CHINESE INJECTORS FOR SHIBAURA N844 ???

Jerry/MT · Nov 26, 2017

Diesels need to be worked hard occasionally and the problem with many owners is they just don't to that very often. What you have in your exhaust is unburned fuel, partially burned fuel, carbon, etc. That stuff is getting on your exhaust valves, in the ring grooves, and in your crankcase, etc. Long term it's not good. Try to put the engine to work as often as you can. If you can't do that, change the oil more often and hope for the best.

fried1765 · Nov 27, 2017

Jerry/MT said:
Diesels need to be worked hard occasionally and the problem with many owners is they just don't to that very often. What you have in your exhaust is unburned fuel, partially burned fuel, carbon, etc. That stuff is getting on your exhaust valves, in the ring grooves, and in your crankcase, etc. Long term it's not good. Try to put the engine to work as often as you can. If you can't do that, change the oil more often and hope for the best.

Then I guess I will just have to place myself squarely in the category of "hope for the best".
Would Marvel Mystery oil in both the fuel and oil be a good idea?
I am far away from the tractor for 9 months each year, so it gets zero use those months.
It may get a total of 10 - 15 hours, for the year.
No such wet exhaust issues with my two gas Fords.

Jerry/MT · Nov 28, 2017

fried1765 said:
Then I guess I will just have to place myself squarely in the category of "hope for the best".
Would Marvel Mystery oil in both the fuel and oil be a good idea?
I am far away from the tractor for 9 months each year, so it gets zero use those months.
It may get a total of 10 - 15 hours, for the year.
No such wet exhaust issues with my two gas Fords.

Gas engines do not operate over the wide peak temperature range that a diesel engine operates. Telative to the diesel, the gas engine has a an almost constant peak gas temperature.

arto98607 · Nov 28, 2017

Wow

:laughing:

MiserableOldFart · Nov 29, 2017

Jerry/MT said:
Diesels need to be worked hard occasionally and the problem with many owners is they just don't to that very often. What you have in your exhaust is unburned fuel, partially burned fuel, carbon, etc. That stuff is getting on your exhaust valves, in the ring grooves, and in your crankcase, etc. Long term it's not good. Try to put the engine to work as often as you can. If you can't do that, change the oil more often and hope for the best.

That's interesting. I wonder what constitutes "working hard" sufficiently. Would mowing at the standard 540 PTO rpms do it or should it be brought closer to red line for some amount of time? I think mowing is the task that I run at the highest constant rpms for the longest time. Snow removal is generally done at somewhat more leisurely engine speeds, and loader work usually at around 2000-2200 engine rpm. It would seem natural to assume that these smaller engines tend to work harder most of the time anyway, no?

Jerry/MT · Nov 30, 2017

MiserableOldFart said:
That's interesting. I wonder what constitutes "working hard" sufficiently. Would mowing at the standard 540 PTO rpms do it or should it be brought closer to red line for some amount of time? I think mowing is the task that I run at the highest constant rpms for the longest time. Snow removal is generally done at somewhat more leisurely engine speeds, and loader work usually at around 2000-2200 engine rpm. It would seem natural to assume that these smaller engines tend to work harder most of the time anyway, no?

Working it hard generally means primary tillage, i.e. plowing, disking, etc The real issue here is the engine needs to be brought to operating temperature and then worked for an hour or two so that the cylinders get to higher wall temperatures (not necessarily max temperatures) and you have as near complete combustion as possible. Most of the non-ag users of tractors don't work their tractors very hard or very often and they have these kind of issues.
"It would seem natural to assume that these smaller engines tend to work harder most of the time anyway, no?" How can you say that without knowing what the load on the engine is? RPM alone is not an indicator of power output.

Let's put diesel engine on a dynamometer and set the engine speed with no load at 80% rated speed. The engine is developing zero net shaft power because there is no load other than internal friction. Now as we apply load via the dyno and let's hold the rpm constant. The airflow through the engine is the same but the fuel flow increases so the fuel/air ratio increases and the peak temperature in the cylinder increases to provide the necessary work to drive the load. As we add more load and hold rpm constant, again the airflow remains the same but the fuel flow increases and the temperature increases so the engine does the additional work to drive the load. This goes on until adding more fuel at constant airflow results in no additional power because there is not enough oxygen in the air charge to burn the additional fuel and so you have reached the max horsepower for that rpm and the exhaust gets smokey.. Actually, on modern engines, the smoke number will determine the max horsepower and no visible smoke will be the limiting power so it will be somewhat lower that absolute max horsepower.

So driving around with low load for short time periods means low temperatures in the cylinders and you won't burn off deposits and you will cause deposits and "wet stacking" or "diesel slobbers" to occur. Does that make it clearer?