Have we been doing it wrong? High rpm's bad when not needed?

[confederatemule]

I a simply telling how I do it. Right or wrong ??. My diesel engines have never give any trouble of any kind.

I have worked on and operated equipment, of one kind or another, with Diesel Engines since mid 1960s.

I bring them above idle only when I need more power. I do not run at any RPM higher than I need to get the job done. I also am careful not to lug the engine.

Course, I am the sort of person who does not care how anyone else does something. I do things the way that works best for me.

Mule

 

[LouNY]

A diesel engine will not generate very much heat in the exhaust unless it has a load on it. High rpm's with no load it has a tremendous amount of air being pushed through with very little fuel. Very little fuel= very little heat.
The more load the more heat it will also generate as it takes fuel to carry the load, more fuel = more heat. Moderate load will provide heat and minimal particulates, heavy loads will provide lots of heat also lots of particulates.
If you really want to watch that install a pyrometer in the exhaust and watch the temperatures as the loads vary.

As far as fuel dilution in cold weather idling it is quite common, especially with low rpm idling. As the engine will have a difficult time even getting to operating temps without a load. That is the main reason that we cover our radiator openings in cold weather. The warmup times are greatly reduced and the performance is greatly increased.

A dpf equipped engine will regen much better when at temp then when it is cold. Diesel pickups will demonstrate that quite easily if you have a monitor to watch the regens, cold weather the exhaust will lose so much heat that the system will dump extreme amounts of fuel into the exhaust to bring the temps up.

 

[RandyT]

Thank the Lord I don't have to worry about that regen <censored.>
However, my BX2660 manual says to keep my rpm's around 3100 or so when mowing the grass (regardless of engine load I assume as the manual doesn't say anything about that.) So, am I doing it wrong and possibly harming my little 3 banger (25 1/2 hp)?

I would say you are fine. I suspect the 3100 comes from maintaining speed for the pto not so much for the power. And I would also say that 1800-2000 would be sufficient to maintain proper oil flow to the hydro. Most of the stuff I work on recommends 1800-3600 input rpm to the pump.

 

[RB5]

Interesting. I run most of the time at 1500 RPMs unless I need more for pto or loader work. I have a Deere 4044M. The only time it has ever gone into regen was when I idled a little more than usual while getting off to move something or do work or when my father in law ran it and had no clue about the regen and newer emissions controls. I'm sure he ran it at low RPMs like the older tractors. When I got it back he told me it was sounding loud and he shut it off during regen. That regen took a while when I started it back up. I use lower gears if I need to move slower. I've had the tractor at least 6 or 7 years with no issues.

 

[RB5]

Let me check what the manual for my 1964 Ford 4000 says about this and I’ll get right back to ya’.

I hope yours is in better shape than my 1970 Ford 2000 gas tractor. At the end I spent more time repairing than using it every time I wanted to do something. The last time I tried to use it the tractor got stuck in gear. Parked it and it has not been moved since.

 

[Elviscaretaker]

It's interesting reading the issues others have and how they do things. I run my TC-30 at about 1800-2000 rpms for most things, no issues but mainly to keep it from bogging down. It's a tier 0 so no emissions crap on it. Now my Duetz (tier 4) I tend to run at an idle for loader work, moving hay etc. In the field in E mode for the pto about 1400-1600 rpm's(?). I'm pretty sure I can get away with 800 rpm's if it were not for the needed pto speed. Only time I crank it up is when I'm on the road and want to get there faster. At 500 plus hours I don't THINK I've had a regen on it. But it isn't noticeable on this one if it does nor does it tell you. Dealer just says run it full throttle to clean out the filter for about 30 minutes (did it once, got bored). Other than that I basically run it as needed with keeping the revs lower and it's only noisy when I have equipment attached to it. Then my hearing is shot so maybe it is noisy One of my riders has 35k hours on it with a 25hp kohler in it, never rebuilt and I beat the crap out of this one as my edge mower and trail mower. Full throttle all the time .... Just kept up on filter/oil changes is all. All in fun...

 

[jyoutz]

All I can say is, I'm sure glad I don't have to deal with any of that.

I will say the only time I see smoke (soot emanate from either of my M9 turbo charged pre 4 diesels) is a little puff on cold start and if I'm working them hard like a full bale chamber or mowing tall hay at a fairly high ground speed. Other than that I se no visible 'particulates', aka: soot and I'd assume your post 4 units exhibit the same characteristics except the particulates get captured in the DPF or in the case of higher power diesels, burned by the oxidation catalyst, aka: DEF.

I will never own a post 4 diesel, ever.

I can’t say that there’s anything to deal with. My regeneration events have all occurred when I was working, rotary cutting or grading the road. I just raise the throttle a bit and keep working. I see a bit of white smoke for 10-15 minutes and then it’s over.

 

[TractorNoob85]

I'm not so much concerned about the regen events as I am about the ash buildup that WILL occur over time. Hopefully, that crap is easy to clean out with water when the time comes.

