Backhoe Need Max PSI Setting for LW-8 Backhoe Relief Valve

   / Need Max PSI Setting for LW-8 Backhoe Relief Valve #1  

3RRL

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Oct 20, 2005
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Foothills of the Giant Sequoia's, California
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55HP 4WD KAMA 554 and 4 x 4 Jinma 284
Hello gang,
It's been a long time ...
Today, I finally added a pressure gauge to my LW-8 Backhoe. You may remember that I got one from a friend, then fixed it all up and made a custom sub-frame for it to fit my 55HP Kama.

This is the name of the thread about it: "Diamond Shape Sub-Frame for LW-8 Backhoe" with lots of photos.

http://www.tractorbynet.com/forums/customization/188249-diamond-shape-sub-frame-lw.html

Anyway, here is my question ...
Does anybody know what the max PSI I should set the pressure relief valve on the LW-8?
It has self contained hydraulic system with a PTO mounted pump.

After installing the gauge, I found out I was getting only about 1,700psi !!
Right now I've adjusted the pressure relief valve to 2,250psi (same as the tractor hydraulics). However, I thought I remembered reading that the LW-8 and other Jinma backhoes have a higher relief setting than that? Maybe I'm wrong, but it doesn't hurt to ask all you experts out there.

If you want to see some photos of the gauge mod, I can take some tomorrow and post them.
Thank you,
Rob-
 
   / Need Max PSI Setting for LW-8 Backhoe Relief Valve #2  

greg_g

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JD3720 Cab, 300X loader with 4-in-1 bucket
I don't have a technical figure for you Rob, but suggest you check the pressure rating that's marked on the hoses/cylinders/controller. It would seem logical to set the relief valve to at least 10% below the potentially weakest link.

//greg//
 
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   / Need Max PSI Setting for LW-8 Backhoe Relief Valve #3  

RonMar

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May 25, 2005
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Port Angeles WA
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Jinma 284 delivered 06/28/05
Don't have specs for LW-8... FWIW, I believe my HW-03 is rated the same as my Jinma 284 tractor(looks like the same pump) at 16 MPa max, which converts to 2320 PSI... I think I set mine(loader and BH) around 2250 also...

Of course we want to see pics of your gauge mod... Your mods are always cool and very well done:)
 
   / Need Max PSI Setting for LW-8 Backhoe Relief Valve
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3RRL

3RRL

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Location
Foothills of the Giant Sequoia's, California
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55HP 4WD KAMA 554 and 4 x 4 Jinma 284
Hi Greg and Ron, thanks for the replies.
I guess I will stick with the 2250PSI I have it set to now. Just dug an 80' long trench and had plenty of power. Below are some photos showing the new gauge from front and back. I fastened it to the rear of the control housing with clamps and a shock absorbent hose liner. I cut the pressure line in to the valve and inserted a "T". All the fittings are re-usable hose fittings with JIC 1/2" for the pressure line, and 3/8" going to the gauge.

Thank you,
Rob-

1.jpg
2.jpg
3.jpg
4.jpg
 
   / Need Max PSI Setting for LW-8 Backhoe Relief Valve #5  

EE_Bota

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I set mine to 2350, so I think around 2300 is a good number.
 
   / Need Max PSI Setting for LW-8 Backhoe Relief Valve #6  

Bob Rooks

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Excellent work Rob.
My LW-6 was set at 2,250, as is my LiTW BH7600. And FWIW, My Mustang skid steer remote hydraulics are also 2,250.

Footnote: I'm running a Prince HC7-A PTO pump for the backhoe, and coincidentally, the dozer hydraulics are also set at 2,250 psig.
 
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   / Need Max PSI Setting for LW-8 Backhoe Relief Valve
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3RRL

3RRL

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Joined
Oct 20, 2005
Messages
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Location
Foothills of the Giant Sequoia's, California
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55HP 4WD KAMA 554 and 4 x 4 Jinma 284
Thanks guys,
Unfortunately, the riveted tag on the pump itself has been torn off so I was unable to identify the pump rating, which is why I posted the question. Anyway, the 2,250PSI setting seems to be comfortable for the hoe, so I will keep it there.
Thanks again,
Rob-
 
   / Need Max PSI Setting for LW-8 Backhoe Relief Valve #9  

psj12

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Oct 17, 2005
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Short OK
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KIOTI 551
Didn't you originally have an Italian BH on that Mount?
 
   / Need Max PSI Setting for LW-8 Backhoe Relief Valve
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3RRL

3RRL

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Joined
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Messages
6,825
Location
Foothills of the Giant Sequoia's, California
Tractor
55HP 4WD KAMA 554 and 4 x 4 Jinma 284
Didn't you originally have an Italian BH on that Mount?

Yes, but when I got this one, I moved the Nardi Backhoe over to Loretta's Jinma. Made a nice subframe similar to this one for that tractor.
 
 
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