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

   / Oil Pressure After New Pump??? Jinma 284 #1  

duttymaxx

Member
Joined
Aug 15, 2016
Messages
28
Location
Cabot Arkansas
Tractor
Jinma 284
Does anyone know what normal operating pressures on the oil pump is supposed to be? I recently had to replace my oil pump on my Jinma 284 with the Y385 engine, man what a booger it was too. Anyway after the replacement I'm only seeing around 7-10 psi while I'm bush hogging, tractor is running around 180-200 degrees and I'm guessing it's running around 1600-1800rpms ( tach and hour meter quit working several years ago with around 540hrs on it ) I've used the oil gauge on the instrument panel and also recently put on a manual oil pressure gauge ( the manual one was installed prior to old pump replacement )

What else could cause low oil pressure? The new pump came with a new pickup tube and gaskets.

Is 7-10 psi normal/ok to run the tractor at?

Tractor has around 1000-1200hrs on it now guesstimating.

Any insight would be greatly appreciated.
 
   / Oil Pressure After New Pump??? Jinma 284 #2  
Are you using 15w-40 lube oil?
 
   / Oil Pressure After New Pump??? Jinma 284 #4  
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?
 
   / Oil Pressure After New Pump??? Jinma 284 #5  
7 to 10 psig would be okay for idle at operating temp., not so for 1,800 r/m under load.
Normally that would indicate worn bearings. What is the oil pressure at idle at operating temp.?
Are your radiator fins spotlessly clean? Have you tried adjusting the oil pressure at the bypass
valve in the filter head?
 
   / Oil Pressure After New Pump??? Jinma 284
  • Thread Starter
#6  
7 to 10 psig would be okay for idle at operating temp., not so for 1,800 r/m under load.
Normally that would indicate worn bearings. What is the oil pressure at idle at operating temp.?
Are your radiator fins spotlessly clean? Have you tried adjusting the oil pressure at the bypass
valve in the filter head?

Radiator is clean, spent 2 hours cleaning it before bush hogging. Oil pressure is close to zero at idle. I haven't adjusted the bypass didn't actually know you could, to adjust the pressure is it clock wise or counter clockwise to increase?

How big of a job is it to replace the bearings? And more specifically what bearings are you referring to?

Also if anyone is needing a oil pump for a Y385 I just happen to have a good used one I'll sell cheap. .
 
   / Oil Pressure After New Pump??? Jinma 284
  • Thread Starter
#7  
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.
 
   / Oil Pressure After New Pump??? Jinma 284 #8  
Radiator is clean, spent 2 hours cleaning it before bush hogging. Oil pressure is close to zero at idle. I haven't adjusted the bypass didn't actually know you could, to adjust the pressure is it clock wise or counter clockwise to increase?

How big of a job is it to replace the bearings? And more specifically what bearings are you referring to?

Also if anyone is needing a oil pump for a Y385 I just happen to have a good used one I'll sell cheap. .
The bypass valve adjustment is under the acorn nut on the filter head. Clockwise to increase the pressure. try one quarter turn at a time. It's also possible you could have a weak or broken spring in the valve. Replacing the crankshaft and rod bearings wouldn't be too bad, just more involved than replacing the oil pump. Not sure if you could replace the front and rear main bearings without removing the engine though. Not that familiar with your tractor.
 
   / Oil Pressure After New Pump??? Jinma 284
  • Thread Starter
#9  
The bypass valve adjustment is under the acorn nut on the filter head. Clockwise to increase the pressure. try one quarter turn at a time. It's also possible you could have a weak or broken spring in the valve. Replacing the crankshaft and rod bearings wouldn't be too bad, just more involved than replacing the oil pump. Not sure if you could replace the front and rear main bearings without removing the engine though. Not that familiar with your tractor.

Thank you I'll try that and see where that gets me...
 
   / Oil Pressure After New Pump??? Jinma 284
  • Thread Starter
#10  
The bypass valve adjustment is under the acorn nut on the filter head. Clockwise to increase the pressure. try one quarter turn at a time. It's also possible you could have a weak or broken spring in the valve. Replacing the crankshaft and rod bearings wouldn't be too bad, just more involved than replacing the oil pump. Not sure if you could replace the front and rear main bearings without removing the engine though. Not that familiar with your tractor.

Cranked up the oil bypass valve no major increase in pressure at idle or 1600-1800rpms. Gave it a full turn and a half.
 
 
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