 

[jyoutz]

I'm not so much concerned about the regen events as I am about the ash buildup that WILL occur over time. Hopefully, that crap is easy to clean out with water when the time comes.

The required minimum longevity for a tractor DPF is 3,000 hours, with many lasting twice as long. Unless you use your tractor for full time farming or other work, most compact and utility tractor owners will never experience a DPF failing.

 

[CloverKnollFarms]

Are there many DPF units past 3000 hours yet? I mean, utility tractors? Most folks use them 50 hours per year? And DPF has been on them for what, 10 years? Probably not many units past 3000 hours? Just browsing used tractor listings the past few years, most post DPF units are still under 1000- 2000 hours.

Which supports the idea that we don't use them enough to really expect an issue, except for ECM issues that some have.

 

[5030]

I'm not so much concerned about the regen events as I am about the ash buildup that WILL occur over time. Hopefully, that crap is easy to clean out with water when the time comes.

It's not actually. Once the DPF cannister accumulates sufficient burned ash to trigger the sensor and cause a dash light to illuminate (and they all will at some point), the tractor must go to a dealer and the element in the cannister MUST be removed and cleaned (or replaced) in accordance with EPA approved procedure as the ash is considered a hazardous substance and must be disposed of correctly in an approved landfill. Therein lies the rub. If there is any damage to the substrate, the element must be replaced and you as the end user CANNOT replace it and/or reset the ECM to extinguish the light. Been my experience with big trucks, that at least 75% of the substrate elements have damage that precludes cleaning them so they must be replaced. Good part is, the element should not need renewed or cleaned for many rears under normal use. What normal use (definition) is is a crapshoot. I do know that Kubota says it's 1300 regens, other manufacturers, I have no idea.

Bottom line is, it's not a user serviceable item and the end user cannot reset the ECM either. If you keep the tractor long enough, you will have to have an authorized dealer perform the service.

 

[Lefty7]

I'm in the use-only-whay-ya-need camp, and sometimes what ya need does take some rpms. Top of the list for me is the Phoenix/Sicma reverse rotation tiller on first tilling of the season. I love the way it tills, as it turns all but the biggest rocks back under, but dragging those tines forward while they're churning backwards takes some. After I learned the machine better, I realized I could cut the rpm down to about two-thirds the mfr.'s suggestion (6C) and still get the same results - just go slower; usually the 400-500 rpm range is sufficient. The one time I was WFO was to chain-drag a huge rock from my neighbor's property to mine. It was way too big to lift, but I wanted it for a dam I was building. It also required low/low and 4WD.

 

[hiddentacocatneddih]

Dpf is normally not the failure

It's the EGR rotting thru filling the engine with coolant grading the block that is

 

[Beaver Cove Deere]

Fuel dilution in lube oil when analyzed by a competent lab like Blackstone for instance is a sure sign of either worn rings or injector issues, neither of which I have with either of my pre-4 Kubota M9's and why I'd be very hesitant when buying a used machine, especially one with excessive hours on it and / or no supplied with maintenance records. My OS M9, I bought used from a JD dealer of all things, but it came with not only the original owners manual and the shop manual (which I didn't need because I already have one), but it came with dated service records, right down to the brand of lube oil and gearbox oil installed as well, plus all the filters had the change hours painted on them in paint pen, which is something I do as well as it gives me a quick visual reference as to pending service time. In reality I would not be at all hesitant to purchase a post 4 tractor if I required one, which I don't as both my pre 4 tractors run flawlessly but I would wait until the manufacturers work all the bugs out of them and in my case, for the power I require, they would not only be SCR units but DEF injection as well. I believe under EPA mandate, any unit in the excess of 90 stub pto output requires DEF injection as well as Selective Catalytic Reduction (SCR) or what is now present on units above 26 stub (pto) horsepower. Keep in mind that tractors are rated (for emissions compliance with stub (pto) horsepower, not flywheel horsepower. Motor vehicles such as cars or trucks are rated at flywheel output, which is always greater than driveshaft power, usually 10% more. 10% is the rule of thumb used to take into account parasitic loss in the transmission and hydrostats are usually more than 10% as a rule because of the fluid coupling (hydrostatic drive). In my applications, where I require maximum output at times, a hydrostatic transmission won't work, I must have a conventional gearbox. The one thing I don't want is a dry clutch because many times I'm operating in a 'half clutch' situation, consequently I run tractors with wet, multiplate clutches that are basically immune to clutch plate wear from half clutch operation. My goal is to always have tractors with NO dry clutch in the bellhousing and that is exactly what my hydraulic shuttle Kubota's give me.

