safe engine rpm "window" difference gear vs hydro

[TripleR]

I remember reading years ago, "Lugging an engine can't hurt it, over revving can." Is this no longer a valid statement? Can you harm a diesel engine by lugging it?

http://www.tractorbynet.com/forums/owning-operating/177801-lugging-diesel-engine.html

 

[heviduty]

Well, there you go. I have never had mine so slow that it runs rough like many of the posts in the link describe. At some point under 1000 rpm, the power just seems to die off and it quietens down, sort of like calming down. At that point I have no choice but to back off. Probably shouldn't let it get that slow. Thanks for the information. You learn something everyday if you pay attention.

 

[jenkinsph]

I run my tractors from about 1200 to 1800 rpm for most tasks, when working harder I speed them up. I don't find it necessary to run all pto implements at full speed either.

About that dealer saying you have to run a hydro at 540 pto speed hogwash, wonder if he even owns a tractor. There are lots of salesmen with little knowledge of the products they sell.

 

[madmax12]

I run my tractors from about 1200 to 1800 rpm for most tasks, when working harder I speed them up. I don't find it necessary to run all pto implements at full speed either.

About that dealer saying you have to run a hydro at 540 pto speed hogwash, wonder if he even owns a tractor. There are lots of salesmen with little knowledge of the products they sell.

That dealer actually got back to me, after I started this thread.

I had re-reviewed the operator's manual, at his suggestion. I left him a message saying the manual said nothing about a difference in rpm gear/hydro. He then reread the manual, and in humility, said what he had been taught years ago, may not be true after all.

He said I might have taught him something today.

I informed him that if I taught him anything about a tractor... it was purely by accident. :newhere:

This forum, and all you guys, ...amazing. Thanks for all of your input.

Hijack away, and let the learning continue! :thumbsup::drink::thumbsup:

 

[aczlan]

I run my tractors from about 1200 to 1800 rpm for most tasks, when working harder I speed them up. I don't find it necessary to run all pto implements at full speed either.

Agree. If I am running a mower (cutting hay or long grass) I will run at PTO RPMs, same with the baler, but otherwise, I run at whatever is needed (keeping above the "vibration zone" and not lugging).
For example, when tedding hay (with a basket style tedder), I like to run with the PTO between 300 and 400 RPMs and the L3830 in a relatively high gear (9th to 11th) to move through the hay quickly and reduce leaf loss.

About that dealer saying you have to run a hydro at 540 pto speed hogwash, wonder if he even owns a tractor. There are lots of salesmen with little knowledge of the products they sell.

Ayep. On our BX2660 it is almost painful to run at full throttle due to the hydro whine bouncing off of the roof of the cab.

Aaron Z

 

[texasjohn]

IMHO, the HST can take it. I run at RPM that is lowest needed to comfortably do the task at hand. "Comfortably" means considering forward speed, roughness of ride, safety, FEL/3PH responsiveness, PTO load/performance, etc. Should it bog down, I back off pedal and/or increase throttle. When I get in the seat, I typically do a multitude of different tasks and thus will adjust RPMs dozens of times in a half day's work.

The tractor and throttle are there to be used. I do.

 

[94BULLITT]

For example a small tractor like your max @ 2500rpm will suck .75 gal per hour operating at 2000 rpm's you me be down to .6 gph, so there is not that much of a noticeable difference or a big savings by operating at a lower rpm. That was just a example I don't really know what your fuel consumption is.

 

[SSdoxie]

There is no defined minimum operating RPM that I know of, each brand and model can be a little different. This is some risk to the HST if operating too low of RPM under load. The charge pump has to supply enough oil to replace oil lost through lubrication. The high the working/drive pressure in the HST, the more oil is pushed through the lubrication clearances regardless of RPM, so if charge pump is not spinning fast enough it could loose lubrication. An indicator of when charge volume/pressure is low is when the pedal feels sluggish. Personally, I run mine about 1500 at the lowest when puttsing around and 1800 using the loader. Most of the the time I'm at 2000 RPM or over.

