Rc4wd excavator valve question

[chris deacon]

When you say a PVR valve i presume you mean a Pressure reducing valve? You will need a way to control this valve. Why do you want to get rid of the 4th valve may i ask?
Im not sure if you know how the 4th valve works on the 4200xl?
It opens when none of the hydraulics are being used to allow the oil thats not being used to go back to the tank. Then every time you use a hydraulic the 4th valve will close so all the oil can be used to move the rams. This 4th valve allows the pump and motor to last a lot longer. I might be telling you how to suck eggs here but i just thought i better make sure you understand what it is doing?

[rccrazy523]

Chris, thank you for your help.
The reason I was going to remove the 4th. valve is, I was thinking about mixing the channels to operate the pump only when needed.
Is this a better setup? Or, do you think I should leave the 4th. valve?
I see a lot of excavators running this setup with no 4th. valve.
THANK YOU AGAIN FOR YOUR HELP

[chris deacon]

Well the way i see thing is stopping and starting a motor will only make the motor wear out quicker? Also you have to think about how long it takes for the motor to spool up every time you operate a ram. Personally i think that a 4th valve is a brilliant idea and i dont see why other companies have not employed the same method?

[Lil Giants]

Originally Posted by chris deacon

Well the way i see thing is stopping and starting a motor will only make the motor wear out quicker?

It's not the motor, it's the esc that will fail. And being Chinese electronics, there's no thermal protection built into the esc, so when the esc overheats to it's melting point there will either be just a puff of smoke when the esc burns out or it will catch fire... no shyt! I've heard it happened to several guys with the Chinese dump trks. that hyd pump motor runs from a dead stop.

Personally i think that a 4th valve is a brilliant idea and i dont see why other companies have not employed the same method?

It's b/c Eagle Machinery company is retarded, they're using a motor that's much too large for it's application... their solution is to dial back EPA to 19% instead building or buying out of country a properly spec'd motor.

Something else, the PRV that's in these Chinese models, the coiled spring is much too stiff & with the barrel so short - not a lot room in the 1st place for a proper length coil to allow the BB to move to relieve pressure & allow flow. Throw that piece of crap away & make your own with a longer barrel for a lighter spring so you can get a much finer tuned pressure setting & that 4th valve wouldn't be needed.

[fhhhstix]

Originally Posted by Lil Giants

Something else, the PRV that's in these Chinese models, the coiled spring is much too stiff & with the barrel so short - not a lot room in the 1st place for a proper length coil to allow the BB to move to relieve pressure & allow flow. Throw that piece of crap away & make your own with a longer barrel for a lighter spring so you can get a much finer tuned pressure setting & that 4th valve wouldn't be needed.

That is a fact and mine came with a plunger inside the barrel and the finish was horrid so I tuned them both up with some polishing so the oring on the plunger would allow it to move easier. I also adjusted the spring. I found out quickly something was wrong when I could not maintain a steady psi each time I demanded psi.


The forth valve is similar in function to a CAT hyd system. Don’t change the speed of the motor or pump but adjust the flow going to the valves. Where it differs is the real machines do this with dual variable pumps and the model does it with a dump valve not exactly the same thing but still the same result.

Replacing the junk motor would help a bunch I have found that it will lock up due to its poor tolerances and that alone makes it hard to start without a load. A gear reducted motor would be a big improvement the motor spins way faster than the pump can use so slow and more starting power would be a help. The vario uses a belt drive with a smaller cog on the motor and a bigger cog on the pump hence the gear reduction slow it down and utilize the power spent to operate the pump

[elvis65]

a little racist I think.

[Cooper]

Originally Posted by elvis65

a little racist I think.

Let's not be hyper critical and bring all the b.s. Politically correctness into this hobby, it is simply a reference to the whole world business machine, don't read a book about it, buy a cheep machine and also buy a high quality machine and educate yourself. There is a difference between cheep, inexpensive, low quality, high quality, and expensive. Economics 101- no such thing as a free lunch!!

Please delete if offensive, I just don't want to be politically correct and worry about hurting someone's feelings, that is too much like work and this hobby is as far away from that as I can get

[uktwin]

Originally Posted by Cooper

Let's not be hyper critical and bring all the b.s. Politically correctness into this hobby, it is simply a reference to the whole world business machine, don't read a book about it, buy a cheep machine and also buy a high quality machine and educate yourself. There is a difference between cheep, inexpensive, low quality, high quality, and expensive. Economics 101- no such thing as a free lunch!!

Please delete if offensive, I just don't want to be politically correct and worry about hurting someone's feelings, that is too much like work and this hobby is as far away from that as I can get

Its not racist at all,, its a fact, 40 years ago Japanese motor bikes were the same, made out of monkey metal, put a spanner to it and it crumbled, still good enough to see off our(British) motor cycle industry but then they thought having a vertically spilt crankcase was a good idea to keep oil in., you get what you pay for in any engineering and the longer you do it the more you realise that, this why its so hard to get any plans of machines as OEM's are afraid cheap Chinese parts are put into their machines, damaging their reputation, Aviation and F1 are paranoid about it.

regards
Kevin.

[elvis65]

ok

[Lil Giants]

Originally Posted by elvis65

a little racist I think.

I changed it... better? I have no personal resentment to the Chinese ppl or any other ethnicity on this planet.

China mentally in manufacturing on the other hand from my viewpoint, they're all about production & couldn't care less about quality, just get it out the door, sell it cheaper than anyone else can & sell lots!

[elvis65]

Hi
I totally agree, for a couple of dollars more in the production costs and a little more time they could produce some hi quality stuff.
but it's just that will do mentality and sod the quality that will always let things down.
dave