Rc4wd excavator valve question

[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