Smokey Kubota

[Anonymous Poster]

Just thought the following story may be of intrest.
We recently received a used Kubota L1-18DT from Japan. 1008 hours. Very clean ,tidy, goodlooking unit. Unfortunatly, the engine had a nasty ,fairly heavy,blue smoke haze when free running around the yard.

We decided to try to work the unit hard for a while, too see if the smoke would improve.Failing that, we would have to strip the engine and deglaze the bores and repair with new pistons ,rings etc. So we fitted a slasher and put it to work in heavy wet grass(we had a lot of rain recently in sunny Sydney ,Australia).Loading it to the limit by adjusting the slasher up/down just on the borderline of stalling the poor engine. Once or twice the going was just too heavy for the little Kubota,stalling, but restarting every time. I'm sure most owners would not give their tractors a caneing like that.

The engine responded beautifully. After about an hour the smoke had completly cleared, the engine was crisp and strong,the tractor was doing everything right.

It seems the previous owner had used it only with light loads and the workout we gave it, has really improved the little tractor.At least it saved a deglaze and several days work.
It reinforces the importance of running diesel engines with some decent load on them. The improvent we noted was quite staggering.It went from a unit that was obviously in need of engine repairs, to a tractor which works as good as it looks.

 

[Thomas]

Kinda like the old saying..use it or lose it. /w3tcompact/icons/wink.gif

 

[Youare]

I went to a seminar on hydraulic components years ago and one thing that was said stuck with me. He said every mechanical thing has within it a little computer that records all it's use. In that computer there is a failure setpoint and when that point is reached the part will fail.

His point was that everytime you abuse a piece of equipment that gets recorded in the computer and eventually the failure point is reached. If you abuse something one day, taking it easy on it the next day does not reverse the abuse of the previous day.

I tend to lean toward not pushing my tractor in an effort to make it last longer before I have to repair something. When it comes to engine RPM I have a habit of running the engine in the 1500 to 2000 RPM range. I don't use a brush hog or any other PTO driven device that requires 540 RPM.

My question would be, how would one determine what is a healthy engine load, and what is too much and too little?

Right now I observe the exhaust, when I see a slight blue haze I maybe working it a bit. I don't know if diesel truck exhaust is a good gauge, black smoke is hard work, and light blue for a short period is okay.

Randy

 

[rbargeron]

Randy - I believe you and BillK are both right, and that's because you're taliking about opposite ends of the same issue.

The "little computer" does indeed record everything - including periods of under-use. New engines have microscopic roughness on all the parts that needs to get smoothed out. This "breaking in" won't happen if the engine is never worked - in fact, soot and sludge will fill just pack into the surface irregularities instead. If this goes on long enough, the rings will no longer move in their grooves, too much oil will go past them and get burned.

The un-broken-in engine sometimes has one more chance to "catch up" . The engine has to be vigorously worked for a few hours. During this workout, the sludge gets royally heated and burned off, and the rings finally seat, getting fitted to the cylinder wall better. It doesn't always work, but on a severe smoker there's nothing to lose so it's worth a try.

All diesels smoke a little - black if low rpm and/or too much fuel, blue if below operating temperature. And they all benefit from an occasional workout. Working an engine at its rated horsepower makes its little computer happy. /w3tcompact/icons/smile.gif

 

[Richard]

Working an engine at its rated horsepower makes its little computer happy

Is that sort of like hitting "control/alt/delete"??

Richard

 

[MDNick]

Remember the Commodore 64? "RUNSTOP/RESTORE"?

 

[rbargeron]

No, it's more like signing your computer up with United Devices to work all night doing molecular binding site calculations for anthrax research. This isn't a joke - check out <A target="_blank" HREF=http://www.chem.ox.ac.uk/anthrax/>this link</A> - I think this is the coolest thing I've seen in a very long time - by using computers all over the world, Oxford researchers are getting 17,000 years of computing done in a month or so.

Guaranteed to seat your ram chips and stop the smoking when your computer is idling. /w3tcompact/icons/cool.gif

 

[GlueGuy]

I'm with you on this one Dick. There is a happy medium for engines. Over due it too much, and you put unecessary wear on certain parts, but the reverse is true as well. Need to seat those rings, and light-duty stuff constantly will never get them there.

I had a friend in high school that got a Nova SS, with the 396 V8. It was the biggest dog any of us had ever seen. Almost couldn't get out of its own way. He said the thing was such a dog, that the engine should be replaced under warranty, but the dealer said no way. So, he decided that since it was under warranty, he would "push the envelope." He proceeded to operate the engine at the highest RPM he could muster, and just thoroughly wanged it. His hope was the engine would blow up, then he'd get his warranty replacement.

Just the opposite happened. The engine had apparently been "too tight", and his wanging loosened things up. The engine then became a great performer.

I personally think he was lucky. But it does illustrate the point that new engines have to get past the new stage, and they shouldn't be pampered, but they also shouldn't be abused.

 

[njrqs]

Bill

My Import is similar. I hear they don't get a lot of use in Japan, and only plod around the rice paddies.

A bit of hard work is what my mechanic said is good for them. We have had no rain for a year (to speak of), so have not been slashing and the exhaust has a bit of oil in it. He reckons with a good hard slashing session, that will all clear up.

I don't see how you can hurt the diesel providing you don't over-rev it. Load never hurts a diesel from what I gather !

Cheers