hydraulic oil getting hot after new valve bank and relief valve installed

[quietrangr]

I'm confused. I know that you guys know what you're talking about, but I'm simple, so if the CC system doesn't need RV, do you mean that the individual valves need RV, but not the system as a whole?

 

[Tx Jim]

If a closed center control valve has a relief valve on pressure side before spool then RV must be set at or above system pressure but if RV is located on operating side of spool(leading to hyd function such as a cylinder) then RV could be set at lower psi than system pressure. Clear as MUD

I going to post this simple test again:

Simple test on CC hyd system is remove hyd valve bank return hose from tractor,with all control levers of valve bodies in ""neutral"" start engine and if oil comes out return hose then either control valve or relief valve in valve body is at fault IE leaking causing heat.

 

[quietrangr]

TxJim, I'll try that test taking off the return line of the swing control to see if oil comes out in neutral position. But my other question is whether I could use the relief valves in the monoblocks rather than putting RVs in the feed lines after the valve bank. Cross said to install the CC kit, which consisted of a PB plug, and a no relief plug to replace the relief valves in the monoblocks. Could I just put the original adjustable relief valves back in the monoblocks? Or would that still generate heat?

 

[Tx Jim]

1st off a CC kit IMHO should not contain a PB plug but rather a CC plug. Notice the difference in the 2 plugs in the photo. An adjustable relief valve in pressure inlet won't be of any help if it can't be set at or above stand-by pressure for a CC system.

 

[CJONE]

When you say monoblocks, you mean the hydraulic control valves correct. I have not seen a monoblock valvebank have a WORKPORT relief, that is why they use sectional valves. These have places [tall sections] where you can add work port reliefs, anti cavitation valves and the like as required by the circuit. Once you add all these valve to a monoblock control valve it usually cost more money than the correct valve would have to begin with. A monoblock usually only have a main relief in the inlet or main feed line. These reliefs need to be in the work lines to the cylinders to limit force. These work lines are not used unless you pull or push the handles. So they have no effect on heat unless you run around with the valve actuated. CJ

 

[quietrangr]

OK, I think I get it now. I'm learning a lot, so much that I'm thinking I should put the old original valve bank back in it. The new valves didn't change anything with the swing function, anyway. That's not the first time I called the CC plug by the wrong name, TxJim. It's a CC plug that goes in the PB port, confusing for a slow guy like me. So CJONE, it looks like my idea to put the RVs back into the monoblock valves won't work, it would be the same problem I had before with the RV restricting and heating up the oil.

Just noticed your list of saws, CJONE. I have run all of them except the 338, no I never ran a 390, but 394s. I'm now down to a 261 Stihl because of arthritis in my wrists. (261 is roughly equivalent to a 346.) I have an old 346 as a backup saw.

 

[CJONE]

OK, I think I get it now. I'm learning a lot, so much that I'm thinking I should put the old original valve bank back in it. The new valves didn't change anything with the swing function, anyway. That's not the first time I called the CC plug by the wrong name, TxJim. It's a CC plug that goes in the PB port, confusing for a slow guy like me. So CJONE, it looks like my idea to put the RVs back into the monoblock valves won't work, it would be the same problem I had before with the RV restricting and heating up the oil.

Just noticed your list of saws, CJONE. I have run all of them except the 338, no I never ran a 390, but 394s. I'm now down to a 261 Stihl because of arthritis in my wrists. (261 is roughly equivalent to a 346.) I have an old 346 as a backup saw.

The relief valve have to be in the work lines to the cylinders. The main reliefs on the valve bank have to be adjusted ABOVE the comp pressure of the pump. In your case like you stated is 2200psi. Any of these valve IN the block are MAIN reliefs. The heat is not a result of restriction but a result of dumping oil over the relief without doing any work. Horsepower has to go somewhere and without doing work it will be generating heat. That is a simple explanation but that is all I am good for! As far as saws, the 338 is gone. I use the 346 in place of it. Ran a 261 and that would be the only stihl I would buy new. I have a 034super a 036 and a tophandle that needs to be shot. I sold my 395 to get the 390 just because I fall, buck and limb with the same saw and the 390 is a lot less work. I don't see timber all too often that a 395 is needed around here. I also have a 562 that will be replaced with a 372 as soon as I find one. CJ