Detent valve problem

can you post a few pics?
not sure I can help, but someone might

So far it sounds like most things are working right. First there should be no pressure until there is resistance, which should only be at the end of the stroke in or out and when actually splitting wood. If the valve is not kicking out at the end of the .return stroke then the work ports on the valve are reversed. The 500 pounds is normally where the detent will kick out.

Normally you would want the valve handle to move in the direction the ram is moving. On an Energy brand valve the pivot point can be changed to reverse the operation of the handle. There are 2 screws that hold the pivot to the front of the valve . Remove the handle , then remove the 2 screws , rotate the pivot a half turn and reinstall the screws. I drew pics hope it explans what I have written.

First, kudos to you for having a pressure gauge in the circuit, it’s the first step in diagnosis.

Q not getting enough pressure? Q

Second, restating triptests post, pressure is a result of load, so there won’t be pressure until it hits end of stroke, or wood. Pumps just move oil and make flow. Load resistance creates pressure. If the oil goes back to tank easily, it won’t develop resistance, so that doesn’t mean which particular component is bad. We still have to find the path the oil is going.

If the engine is only slowing slightly, that tells me full flow at 600 psi seems right.

You could plug off the cylinder hoses to eliminate the cylinder seals, and check the RV setting. I doubt the seals suddenly failed enough to pass 11 gpm at 600 psi, and you said another spool valve and RV does the same thing. I don’t think either cylinder or RV are the issue.

The cylinder should be retracting with the spool is pushed into the valve, sticking out the back end into the detent balls and grooves. Can’t just reverse hoses or the detent may be on the wrong direction.

When you say new 11 gpm pump, meaning somewhat recent, or is it the first startup for this pump? In other words, did this machine work fine before disassembling the valve for detent repairs or seals?

Is the spool reversible end for end? Some have threads on both ends, most cheaper valves do not, the handle connection is integral to the spool for cost reasons. That could have affected function if spool is reversed.

Most likely, the check in the pump is not working right. That’s my bet if this is the first startup of a new pump. 500-600 is usually where the pump unloads the large stage, so that may be a clue.

The small stage is always connected to the outlet port. This is the slow speed, high pressure. Large stage goes through a check valve and joins the flow from the small stage and out. When they are both added together you get high speed, but not enough engine hp to turn against high pressure.

On the large stage outlet, but before the check, is the unloading valve that can ‘unload’ the output of the large stage back around to suction port at say 50 psi. It gets its pilot signal from the outlet port on the other side of the check, and only unloads the big stage when the outlet is say 600 psi. The check is to prevent the small stage oil coming backwards and unloading everything at 600 psi.

I think the check valve has failed, and both sections essentially unload back to tank at a pressure lower than enough to operate the detent to release. i.e. if it detents at 800 psi, but never reaches that point, then the detent may be just fine it just never gets enough pressure to work.

Wish I could post a schematic. I will try later

If this is a new pump from vendor, don’t disturb or they may squawk about warranty. Take it back. If not, take the unloading cartridge out and look for clues.

kcj

I have a schemaitc, pasted into word, but can't paste in here. Also can't attach it as it is not an image file.
How did you insert the sketch above?

tks, kcj

kevin j said:

I have a schemaitc, pasted into word, but can't paste in here. Also can't attach it as it is not an image file.
How did you insert the sketch above?

tks, kcj

Click to expand...

I scanned the pic .Then "save as" in my pics .When adding to a post I go browse attachments to open pics. At least I think that is how I did it. I not real old but I'm only a grade school-er when it comes to this computer stuff.

tried that, but scanner at work sends to me as pdf or tiff, neither will attach or insert in.
have to talk to my middle sone I guess.

I am about 5th grade level computers....

kcj

Jimmy Shine ,
Did you get that pump off E-bay. I have bought several off E-bay and have found that some of them seem to be factory rejects . Some pumps could not meet factory specs and one had a loose suction tube.

Good info.
a. that fact that the pump is new and never worked before means it is likely the pump. If it had been worked before, and suddenly not working when only the valve was disturbed, would make it less likely.

b. the adjustment screw is the unloading setting. Basically, it is set to run both stages (max flow and speed) up as high pressure as possible until it runs out of engine hp. Then the large stage unloads to tank as I wrote above. Once you gt it working, you set it just that way: keep increasing the pressure setting until it bogs the engine just before unloading, then back off. Note: must be in resistance into the wood, and it may happen very quickly. Or, if the wood splits at below 800 psi, it may never unload and slow down. That is a good thing, you want as much speed as possible with as much pressure capability as possible.

c. It is not as though you are ‘not getting second stage’ because it doesn’t change from one to another, or turn off one and turn on the other. Both are added together for high speed, then the large section is unloaded. The small section that you see as ‘second stage’ was there all the time.

The fact that pressure increases with the unloading adjustment screw means that portion is working fine. I’ve just doubled my money down on the gamble that the check valve is not working, or maybe even missing entirely. since this is a new unused pump. I don’t have a cutaway, nor a pump at hand to check it, or I could figure it out on a glance.

My suggestion, pull the unloader cartridge out, careful not to cut the o-rings around the cartridge but it will come out like a spark plug. See what else is in there. Maybe you have to split the pump. Should be easy enough. My guess how I THINK it is built will be there is a ball and spring that works as the check valve. Follow the outlet port of the larger (wider) gear set. That is the large stage. Before that oil gets to the outlet port of the pump casting to the outside world, it should pass through this check. The unloading valve and the pilot signal from the small gear set will go off to the side somewhere, but the main flow from the large gear set must pass through a check. If it’s an open path, bingo, no check. If the spring is missing, or ball broken, etc. same story.

Haldex Barnes will have parts, but a precision bearing ball from an industrial supply house will work, as a standard round steel ball is what it is and they purchase it from the bearing industry. I am saying ball for check because it is the cheapest way to accomplish so that is what I assume they will have done. It could be a tapered cylinder shaped hollow poppet with the spring inside it, but my bet is on simple ball and seat.

And I will try again to post a schematic, but have no access to actual cutaways or pictures.

Trip, good point. I need a 13 gpm preferred or maybe 11 for another project. Many of the ones I have watched on ebay state they are new old stock, or purchased in large lot from vendor returns or obsoletes, some have Northern numbers form the 1980’s. Not sure what you are getting, and they sell within $20 of new price. One sold for $9 more then the new price listed in the same ad that is sold from! I don’t get it. If I can’t get it for half price, I’ll buy a new one exactly what I want from Surpluscenter. Home project is different, but can’t take a risk of poor quality for a customer project.

Anyway, take it apart and look for missing or malfunctioning check.
BTW, when set up to unload at 800 psi, did the detent valve work?

k

Great you found it, and thanks for followup on the cause.
Looks like I lost my money betting on the check valve-I thought you had already checked the drive shaft, but was confusing this post with another one.
This post below has a good schematic of how a 2 stage pump works, similar to what I was trying to add.

http://forums.hydraulicspneumatics.com/eve/forums/a/tpc/f/8621030121/m/4591051072

As you will see in the HP post, the key to diagnosis of such a simple system is having a pressure gauge reading. Look at all the stuff this guy has done, including a different engine apparently, because doesn't have data or put in a gauge....

k

Triptester, thanks for the tip on changing that valve around. It has always bugged me that i had to move the handle the opposite of the way I wanted the cylinder to move. Thanks to you, problem gone.