white smoke: can it be because there's too much oil...

[jonyyuma]

Pressure in the crankcase is not a good thing anyway?It comes from several failures or wear points? Are you getting this tractor pretty cheaply. If not why bother?? You can hunt for one with less what-ifs?? or an engine rebuild?

 

[rsewill]

I would speculate that it is 95% likely you have a bad injector. If you wipe the fuel off the dipstick with your fingers, then rub your fingers together, you will notice that your fingers will be 'clean' where you rub. That's because the fuel acts as a solvent to 'clean' the oil from between your fingers. A bad injector injects excess fuel which smokes white and also runs down past the rings. You can remove all the injectors and have them tested. My experience with big trucks is that once one injector goes because it is worn, then the rest will soon follow, usually within a year. Most likely you don't run your tractor anywhere near as much as a truck so changing them all is a judgement call.

 

[Jerry/MT]

I agree with you and the others that diesel in the oil is likely. Current owner of the tractor said that the oil hasn't seemed low and he hasn't had to add oil. So the only way the oil would be significantly higher than "full" is added diesel.

I need to check smell and compare oil in the tractor to "good" oil to see if it feels different. But, I didn't notice any smell before.

I need some clarification on what "blow-by" is: my understanding is that it's exhaust gas during/after combustion goes past the rings into the crankcase. So the gases coming out of the breather should smell like exhaust. One would also think it would be white, like what's coming out of the exhaust pipe. I took the breather cap off and put my hand over the opening and it seems to build pressure the longer I hold it there, but when I take my hand off, there's no smoke or exhaust smell at all, just some "clean" oil spritzed on my hand.

Is that right?

If so, then it appears that it's unburned fuel and blow-by, because building pressure would seem to indicate that something is adding to the volume of the crankcase--unburned fuel, etc.--just doesn't seem to be exhaust. And it has white smoke and is rough running, meaning bad compression or bad injectors.

Worst case scenario is then a new injector pump, new rings (engine rebuild), reground valves/valve seats or a new head, and new seals all around. That about right? Just $2500...:thumbsup:

The oil could be higher on the dip stick if coolant leaked into the crankcase, too.
Blowby can be anything from normal leakage past the rings to raw cylinder gases due to a hole burned in the piston crown, cracked piston, broken rings, worn rings, etc. Excessive blowby occurs in these latter examples. This won't smell like normal exhaust gas because the pressure and the temperature in the cylinder are too low for self ignition to take place let alone burn to completion.

I think you'll be looking at more than just some work on the head, Maybe a new piston or two, new or rebuilt injectors. At the very least, run a compression test so you know how many cylinders you're looking at fixing. I don't know why you'd need a new injector pump. Hopefully the bottom end isn't damaged from running with contaminated oil.
Make sure you can source the parts for this machine. Japanese tractors are notorious for poor parts availability especially the brands that are not popular in the US. If you can find parts, they are generally expensive.

You didn't ask me but Im going to tell you anyway. I would not buy this tractor with the problems you've all ready witnessed with it unless you get it for free and want to restore it. Why do you think the present owner is selling it?

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