Importing and modifying a new mini excavator from China

[dfkrug]

So I am still looking for a Cylinder (closed @ 14"s) and Hoses to the Aux which I think are JIC thread. Do I need the Lock Out valve seen on some thumbs?

When making my hyd thumb, I cut off the mechanical thumb brackets cuz they were not in optimal locations for a hydraulic unit.

No special valving or RV is required if you match up the cylinder diameters with the bucket cyl. I just used a spare bkt cyl. You DO need to convert the AUX valve from detented to spring-centered. See above.

Can't live without my hyd thumb.

 

[dfkrug]

I have a friend with a Komatsu pc09 and if you operate it smooth the hydraulics are smooth. So I don't buy that the all machines run like a 5k-7k chinese unit.

Well, that is not what was stated.

I have not operated a PC09, but there are lots of Utube vids of that name-brand mini. Operating it can be quite jerky as all light-weight units can be. Experienced operators will discover that they can be smoother if they don't run at max engine speed, they feather multiple levers simultaneously, and they don't let the boom or dipper cyls hit the ends of travel.

The multi-cyl diesel engines are happiest when operated at 2000 RPM or so. The 420cc gasoline single-cyls don't make rated power until 3000RPM or more. 3000 RPM is optimum in that case. The PC09 has a 2-cyl diesel. Most of these diesel 1-tons use 3-cyl 700cc+ engines, which are very smooth and torquey at 2000 RPM. THAT is why a smaller displacement pump is so important for smooth operation of gas-powered units running at 3000RPM.

I also have no doubts that the name-brand units costing $25K+ have high quality valves that can help some with smoothness.

 

[D'oh]

When making my hyd thumb, I cut off the mechanical thumb brackets cuz they were not in optimal locations for a hydraulic unit.

No special valving or RV is required if you match up the cylinder diameters with the bucket cyl. I just used a spare bkt cyl. You DO need to convert the AUX valve from detented to spring-centered. See above.

Can't live without my hyd thumb.

Pick your brain 1 more time?

The Aux Ports, I assume are JIC fittings or are they JIS? Looks like JIS is common in Japan, tough to see 30 vs 37 degrees. If it is JIS, what size? because JIC looks like 3/8"

 

[dfkrug]

The Aux Ports, I assume are JIC fittings or are they JIS?

They are neither. All 3 "brands" of Chinese excavators I have owned or seen up close use metric O-ring fittings, except on the pump.

 

[D'oh]

Just ran into another issue while using it yesterday to prep a driveway extentsion.

Briggs & Stratton EPA Fuel Cap, not venting Amazing the pressure it could hold back, and the gas would actually boil in the tank. These little Hoes get hot in the engine bay.

I have made an exhaust extension to outside, but an incoming airduct might be needed, it is still under 40F here, so operating at 70-90F will be an issue.

Wrapping the Exhaust is next on my list of To Do's

 

[dfkrug]

Wrapping the Exhaust is next on my list of To Do's

I did wrap my homemade exhaust manifold, and it did make for interesting smells for the next 60-80 hours or so.

I used a generic screw-on muffler, but I am considering a change to a quieter screw-on muffler like you see on the 420cc gas generators. I expect they are much quieter. If I do it, I will post pix here.

 

[Dragnet]

Looking into a cooling fan for this mini. Found a small 12v, but it's 6.6amp. I can't imagine this stator running a 6.6 amp cooling fan. Anyone found a better option for cooling these little 13.5 B&S XRs?

 

[dfkrug]

Looking into a cooling fan for this mini. Found a small 12v, but it's 6.6amp. I can't imagine this stator running a 6.6 amp cooling fan. Anyone found a better option for cooling these little 13.5 B&S XRs?

My LCT 420cc motor has only one charge coil, so charging current is very limited. I installed a small 12V-1amp chassis fan, which has a small draw, but does not move a lot of air.

The main cooling is done by the flywheel fan, and that was ducted to the outside in the original 1-cyl Koop and ChangChai diesels. I used the same ducting for my gasoline engine conversion. None of the Chinese makers seem to do that with the Briggs. Just as they don't upgrade the electrical system to gas from diesel.

Oh yeah, the B&S 420 and Honda GX390 both have 2 charge coils, according to specs and in the ones I have opened up. Not on all engines, of course. Your B&S may indeed have 2, so may be good for running a 7A fan. You can check with an ammeter.

 

[ArlyA]

My LCT 420cc motor has only one charge coil, so charging current is very limited. I installed a small 12V-1amp chassis fan, which has a small draw, but does not move a lot of air.

The main cooling is done by the flywheel fan, and that was ducted to the outside in the original 1-cyl Koop and ChangChai diesels. I used the same ducting for my gasoline engine conversion. None of the Chinese makers seem to do that with the Briggs. Just as they don't upgrade the electrical system to gas from diesel.

Oh yeah, the B&S 420 and Honda GX390 both have 2 charge coils, according to specs and in the ones I have opened up. Not on all engines, of course. Your B&S may indeed have 2, so may be good for running a 7A fan. You can check with an ammeter.

Aren't there fan motor's that are wound* different and take less amps??

*can't spell the correct word....

 

[dfkrug]

Aren't there fan motor's that are wound* different and take less amps??

12V cooling fans are made for electronics, or automotive use, mostly. The size and amperage of the motors used are all over the map. Electronics use, usually 0.1 to 1A or so. Automotive use is much higher, sometimes over 10A.

I see a lot of good candidates for auto use on eBay. Smaller ones of 6-8" diameter, but they do not always tell you what the amperage is. More amps means more power, and more air flow.