Oil & Fuel Oil Pressure After New Pump??? Jinma 284

   / Oil Pressure After New Pump??? Jinma 284 #21  
There is delta p across the relief valve, as there should be, because the engine cannot take all the oil the pump puts out. It's supposed to be that way.

if the bypass valve doesn't open the filter can act as a restriction.
Has oil pressure been measured at the pump discharge prior to the filter ?
A cam bearing can walk out of place and spill a lot of oil. Doesn't immediately make a bad sound .
 
   / Oil Pressure After New Pump??? Jinma 284 #22  
Is the oil pressure pretty good when the engine is cold? That is how my old chevy v8 acts- I know the bearings are worn but not knocking yet. If the pressure is poor even when cold, I would check to be sure that the oil pump pickup screen is not clogged- probably have to drop the pan to check this.
 
   / Oil Pressure After New Pump??? Jinma 284 #23  
When you put the new pump on did you forget to make sure it was tight or made sure the bolts did not bottom out with the new pump?
 
   / Oil Pressure After New Pump??? Jinma 284 #24  
If you didn't get a bad pump, then oil pressure is generated in the main bearings. Once the clearance gets to large you lose your pressure. Even so I've been able to get a good pressure boost on gas engines with a pump replacement. Has your pressure increased with the new pump?

No it virtually remained the same.
Then you didnt need to replace the pump. ... Your engine has some loose clearances on the crank, Id guess. Is the reason you replaced, because you noticed you were running lower oil pressure than when it was newer?
 
   / Oil Pressure After New Pump??? Jinma 284 #25  
Why was the original pump replaced? Was it broken?
 
   / Oil Pressure After New Pump??? Jinma 284 #26  
If you didn't get a bad pump, then oil pressure is generated in the main bearings. Once the clearance gets to large you lose your pressure. Even so I've been able to get a good pressure boost on gas engines with a pump replacement. Has your pressure increased with the new pump?

No it virtually remained the same.
Why was the original pump replaced? Was it broken?
... Not broken. - Im guessing low oil pressure. :confused3:
 
   / Oil Pressure After New Pump??? Jinma 284 #27  
... Not broken. - Im guessing low oil pressure. :confused3:
If the drop in oil pressure was immediate I would suspect a problem (which I was initially led to believe), but a drop in pressure over time (1,200 hrs.) suggests otherwise.
 
   / Oil Pressure After New Pump??? Jinma 284 #28  
If the drop in oil pressure was immediate I would suspect a problem (which I was initially led to believe), but a drop in pressure over time (1,200 hrs.) suggests otherwise.
Exactly. ... OP is not answering right now but I am very interested in how the tractor does with 10PSI pressure in high load work. I am involved in another thread [linked below] and told that poster he should see 15PSI or more -- but it was an educated guess. ... As you know the flow thru the bearing is most important because the bearings develop their own pressure in the loaded zone by running off center. -- They"ski" by dragging the viscous fluid thru the gap between the bearing elements. Pressures in this fluid wedge are huge. The fluid heats and continually escapes, requiring continuous "new" oil from the pump. -- I guess, if all bearings are near equally worn they are all getting their fair share of oil, even at 10PSI.

http://www.tractorbynet.com/forums/john-deere-owning-operating/368853-diesel-engine-oil-operating-pressure.html?highlight=#post4541517
 
   / Oil Pressure After New Pump??? Jinma 284 #29  
Exactly. ... OP is not answering right now but I am very interested in how the tractor does with 10PSI pressure in high load work. I am involved in another thread [linked below] and told that poster he should see 15PSI or more -- but it was an educated guess. ... As you know the flow thru the bearing is most important because the bearings develop their own pressure in the loaded zone by running off center. -- They"ski" by dragging the viscous fluid thru the gap between the bearing elements. Pressures in this fluid wedge are huge. The fluid heats and continually escapes, requiring continuous "new" oil from the pump. -- I guess, if all bearings are near equally worn they are all getting their fair share of oil, even at 10PSI.

http://www.tractorbynet.com/forums/john-deere-owning-operating/368853-diesel-engine-oil-operating-pressure.html?highlight=#post4541517
Correct. 10 psig is still getting almost the same volume of oil as 30 psig in the oil gallery, but there is no margin for error. Still waiting for the disposition of his gauge.
 
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   / Oil Pressure After New Pump??? Jinma 284 #30  
Correct. 10 psig is still getting almost the same volume of oil as 30 psig in the oil gallery, but there is no margin for error. Still waiting for the disposition of his gauge.
Actually a little more oil at any given rpm at the lower pressure because of less internal "leakage" in the pump itself. ... Thats good, but the problem I see is if there is a single point taking so much flow that is responsible for the marginal pressure. That would be starving other similar parts.
 
 
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