I can literally 'ride' the clutch pedal all day and not wear the clutch one bit. Not that I do but I could if necessary. Even with a hydrostat, you will have a dry clutch in the bellhousing that will eventually need replacement and that replacement entails splitting the unit. I don't have that issue with the hydraulic shuttle as all that is in the bellhousing is a damper plate connected to the crankshaft output flange and another plate connected to the transmission input shaft via a set of radial coil springs with the sole purpose of dampening the shock load imposed by abrupt directional changes and even those are mitigated by the proportional hydraulic valving that controls the 'lockup' pressure on the wet clutch pack that drives the gearbox and transmits power to the wheels and eventually, the ground. In reality, it's a very well engineered system that operates flawlessly and eliminates the dry clutch entirely and the hydraulic actuator valve on the side of the main gearbox also maintains optimum lockup pressure and it adjustable if required. it does require a special fitting and liquid filled pressure gage to check but I have that and when I check it, it's always within Kubota listed specification for correct lockup pressure, even on my 6000 plus hour machine.

I believe JD also offers a similar setup but they call theirs a 'power shuttle' transmission.

No other problems that I can see. Machine does not smoke unless pushed hard to a bogging condition. No oil consumption. That was at 982 hours.

 

[JCoastie]

It's not actually. Once the DPF cannister accumulates sufficient burned ash to trigger the sensor and cause a dash light to illuminate (and they all will at some point), the tractor must go to a dealer and the element in the cannister MUST be removed and cleaned (or replaced) in accordance with EPA approved procedure as the ash is considered a hazardous substance and must be disposed of correctly in an approved landfill. Therein lies the rub. If there is any damage to the substrate, the element must be replaced and you as the end user CANNOT replace it and/or reset the ECM to extinguish the light. Been my experience with big trucks, that at least 75% of the substrate elements have damage that precludes cleaning them so they must be replaced. Good part is, the element should not need renewed or cleaned for many rears under normal use. What normal use (definition) is is a crapshoot. I do know that Kubota says it's 1300 regens, other manufacturers, I have no idea.

Bottom line is, it's not a user serviceable item and the end user cannot reset the ECM either. If you keep the tractor long enough, you will have to have an authorized dealer perform the service.

Dunno about all that, Dealer pulled mine, soaked it overnight, flushed it with water and reinstalled. No fanfare. Did have to replace the gasket which they didn't expect or have on hand, so that was a couple day delay getting it back. They actually said cleaning them is no big deal.

 

[TractorNoob85]

It's not actually. Once the DPF cannister accumulates sufficient burned ash to trigger the sensor and cause a dash light to illuminate (and they all will at some point), the tractor must go to a dealer and the element in the cannister MUST be removed and cleaned (or replaced) in accordance with EPA approved procedure as the ash is considered a hazardous substance and must be disposed of correctly in an approved landfill. Therein lies the rub. If there is any damage to the substrate, the element must be replaced and you as the end user CANNOT replace it and/or reset the ECM to extinguish the light. Been my experience with big trucks, that at least 75% of the substrate elements have damage that precludes cleaning them so they must be replaced. Good part is, the element should not need renewed or cleaned for many rears under normal use. What normal use (definition) is is a crapshoot. I do know that Kubota says it's 1300 regens, other manufacturers, I have no idea.

Bottom line is, it's not a user serviceable item and the end user cannot reset the ECM either. If you keep the tractor long enough, you will have to have an authorized dealer perform the service.

How many have you needed to replace so far?

 

[tacticalturnip]

I'm a big fan of my ridiculously simple tractor, even if it is obese and under powered. Like me.

 

[MRTOES]

I run older tractors mostly. I still do not use higher RPMs because among other things its the best way for a diesel engine to rip out a clutch under a load.....

 

[dadohead]

The weakest link on your tractor by far is the transaxle (especially if its HST). Engines almost always exceed the life of the tranny.

High rpms do NOT hurt an engine at all but lowers the torque put on the engine and transaxle components. High torque is what wears and breaks tractors. So error toward higher rpms for longer tractor life.

 

[jyoutz]

It's not actually. Once the DPF cannister accumulates sufficient burned ash to trigger the sensor and cause a dash light to illuminate (and they all will at some point), the tractor must go to a dealer and the element in the cannister MUST be removed and cleaned (or replaced) in accordance with EPA approved procedure as the ash is considered a hazardous substance and must be disposed of correctly in an approved landfill. Therein lies the rub. If there is any damage to the substrate, the element must be replaced and you as the end user CANNOT replace it and/or reset the ECM to extinguish the light. Been my experience with big trucks, that at least 75% of the substrate elements have damage that precludes cleaning them so they must be replaced. Good part is, the element should not need renewed or cleaned for many rears under normal use. What normal use (definition) is is a crapshoot. I do know that Kubota says it's 1300 regens, other manufacturers, I have no idea.

Bottom line is, it's not a user serviceable item and the end user cannot reset the ECM either. If you keep the tractor long enough, you will have to have an authorized dealer perform the service.

No doubt that’s true. But it’s far enough in the future for my usage to be a negligible concern.