted on the base of the house. Aux and Dozer are both spring to center.

Hmm. Does your pump look like a 2-stage pump as in the EM15? With just one outlet?

1500psi may be fine for the servo circuit, but I do not know where the test port is without a manual. You can always tee into one of the small work port servo hoses with a gauge and operate it to relief. Not as important as the main RV setting. I just use the AUX hose, like you may have seen in my video.

Does your machine kill the engine with the key switch? And the hour meter, too? Those red hi-current shutoff switches are a relic of the one-cyl diesels that had to be shut off mechanically. They killed many hour meters.

 

[Aaron-BC]

If you are near the big city, you may have an hydraulic shop to get fittings and adapters. Don't forget some male and female plugs, both 10, 12 mm. Or you can order them from DiscountHydraulicHose in PA. They are metric O-ring fittings.

Yes, they are mostly metric 24D-Cone. I think that my search for info on adapting to these things is what lead me to this thread in the first place. It is a bit of a frustration but I'll persevere. I did locate some metric cone to BPT close by LOL. Might take a few steps to get what I need. I do have a powered Crimper and a full selection of JIC, ORB and PT fittings at my disposal so if I need to do any in-line stuff I can just crimp in what I need.

Aaron

 

[Aaron-BC]

Hmm. Does your pump look like a 2-stage pump as in the EM15? With just one outlet?

Two Outlets.

The outboard one goes directly to the pilot system. That system has a pressure relief and the interlock solenoid. This means the safety interlock ONLY locks out the main implement controls... not aux or travel.

Off the truck, the hydraulics were basically uncontrollable. I have about 30 years on excavators and, even though I know what this sounds like... I'm pretty good . Running this thing made me feel and look like a rookie! I thought I just needed a bit of seat time but after a short while I realized that something was amiss. I spoke to my Finning Mechanic friend who suggested that the pilot system pressure may be set too high and was slamming open the servos. This was easy enough to test and so far made a huge improvement. I'm comfortable with Hydraulic systems, but admittedly a bit weak on the more complicated theory. I'm working with a couple pros to try to further tame this beast.

 

[Aaron-BC]

Does your machine kill the engine with the key switch? And the hour meter, too? Those red hi-current shutoff switches are a relic of the one-cyl diesels that had to be shut off mechanically. They killed many hour meters.

Yes. there is a "key" switch which activates the starter and grounds the ignition in the off position. As delivered the hour meter came on with the disconnect as opposed to only when the engine is running. It was hot (for BC) for a couple days and I found that I wanted to shut down the engine when I was off the machine but wanted to leave the cooler fan (which pulls air though the engine compartment) running but hated the meter counting that time. The key switch has two contacts for the stop/run positions but both are closed at stop so I had to use a relay in order to wire the Hour Meter to properly count run time. That was nice for a couple days til it rained.

Speaking of wiring... The wiring on this thing as delivered is horrible. Poorly planned and horribly executed. I'll post more about this soon.

 

[Aaron-BC]

Can't make this stuff up. I didn't even notice this label until the machine was loaded in the trailer and I was halfway home. Clearly I have become complacent with warning stickers.

It is easy to laugh at this, but it really made me wonder... if these machines were able to leave the factory with no one noticing this, what else was missed? I know... it's assembled by non-english speakers but c'mon... how hard would it be to have SOMEBODY proof your work?

 

[Kyle_in_Tex]

Chinglish at it's finest.

 

[dfkrug]

Speaking of wiring... The wiring on this thing as delivered is horrible. Poorly planned and horribly executed.

And to add to that, the wiring needs to be updated with the proper ignition switch that not just grounds the ignition to stop the engine, but also an AUX position for the light, the hour meter, and in your case, the hyd cutoff solenoid.

In the new wiring diagram I posted as part of this thread, the makers need to toss their starter switch, and replace it with an IGNITION switch. I just use a STENS riding mower ignition switch, and eliminate the red tee-handle cutoff switch.

Mounting the starter relay and charge regulator inside the house but not on the engine is important, too.

 

[Fredrik]

Off the truck, the hydraulics were basically uncontrollable.

Welcome to the WTF club. I too thought the language these things spoke was the same as bigger machines.

I can almost assure you more is yet to come. Please be careful.

 

[Fredrik]

Can't make this stuff up.

Translation : I't is forbidden to use machine in RANE, WATER will cause machine to melt.

 

[Aaron-BC]

Translation : I't is forbidden to use machine in RANE, WATER will cause machine to melt.

Thanks Fredrik, that's most helpful and explains my failed Hour Meter!

I can almost assure you more is yet to come. Please be careful.

I am... mostly... Thank You!

 

[Aaron-BC]

And to add to that, the wiring needs to be updated with the proper ignition switch that not just grounds the ignition to stop the engine, but also an AUX position for the light, the hour meter, and in your case, the hyd cutoff solenoid.

