Adding QC and aux hydros on a Cat?

322C. Just trying to get an idea if this is even feasible? Are the valve blocks usually already built for this? Or is this sort of a deal that if they weren't kitted at the factory or dealer, it would become a huge task?

I think if you post your serial # one of the guys with access to SIS can tell you what your unit does and does not have

Damnit, I forgot to get that.... Will do! Were the the valve blocks built with and without aux outputs?

nothing more than a guess I will say you should have 1 aux valve section on the machine available if you have no additional plumbing on that machine. Look at the control valve and see if you have one not used Or looks blanked off. RH valve bank section towards the center ?

I sent the serial to Nige for SIS Intel but I did grab a pic and appears there is in fact a spare hydro. What are the options for piping? I can only guess how much cat wants for a few pipes.

fastline said:

I sent the serial to Nige for SIS Intel but

Click to expand...

if you don't want our help why bother posting

HEX prefix Mark.

I am not playing faves and happy to send to anyone else, I just didn't want my serial blasted over the net. It does appear to have the section B, but I am not sure if that is a double acting spool. Would need to gather info specifically on the MCV I guess? Or is that a pretty typical thumb circuit?

It will work just fine for a thumb. Talk to your dealer about kits. Way easier unless you plan on figuring out the electric over hyd pilot side, followed by all the main lines and 2 valve reliefs all while this has been done hundreds of times and all the info is set up.

Electric over hydraulic would be news to me.
And in thought the relief was built into the mcv?

E/H is how you press a button on the joystick and that turns into oil being sent to the valve spool.
That’s the main relief. You need line reliefs as your thumb is half or less pressure than the main or you will wreck things quickly. Again this is why the dealer engineered kits are usually better to pursue.

When I was considering adding aux hydros to our 321DL I was going to order from here -

http://www.hkx.com/

Turns out our local Cat dealer buys and installs kits from them since they are cheaper than OEM.

The extra spool section has plugs where you can install OEM port relief valves with makeup checks, that would be like the cartridges you see sticking up on the two sections to the left of the unused section. The reliefs dump to the tank return, so will work just fine for any double acting cylinder application.

Thanks, I figured the mcv would have most of this configured. I probably need to chase down some proper hydro schematics. I do realize I can just "buy a kit", but I am just a guy that wants to know how everything works. It can be handy in the field at times.

From the talk above, it sounds like the thumbs don't run at full system pressure? Is this more of a fail safe to protect other components, especially the structure of the stick?

As to the control, I am not yet sure where the pilot system is typically tapped, but I might like some input on either the contact switch on a stick, or a direct pilot foot pedal. I guess I could probably find a servo foot pedal so I don't need to run lines in the cab, but not sure what is typical. Honestly been too long since I ran a thumb machine to even recall how it operated.

even though I typically hate foot controls, I might lean that way so I can modulate the thumb movement while running the bucket. Don't know but maybe it works just as good with a stick switch but you only have one speed there.

You can use a thumb roller on a joystick handle to give you full variable, but then you have to have a proportional pilot valve and the electronic driver for it. Again, kits are probably available, LOL. I think typically thumb cylinders may have a lower pressure rating than the OEM ones, YMMV. In any case you NEED port reliefs because without them once the spool is in neutral the cylinder is hydro locked and there's nowhere for oil to go when the bucket curls back against the thumb. If you push hard enough you find out which component is weakest, hose, steel line, cylinder tube, or in some cases you get lucky and only bend the cylinder rod.

Oh yes, I certainly understand the importance of relief and I guess was not thinking. Been probably 5-6yrs since I got deep in hydro stuff.

So the cat relief is a relief and make up in one or did I misread? I am just really curious of the porting! I guess I could dig up some schematics on the last hoe but it was older.

fastline said:

Oh yes, I certainly understand the importance of relief and I guess was not thinking. Been probably 5-6yrs since I got deep in hydro stuff.

So the cat relief is a relief and make up in one or did I misread? I am just really curious of the porting! I guess I could dig up some schematics on the last hoe but it was older.

Click to expand...

Should be yes, just a check valve built into it so if one side goes across relief, the other side can suck oil from the tank galley. Can't swear to it but I've never seen one on an excavator that wasn't.