longevity of bx2200 / BX22 engine

[Anonymous Poster]

I am interested in purchasing a bx2200 or BX22. Kubota uses the D905-E-BX engine. On the specifications it shows that to achieve 540 PTO RPM it is running at 3068 RPM. That seems to me pretty high. If I have to run this little engine at 3000+ RPM to get work done. How long will engine last? (with proper amintenance of course.

BTW: BX2200 / BX22 owners. How many hours of life do you expect from your engines?

Thank you so very much /forums/images/graemlins/smile.gif

 

[TresCrows]

The fact is that you rarely have to use full throttle or PTO rated speed for most work. Loader work, according to the manual is done at 1800-2200 RPM. I mow at about 2600 RPM, well below PTO speed on both my BX and about 2200 on my 2410. The D905 engine is very smooth running and consumes no oil and appears to stay cleaner than my 2410. With the boxblade I may use about 2600 give or take a bit for heavy work and when lifting a heavy load in the bucket I may momentarily goose it but it is simply not required to run the thing at PTO speed for most things. Brush hogging, rear finish mowers, tillers may be an exception. I expect my BX engine and tractor to last as long as my 2410, I see no reason to date that would make me think otherwise. Really, and some research will back me up, most engine wear occurs during (1) start, especially cold starts (2) lugging the engine or applying excessive load to it (3) running the engine hot and hard, overheating and possibly (4) infrequent useage (5) hot shut downs which may do bad things due to differential cooling--an admitted area of much speculation and little fact. A normal use of a BX should not expose the BX's engine to these conditions anymore than any other small tractor so I expect it to have a similar useful life. How many hours, well say it is 2,000 hours, a very reasonalbe number that would be 20 years at 100 hours a year. I expect something closer to 3,000 or more may be a real possibility. There were several threads on tractor life and I think I remember claims from 2,000 hours to 10,000 hours. I figure between 2,000 and 4,000 are more likely. We use my tractors quite a bit and about 100 hours a year is what we have been putting on each machine. J

 

[sandyc]

Hi Bugz:

The little Bota 22 hp engine is basically bullet proof. You want to think about rebuilding it at say 7000 hours. That is if it has had all of the right maintainence.
The diesel engine is meant to be used at a constant speed. For example, I was using the FEL to do some landscape work pulling down earth banks (landing area for old logging area) at the rear of my property and then pushing it out to grade. The tach almost never waived from 2000 rpms and the temp gauge never moved above cold for a few hours!
When I am running the snowblower I keep it almost wound tight in heavy snow or when I am removing what the town leaves at the end of my drive.
Basically, you run what you need to to get the job done.

 

[Egon]

My b7100 is approaching 2000 hours. It's run at full throttle minus a bit so it's probably around 2500 RPM. NO Tack. Doesn't use any oil. The dealer mentioned they had some out there with 10,000 hours on them.
I think the 7000 hours someone has mentioned is time to start building a rebuild fund.

Egon

 

[buzst]

Bugz,
If you check out the specs on the 905 on this site http://www.engine.kubota.ne.jp/english/index.html
you will see the torque curve peaks at 2600 RPM. and that max rated rpm is 3600. My opinion is that consistently running the engine this fast and on the down side of the torque curve will significantly decrease its life. The typicall solution would be to just run the engine more slowly, as most of us never run much over 2000 rpm, but because the pto is geared for the higher rpm you must run there to get PTO speed. This was a very poor design decision by kubota that probably will not effect the orginal owner of the machine but we will eventually see it reflected in the resale value of used bx's.

 

[gsxr1100]

As posted the bx power curve goes down at the max rpm. This is typical of all diesels. Nothing new here. I had a 1997 Ford F-350 7.3L Powerstroke diesel and it also had almost the the same power curve. Many diesels do not like high RPM's But they can take it. High RPM's are still low around 3,500. It would take years to kill a BX!

As far as the resale value stated, all I can say is I do not think so. If you run the mower and tiller at max RPM good luck. The max RPM will not have added value to a the lawn cut. The tiller will make the soil full of air and it will go down 6"+ when you steps on it or it rains. No need to run it that high. About 1/2 to 3/4 is just fine.

 

[Anonymous Poster]

<font color="blue"> BTW: BX2200 / BX22 owners. How many hours of life do you expect from your engines? </font>


With good maintenance, careful use, and a little bit of luck, I expect 20 or more years of use. I expect to put 200 -300 hours on this year. After my projects are done, most of the tractor time will be spent mowing (90+%), small chores, snow removal, etc. Probably around 100 hours a year. in 20 years that equates to 2300-2500 hours. I don't see that life expectancy to be unrealistic; it will probably go far beyond that.
I spoke to a lot of municipal owners (I do repair work on water/wastewater controls and meet alot of plant operators/ town managers in my travels) and there was not one that had a bad word to say about the longevity of any of their Kubotas.
In fact, several had 15 to 20 year old machines that were run hard/ put away wet for their whole life and needed no more than scheduled maintenance during that time (with the exception of mmm spindle bearings). The bx is for the most part a scaled down CUT, so life expectancy should be roughly the same.

BTW, regarding throttle settings: I haven't needed to crank it full out yet, even when box blading or tilling. It has a sweet spot (probably around that 2600 rpm mark that buzst mentioned) and it just purrs like a kitten and produces good power at that point. Why crank it up when you don't need to????
just my .02,
DaveL

 

[Anonymous Poster]

"but because the pto is geared for the higher rpm you must run there to get PTO speed."

buzst

that is one of my big concerns, if it's necessary to run the PTO at 540 rpm and the only way to get there is over 3000rpm, it seems over time this would not be conducive to long engine life. I did find out talking to my dealer, he said that with implements you do not "have to" run them at 540rpm, that # is just a number for highets efficiency, is this true?

Thank you all for your input.

 

[Chuck52]

The manual for my Brush Hog finishing mower lists "incorrect pto speed" as one cause for poor mowing results. I do know that if I am running it at much less than 540 rpm I get much more knock-down. I run an old L210, and get 540 pto rpm at about 2200-2400 engine rpm, so it's no problem for me.

Chuck

 

[sandyc]

Please note that the 540 rpm spec is for the rear pto. The mid pto is quite a bit higher.....the mower, snowblower and broom work from the mid pto.