Thank you, yes. Adding a relay has made this part of the system usable for the time being. But- I have a list of fixes left to do and by the time I am done I don't expect much of the original wiring to remain. I will be sure to document that here but just as a teaser consider this: in nearly every case where wires are spliced or joined they have been twisted and taped. I know what I pay for crimped connectors and I assume the factory can get them much cheaper than me, so this was unexpected.

Mounting the starter relay and charge regulator inside the house but not on the engine is important, too.

This is a great point that I did not think of, Thank you.

Aaron

 

[dfkrug]

Off the truck, the hydraulics were basically uncontrollable. I have about 30 years on excavators and, even though I know what this sounds like... I'm pretty good . Running this thing made me feel and look like a rookie! I thought I just needed a bit of seat time but after a short while I realized that something was amiss. I spoke to my Finning Mechanic friend who suggested that the pilot system pressure may be set too high and was slamming open the servos.

Modern multi-pump pilot-controlled hydraulic machines are wonderful to operate. Every time I get a chance to operate one, it is a pleasure.

Don't feel too bad if you felt like a rookie. One-pump systems are a somewhat different skill, as well as 4-stick (non-joystick) direct-acting one-pump systems. The latter type was how I started, back in the 90s.

I think your guy may be correct about the servos on your machine. They operate somewhat smoother than the other direct-acting 1-tons because the 1/4" hoses add some delays and cushioning to the movement of the actuator spools. If the flow or pressure is too high, you will lose some of that. Some of these pilot controls call for only 500 psi or so of pressure. So far, I have no idea what the spec is for these tiny valves in this application. I suppose that if you adjust it too low, you would have unacceptable delays, esp without an accumulator.

 

[dfkrug]

View attachment 813794View attachment 813795
Two Outlets.

The outboard one goes directly to the pilot system.

One more thing about your 2-pump system.

It looks like each chamber is about the same size, which would deliver very large volume to the servo system. That would mean that your servo system pressure should be pretty low, maybe as low as 500psi, in order not to deliver too much power to the actuators.

I suspect that is why the Diggit's servo system uses a flow divider, which could be set up to have a much lower flow rate to the servos, vs. the main valves.

Some pumps have a label on them with the flow rate stamped on it. Single stage pumps for these machines are usually about 6.5-6.8 cc/rev.

 

[ptsg]

One more thing about your 2-pump system.

It looks like each chamber is about the same size, which would deliver very large volume to the servo system. That would mean that your servo system pressure should be pretty low, maybe as low as 500psi, in order not to deliver too much power to the actuators.

I suspect that is why the Diggit's servo system uses a flow divider, which could be set up to have a much lower flow rate to the servos, vs. the main valves.

Some pumps have a label on them with the flow rate stamped on it. Single stage pumps for these machines are usually about 6.5-6.8 cc/rev.

While the physical size of each section looks the same, the internal gears can be narrower for the pump of the pilot circuit. It's not uncommon for pump manufacturers do this, so they don't have to machine different length bodies for each pump size.

 

[dfkrug]

While the physical size of each section looks the same, the internal gears can be narrower for the pump of the pilot circuit. It's not uncommon for pump manufacturers do this, so they don't have to machine different length bodies for each pump size.

Yes, that is possible, and that is why finding and reading the label is important. Or taking it apart to see.

On the spare downsized pump we ordered from the maker (HeChuang), I took it apart to measure the volume, since there was no label.

BTW, component quality has been generally good, tho documentation, awful.

 

[Aaron-BC]

Some of these pilot controls call for only 500 psi or so of pressure. So far, I have no idea what the spec is for these tiny valves in this application. I suppose that if you adjust it too low, you would have unacceptable delays, esp without an accumulator.

It looks like each chamber is about the same size, which would deliver very large volume to the servo system. That would mean that your servo system pressure should be pretty low, maybe as low as 500psi, in order not to deliver too much power to the actuators.

Yes, in my conversation with my Finning-Friend he suggested that the required pilot pressure could be quite low. He was clearly doing a lot of guessing at the time, but he seemed to think it could go well under 500psi. He saw no serious harm coming from lowering the relief as a test as long as I didn't back the adjuster right out. I'm still trying to cobble together a method for actually getting a reading off this.

While the physical size of each section looks the same, the internal gears can be narrower for the pump of the pilot circuit. It's not uncommon for pump manufacturers do this, so they don't have to machine different length bodies for each pump size.

Yes, that is possible, and that is why finding and reading the label is important. Or taking it apart to see.

Thanks guys. I am working with my guy @ CAEL to get a manual or at least the proper component specs. The pump has a laser etched label which I'll attach here. I have yet to find product spec sheet. (admittedly, I have not yet looked very hard). If MPa = megapascal then I assume 3600 +/- PSI @ 1000RPM (?) But... flow?