 

[jenkinsph]

Something else I would add is that using the 4520 with Auto Throttle pretty much eliminates the need to even use the manual throttle in my grading work. About the only time I touch the manual throttle is when running the MX6 cutter or 673 tiller, all the landplane, boxblade and raking is done with the auto throttle.

On the 110tlb trying to do loader work with the throttle above 1800 results in the fel moving too rapidly to have much control of it, how fast I run will depend on how much and how great the distance is transporting material. I attribute this to the larger capacity hydraulic pumps on this model compared to a 3000 or 4000 series compact tractor.

 

[madmax12]

There is no defined minimum operating RPM that I know of, each brand and model can be a little different. This is some risk to the HST if operating too low of RPM under load. The charge pump has to supply enough oil to replace oil lost through lubrication. The high the working/drive pressure in the HST, the more oil is pushed through the lubrication clearances regardless of RPM, so if charge pump is not spinning fast enough it could loose lubrication. An indicator of when charge volume/pressure is low is when the pedal feels sluggish. Personally, I run mine about 1500 at the lowest when puttsing around and 1800 using the loader. Most of the the time I'm at 2000 RPM or over.

So, perhaps there is a slight important difference. Your description resembles the experienced dealers concern. He was very surprised to find no mention of this in operator manual.

Thank you for your very detailed explanation.

 

[madmax12]

Something else I would add is that using the 4520 with Auto Throttle pretty much eliminates the need to even use the manual throttle in my grading work. About the only time I touch the manual throttle is when running the MX6 cutter or 673 tiller, all the landplane, boxblade and raking is done with the auto throttle.

On the 110tlb trying to do loader work with the throttle above 1800 results in the fel moving too rapidly to have much control of it, how fast I run will depend on how much and how great the distance is transporting material. I attribute this to the larger capacity hydraulic pumps on this model compared to a 3000 or 4000 series compact tractor.

Yes, you, and I think it was 94bullit, both mention the auto throttle. I have never seen that, but it sounds interesting.

 

[madmax12]

I really appreciate all of your responses. I'm going to have to experiment (in warm weather) with proper rpm for various tasks...but be very careful to not strain the motor. If I understand the general consensus, here, if the motor sounds fine/normal at a low rpm, than its probably an ok rpm. If the motor or hydrolics seem at all sluggish, the rpm is too low.

In the winter, if I understand the manual, I should just leave the rpms up, because the engine temp needs to be up.

So, low rpms would be a warm weather "game."

Do the auto throttles keep the rpms higher, automatically, in cold weather???

 

[jenkinsph]

madmax,
The auto throttle does not keep the rpms' higher in cold weather. Bear in mind that everything is relative, I wouldn't get on a cold machine and speed it up before it has had a chance to warm up some, better to crank up to about 1200 to 1500 rpm and increase it gradually after a few minutes. Another point is to understand the difference between lugging the motor and loading the motor, you can hear the motor load down some while working the tractor, that doesn't constitute lugging the motor, there is a big difference. Loading the motor within it's design specs is actually the best choice. Lugging the motor and having the rpm's fall off dramatically without it being able to resume normal operating speeds is harmful and should be avoided. You have to be able to distinguish the difference between the two.

 

[madmax12]

madmax,
The auto throttle does not keep the rpms' higher in cold weather. Bear in mind that everything is relative, I wouldn't get on a cold machine and speed it up before it has had a chance to warm up some, better to crank up to about 1200 to 1500 rpm and increase it gradually after a few minutes. Another point is to understand the difference between lugging the motor and loading the motor, you can hear the motor load down some while working the tractor, that doesn't constitute lugging the motor, there is a big difference. Loading the motor within it's design specs is actually the best choice. Lugging the motor and having the rpm's fall off dramatically without it being able to resume normal operating speeds is harmful and should be avoided. You have to be able to distinguish the difference between the two.

