Prince auto cycle valve

mjeselskis · May 03, 2018, 05:42:48 PM

Has anyone had issues with the detents on these auto cycle valves? The detent on the extend stroke kicks out at almost no force and the detent on the return stroke doesn't like to release when it's fully retracted. It worked fine when new, and only has about 10 cords through it.

hedgerow · May 03, 2018, 06:19:36 PM

I have one on a homemade firewood processor also and it has about the same amount of run time as you do. Mine worked great when it was new and I never had to adjust any of the pressures.n
Now when the oil is warmed up the handles don't feel right like a o ring is hanging up. Mine doesn't like to release and let the cylinder return. I haven't been able to work on it as some health issues has me tied up. I am wishing now I wouldn't spent the money on one and just bought a detent return valve. I have read good and bad about them.

Mapleman · May 03, 2018, 07:32:30 PM

I've had very good luck with the Prince auto cycle valve on my splitter. The detents are adjustable. I've probably put 1000 cords through that splitter over the years and might have adjusted the detents 5 or 6 times. Yours being somewhat new, I'd guess that now that they're broken in, if you make the adjustments you'd be good for a long time.

mjeselskis · May 03, 2018, 08:08:14 PM

Thanks. Did you put a pressure gauge on it when you adjusted the detents or just go by feel?

I can understand how a detent being to light could kick it out early, but I still don't understand how it doesn't kick out when fully retracted. I'm wondering if the relief is set lower than the retract detent so it's not getting enough pressure to kick out.

Mapleman · May 04, 2018, 07:15:25 AM

I didn't use a pressure gauge, just made small changes until it worked right. I think you're right, if the detent is set too tight it might not release before the relief valve kicks in.

jmur1 · May 04, 2018, 11:51:06 AM

I have found the temperature (both outside air and hydraulic oil) have a large affect on my kick out operation.
I suppose the heat changes the viscosity and therefore the pressure build. Also the two stage pump may make the pressure adjustment difficult since the flow is always changing so much.

I can use mine for a good hour or so before the kickout stops working in the summer and two or three hours in the cold winter.

I noticed the oil being topped up was good so the heat takes longer to build.

Also there may be an option to use slightly different viscosity of hydraulic oil to raise or lower the oil pressure/heat (make sure the range is within the pumps range).

The kickout relief pressure adjustment is very easy to tweek once the system is up to operating temp using the relief valve (I think the detent is preset on these but check the manual for yours-princess auto should have it online).

jmur1

mjeselskis · May 05, 2018, 08:43:58 PM

I did some tweaking on it today and got it working better. I didn't touch the relief, but I adjusted both detents a little at a time. Each detent is just a threaded adjustment with a lock nut. I probably turned the extend one in a 1/4 turn and backed out the retract one about a 1/2 turn by the time I finished tweaking. The retract detent still failed to kick out a few times but not nearly as much as before. I think I will get a gauge on the pressure line and check the relief pressure to make sure it's set right, but definitely made some improvements today.

blackfoot griz · May 08, 2018, 10:00:28 PM

Mike, I may be mistaken, but I think those come from the factory with the pressure relief set well below the maximum the 3,000 psi limit. That said, theoretically you could bump them both up and get more working pressure to your cylinder. The pressure gauge would answer this. I will be curious to see how this pans out!

ButchC · May 11, 2018, 05:57:00 AM

Have had one on my processor since I built it about 10 years ago and it has worked perfectly, hot oil/cold oil makes no difference. It does sit inside. One thing that happens to units that brave the weather is the detents get rusted and they need to be periodically disassembled and cleaned up.

PoginyHill · June 14, 2021, 11:30:24 AM

I was having issues with erratic operation of the auto-shut-off Prince valve on my recently purchased used Allwood splitter. I took the detent assembly apart and found the sensing port for the auto center function was plugged with junk. The detent would work OK on occasion, but most of the time did not release after the rod was completely retracted and the pressure rose above 2,000 psi. When it did work, the valve would release well below 1,000 psi.
The bottom of the spring shows the nature of the gunk in the sensing port and the small spool with o-rings. The small port can be seen just below the upper O-ring.

The detent assembly does not have any gaskets isolating from the outside world and has a small hole at the top of the adjusting screw to prevent pressure build-up. And detent assembly is separate from the hydraulic system (except for the tiny connection from the valve port that compresses the spring to release the ball bearing on the detent groove), so it is subject to contamination. This wasn't too much of a surprise as I needed to replace the hydraulic fluid when I got it because it was milky white with water contamination. Maybe someone got too aggressive with the pressure washer.

All back together and seemed to work fine, but haven't processed any wood yet since the cleaning.

mike_belben · June 14, 2021, 11:36:06 AM

ive heard of these valves but dont think ive ever used one. they auto cycle in both directions or just retract? if you send it forward, does it return automatically after full stroke or a certain pressure or... ? what do they do when working correctly?

PoginyHill · June 14, 2021, 12:01:49 PM

They make both. This one is for retract only. Need to hold lever to complete split, then engage detent for retract. Is supposed to return to center when piston is fully retracted. The small spool (pictured with O-rings) retracts the spring pressure holding the main spool in the retract position. The spring return to center then re-centers the valve.
A two spool valve with similar detents on both spools will auto cycle both ways. Engage once but operating both spools. Will auto retract when piston is fully extended and then auto shut off when cycle is complete.

Gearbox · October 14, 2021, 09:41:15 PM

I did find that all the problems went away when I went to a 70 gallon return line filter . I have a 4 inch cylinder with a 3 inch rod . A 16 gallon pump . On the return stroke 2.2 seconds the flow jumps to 36 gallons per min. Even with the 70 gallon filter I show 5 PSI run and 20 PSI return . Auto cycle from what I found out is they don't like back pressure.

moodnacreek · October 14, 2021, 10:10:44 PM

There are 2 of them here, one on a firewood splitter and the other on my board edger to run the sweep table. Here is the only way to use them: leave the lock nuts loose or off so you can turn the pressure detents adjustments by hand, whenever needed. The one on my edger is rigged to a foot treadle but the valve is right where I can reach the screws. They are very touchy and many give up on them but I can't work without it.