PBY Power Beyond & Detent Valve question

[J_J]

You need PB operation downstream flow to another valve. The only way to get that is with a valve with a PB port. The PB port is necessary to feed the 3pt system. If you are talking about a log splitter valve, those valves are not designed to have a high back pressure. The PB port will handle full system pressure. If you have a standard log splitter valve in series with the 3pt, I would not lift a large load with the 3pt, as it may develop high pressure, and might affect the seals in the log splitter valve.

The only log splitter valve with PB that I know, is the double lever log splitter valve by Prince. Not cheap either.

The OUT flow or RETURN flow on a hyd valve is normally used to pass on the expended fluid from the cyl's, and is not designed for high pressure. Thus the reason for PB.

 

[J_J]

this is the spool i used
https://www.surpluscenter.com/item.asp?item=9-1262&catname=hydraulic

i have it on my splitter and it has worked fine. it has detent for raising the cyllinder.

it just allows the hyd fluid to pass tight on thru it until i move the lever, then it bypasses the fluid to my cyllinder. its for double acting cyllinder, and its $70.00

im not too sure what you bean by the 5th port saying PBY??

the valve doesn't need a power beyond port. its a open center valve, so the fluid just passes thru unless you move the handle. are you sure this isnt supposed to be the pressure release adjustment??? for the detent

The PRV for your log splitter valve is by the handle, the large hex nut. The small hex bolt at the rear of the splitter valve is to adjust the detent pressure.

 

[thallman]

You need PB operation downstream flow to another valve. The only way to get that is with a valve with a PB port. The PB port is necessary to feed the 3pt system. If you are talking about a log splitter valve, those valves are not designed to have a high back pressure. The PB port will handle full system pressure. If you have a standard log splitter valve in series with the 3pt, I would not lift a large load with the 3pt, as it may develop high pressure, and might affect the seals in the log splitter valve.

The OUT flow or RETURN flow on a hyd valve is normally used to pass on the expended fluid from the cyl's, and is not designed for high pressure. Thus the reason for PB.

So, J_J if I am hearing your correctly to PBY port on the valve is the actual port resposible for continueing the flow of the hydraulic circuit when the valve is in nuetral? And thus, the "OUT" on the valve simply dumps the remaining fluid from the cyclinder (log splitter) back into the reservior?

Makes since.

So how do these folks with yanmar run a pressure detent on their log splitter when using a PBY valve run of the divider block? Are they using two valves. One valve on the splitter connected to the PBY valve? How then do you continue flow to the splitter, zip-tie the first valve handle when in use? That seems off.

 

[winston1]

My front end loader has a joystick control valve. Only has in and out. No power beyond. Pressured steel tubing line is cut from pump going into loader valve, out of loader valve and back in to pressure line. This pressure line goes on to the 3 point control valve. This is the same thing you are talking about. Don't know what your 336 hydraulic pressure relieves at but compare it with what the splitter valve is rated for. If it is in the ball park I can't see blowing seals out of it with back pressure. Sure haven't blown them out on my loader valve. This is just my opinion. I have read several posts by J_J and he seems to be the hydraulic guru so probably be best to listen to him. I don't mean that to sound smarty.

 

[normde2001]

Sounds to me like you are way over-complicating the issue. I would use the detented valve that you ordered, along with Hoye's install suggestion and be splitting wood by lunchtime.

 

[thallman]

Thanks, but I really don't want to cut into the high pressure line. I feel like the diverter block is there for a reason with ports for a reason so why not use those.

 

[J_J]

thallman,

You said: So how do these folks with yanmar run a pressure detent on their log splitter when using a PBY valve run of the divider block? Are they using two valves. One valve on the splitter connected to the PBY valve? How then do you continue flow to the splitter, zip-tie the first valve handle when in use? That seems off.


That is exactly how they do it.

I believe that just about any valve manufacture will tell you that the OUT port on a valve should go to tank/reservoir.

I have tried out unusual situations before also, and some of them work and some did not. It depends on the factors involved.

I think the fact that you don't see anything about valves being destroyed, is because few people will not broadcast their mistakes.

Taking a chance is just that, It may work for a year, and then blow. At least, you got a years worth of work out of it.

I am only trying to advise here, but do what you have to do.

Maybe you don't know this, but pressure is the result of resistance to the flow of hyd fluid.

High pressure does not belong in a low pressure situation.

Most log splitter valves are built with high pressure in, and low pressure out.

 

[J_J]

Sounds to me like you are way over-complicating the issue. I would use the detented valve that you ordered, along with Hoye's install suggestion and be splitting wood by lunchtime.

He already has a high pressure outlet for the BH.

 

[normde2001]

Thanks, but I really don't want to cut into the high pressure line. I feel like the diverter block is there for a reason with ports for a reason so why not use those.

If cutting the line is what you are stuck on, apparently you didn't read the whole Hoye write-up. The only PBY hookups I have heard of involve routing PBY into the transmission dipstick hole, which makes for a really messy installation. Maybe the 336 has a better solution.

 

[thallman]

Yes, the 336 is "better"...maybe! See the attached service manual pages in the previous posts. What stinks is having to buy two valve ($$) but I guess it's the best thing. I also hate having so many hoses running around (more for me to break ) Also, I'm having a hard time finding the correct fittings. (UNF) Specifically speaking a 3/4-16 UNF elbow with the appropriate size O-ring. Any suggesting there? I guess any 3/4-16 UNF to NPT adapter would be better since NPT seems to be so readily avaliable.

Thanks,
Thomas