oil psi ? ranch king tractor.

   / oil psi ? ranch king tractor. #1  

gochenour799

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Sep 1, 2010
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I bought a ranch king 25 HP 4x4 diesel tractor with a 72" finish mower to mow my yard with it had 70 hrs on it . It has a different style oil psi gauge on it than I am used to and I thought it was lying to me . So I put a autometer mechanical gauge on it. Here's my problem at start up it has 80 psi cold . The longer you mow the less oil psi I have 2 hrs in @ 2200 rpms I have 20 psi when I idle it down to shut it off I have 0 psi . I read about the bypass valve and adj. It . This only brought the cold psi up not the hot . I run rotella 15w40 and wix filters and change them often . I am thinking oil cooler maybe the next step ? Has anyone else had this happen ? I use the rule 10 psi for every 100 rpms is that too much for this application? it just worry me to idle it down to shut it off .
 
   / oil psi ? ranch king tractor. #2  
Oil pressure is discussed quite frequently, so the answer to this is probably reasonably simple. But I need something cleared up first. You're giving pressure in psi (SAE), yet every Chinese oil pressure gauge I've seen is graduated in MPa (metric). Are you converting metric to SAE for purposes of posting? Or does your tractor actually have an OE gauge that reads in psi?

//greg//
 
   / oil psi ? ranch king tractor.
  • Thread Starter
#3  
No like I said in my first post I.don't trust that gauge so I installed a mechanical autometer gauge that reads psi
 
   / oil psi ? ranch king tractor. #4  
80 psig is way too much for a cold startup with a multi grade oil. I would calibrate your test gauge for accuracy.
The other symptom you describe as losing oil pressure as the engine warms up suggests worn out camshaft bearings or crankshaft main bearings.
 
   / oil psi ? ranch king tractor. #5  
Lets break out the calculator and do some math. You say, 10 psi for each 100 rpm.
At 2,200 rpm x 10psi/100 rpm = 220 psi. I dont think so!

How about 1psi/100 rpm.
2,200 rpm x 1 psi/100rpm = 22psi.

Now some questions, what does the OEM pressure gauge indicate?
What is the coolant temperature?

22psi= 0.151 Meg Pascal.

As for the pressure relief valve, it limits the maximum pressure and has no effect on the operating pressure.
At 80 psi you risk blowing the crank shaft oil seals. What is the rpm that gives 80 psi?

Is this tractor new under warrantee? Maybe talk to the dealer?
 
   / oil psi ? ranch king tractor. #6  
Sorry, when you said "It has a different style oil psi gauge on it than I am used to", I thought that meant you didn't understand the metric gradients on the OE gauge. So yeah, a cold 80 to a hot 0 is considerably out of the norm - if it's truly accurate. It might not hurt to get an opinion from a 2nd mechanical gauge. Some folks couldn't cope with the metric pressure indications and went to mechanical gauges like you. Others learned to understand the OE metric indications by converting to psi on the fly. Out to the closest half pound:
0.1 MPa = 14.5 psi
0.2 MPa = 29.0 psi
0.3 MPa = 43.5 psi
0.4 MPa = 58.0 psi
0.5 MPa = 72.5 psi
So if what your mechanical gauge is telling you the truth, the OE gauge had to have been pegged during a cold startup. Is this correct?

Most owners report cold startup pressures with 15W40 are typically between 0.3 and 0.4 MPa, hot idle pressure is safe down to down to about 0.05. Operating pressure at temperature at speed should hover between 0.2 and 0.3

Which oil filter are you using?

//greg//
 
   / oil psi ? ranch king tractor.
  • Thread Starter
#7  
U
Lets break out the calculator and do some math. You say, 10 psi for each 100 rpm.
At 2,200 rpm x 10psi/100 rpm = 220 psi. I dont think so!

How about 1psi/100 rpm
2,200 rpm x 1 psi/100rpm = 22psi.

Now some questions, what does the OEM pressure gauge indicate?
What is the coolant temperature?

22psi= 0.151 Meg Pascal.

As for the pressure relief valve, it limits the maximum pressure and has no effect on the operating pressure.
At 80 psi you risk blowing the crank shaft oil seals. What is the rpm that gives 80 psi?

Is this tractor new under warrantee? Maybe talk to the dealer?

Your right 10 psi was a mistake . I ment 1 sorry . Rpm @80 psi is idle @ start with cold oil , as soon as it starts to warm up the oil psi drops .
the own gauge says the same thing pegged @ start up 0 @ shut down .
No warranty , no help its a rual king tractor .
Water temp is fine and I never have had it hot .
 
   / oil psi ? ranch king tractor.
  • Thread Starter
#8  
Sorry, when you said "It has a different style oil psi gauge on it than I am used to", I thought that meant you didn't understand the metric gradients on the OE gauge. So yeah, a cold 80 to a hot 0 is considerably out of the norm - if it's truly accurate. It might not hurt to get an opinion from a 2nd mechanical gauge. Some folks couldn't cope with the metric pressure indications and went to mechanical gauges like you. Others learned to understand the OE metric indications by converting to psi on the fly. Out to the closest half pound:
0.1 MPa = 14.5 psi
0.2 MPa = 29.0 psi
0.3 MPa = 43.5 psi
0.4 MPa = 58.0 psi
0.5 MPa = 72.5 psi
So if what your mechanical gauge is telling you the truth, the OE gauge had to have been pegged during a cold startup. Is this correct?

Most owners report cold startup pressures with 15W40 are typically between 0.3 and 0.4 MPa, hot idle pressure is safe down to down to about 0.05. Operating pressure at temperature at speed should hover between 0.2 and 0.3

Which oil filter are you using?

//greg//

I understand it I just didn't trust it , but it shows the same thing as the new one.
 
   / oil psi ? ranch king tractor. #9  
Again please, which oil filter are you using? And not that Rural King ever did much better, but they sold their rebadged Jinmas as Tractor Kings, I don't know who sold Ranch Kings

//greg//
 
   / oil psi ? ranch king tractor. #10  
Hate to say it but you may have a spun & locked crankshaft or camshaft bearing. If the issue isn't resolved with the oil filter, then I'd plan on dropping the oil pan. :( I recommend performing an oil analysis.
 
 
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