Sorry for the delay. The pump was replaced due to the oil pressure being low after the engine warmed to operating temp 180-200degrees. It Would start out around 50psi the gradually drop to around 10psi. There is no abnormal sounds coming from the motor. When the oil pan was dropped there was very very minimal amount of metal shavings least non that caused any concern to me nor was there any type of trash or sludge buildup. The new replacement pump was a spot on match to the old one, so with that you could out the bolts bottoming out in the pan. Just for to rule out a bad gauge I went and got second mechanical gauge and swapped them out. Oil pressure at startup now is around 10 psi and running the tractor around 1600/1800rpms I'll see 25psi, but it will gradually drop to around 10 once the motor gets good and warmed up. I hope I answered most of the questions posted.
Oil & Fuel Oil Pressure After New Pump??? Jinma 284
- Thread starter duttymaxx
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buickanddeere
Super Member
Run straight 40wt, 50wt or 60wt oil to treat the symptoms . The solution will be a tear down and remachine journals then install "under size " bearings to restore clearances.
SPYDERLK
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Do not do this. These oils are too thick when "cold" to flow well and there will be damage/accelerated wear to oil starved parts during warmup. Use a multigrade; 15W40 or 20W50.
Bob Rooks
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Don't even think about that!
You might as well run straight STP "motor honey" and really screw up your engine. You can try taking down on the relief valve some more, but at this point I don't think the pump has enough volume to allow the valve to compensate. Like Spyderlk says, stick with a multi-grade oil so you get oil to the top end and camshaft in a timely manner. I see a bearing inspection in your future.
Bob Rooks
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For your amusement, here is a 16-710G EMD that we just finished rebuilding awhile back. These engines are pre-lubed with an electric oil pump for ten minutes prior to starting. This assures that any entrapped air is worked out, the oil filter is full, and that oil has reached all parts of the engine.
EMD 16-710G - YouTube
EMD 16-710G - YouTube
I've ran Rotella 15w40 ever since I got it 5 years ago. Bought it used with 362hrs on it. Hot pressure before was between 0.2mpa and 0.4mpa I never had a mechanical gauge on it up until a month ago when my pressure would drop a touch below 0.2 and my oil light would start flickering off & on.
quicksandfarmer
Veteran Member
I have a Jinma 354, which has the 485 engine, which is the same as the 385 engine you have except it has four cylinders to your three. Many of the parts interchange, including the oil pump. I remember the first day I got it --brand new from the dealer-- I used it for a while, and when it was good and warm I slowed the engine down to idle and the oil light came on. I would always get low oil pressure when engine was warm, with the pressure tracking RPM's. I just dealt with it by never letting the engine idle. A couple of years ago the oil pump failed and I replaced it, and all of the sudden I had much better oil pressure at all speeds and temperatures. At that time I read that the oil pump had been redesigned because of problems with it. So is it possible you got an old stock oil pump?
I'll add an anecdote that may or may not be helpful: one time I changed the oil, and I miscalculated how much oil I needed and came up a quart short. It's a fairly long drive for me to anywhere that sells diesel oil, and I had work to do, so I just put in a quart of whatever the convenience store had, probably 10w40 or similar. I figured there's so much in the sump that a little wouldn't hurt. I had dramatically lower oil pressure, and I ended up draining all of the oil and replacing it with Delvac. The moral is that the pump used in the Jinma is very sensitive to oil viscocity -- which is why pressure drops so much when the oil warms up.
I'll add an anecdote that may or may not be helpful: one time I changed the oil, and I miscalculated how much oil I needed and came up a quart short. It's a fairly long drive for me to anywhere that sells diesel oil, and I had work to do, so I just put in a quart of whatever the convenience store had, probably 10w40 or similar. I figured there's so much in the sump that a little wouldn't hurt. I had dramatically lower oil pressure, and I ended up draining all of the oil and replacing it with Delvac. The moral is that the pump used in the Jinma is very sensitive to oil viscocity -- which is why pressure drops so much when the oil warms up.
SPYDERLK
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No continuity there. It must be .02 and .04mpa (20 and 40 kilo Pascals) ~ 3 and 6PSI. Sounds like pressure has always been low. Also, based on quicksandfarmer experience it appears there is a higher volume pump available ... or else one having tighter rotor clearance hence much less internal leakage.