I think I understand what u r saying.

I wonder if there is a youtube video demonstrating the difference (on an HST tractor), between lugging or loading.

Seeing/hearing it would be a helpful way for me to really grasp what we are discussing.

Thanks for your detailed explanation.

 

[TripleR]

I think I understand what u r saying.

I wonder if there is a youtube video demonstrating the difference (on an HST tractor), between lugging or loading.

Seeing/hearing it would be a helpful way for me to really grasp what we are discussing.

Thanks for your detailed explanation.

You really can't get much better explanation than the one by jenkinsph "Lugging the motor and having the rpm's fall off dramatically without it being able to resume normal operating speeds is harmful and should be avoided."

If you can't maintain or increase your RPM's by bumping up your throttle, it is lugging or close enough for me to call it lugging, so I let off the HST pedal or change ranges.

 

[madmax12]

You really can't get much better explanation than the one by jenkinsph "Lugging the motor and having the rpm's fall off dramatically without it being able to resume normal operating speeds is harmful and should be avoided."

If you can't maintain or increase your RPM's by bumping up your throttle, it is lugging or close enough for me to call it lugging, so I let off the HST pedal or change ranges.

No doubt, the explanations here are really great.

Based upon the thread, I'm quite sure I haven't lugged the motor.

Before my conversation with the other dealer, a couple of days ago, I really had no concerns. I was comfortable with how I was handling the machine, etc. When he raised his point, it got me wondering. That's the reason for the thread. Like many here, I've been around many machines, big and small, for decades. BUT, I have never had an HST...anything. SO... I'm trying to make sure I understand it completely. That's all.

People learn different ways, and YouTube has videos about almost everything... so that was just a thought.

Thanks for all of your guidance.

 

[CompactTractorFan]

Well of course you are right, but I think the bigger point is not the specific RPM you should or could operate at, it is that if your tractor is not lugging down, and you are putting a light load on it, you could safely operate it at something less than the rated 540 setting.. I think that is what we are trying to get across.

True, but it is still confusing when you read a thread like and everyone is going "well, I operate at xxxx RPM". :thumbsup:

I thought that is what I said in my response as we use a BX2660, L5740 and M8540, so you operate at the RPM's that work well for you HST or geared.

Oh, I'm sorry. I must have missed that. :ashamed:

 

[94BULLITT]

Yes, you, and I think it was 94bullit, both mention the auto throttle. I have never seen that, but it sounds interesting.

I made a video showing the auto throttle and the hst+ in the L4240. It's pretty crappy but here is the link.

Kubota L4240 HSTC Overview of HST + and auto throttle - YouTube

 

[madmax12]

That was great! After watching yours, there was a deenimplement video of grand L HST plus (12 minutes)...
Wow, that's a lot of automatic everything!!!

In the deenimplement video, they used the engine stall switch setting under load... It was hard to tell if I heard the engine slowing drastically or the HST whining/working harder. The implication, in the video, was that it may not be uncommon for someone to stall out a tractor (if they don't know what they are doing or they aren't paying attention). I have never come close to anything like that. For the life of my tractor, I believe it will be very lightly worked.

My Mahindra Max is less impressed with itself, after seeing all the bells and whistles available on the grand L. That is really cool!

Thank-you 94bullit!!!

 

[94BULLITT]

That was great! After watching yours, there was a deenimplement video of grand L HST plus (12 minutes)...
Wow, that's a lot of automatic everything!!!

In the deenimplement video, they used the engine stall switch setting under load... It was hard to tell if I heard the engine slowing drastically or the HST whining/working harder. The implication, in the video, was that it may not be uncommon for someone to stall out a tractor (if they don't know what they are doing or they aren't paying attention). I have never come close to anything like that. For the life of my tractor, I believe it will be very lightly worked.

My Mahindra Max is less impressed with itself, after seeing all the bells and whistles available on the grand L. That is really cool!

Thank-you 94bullit!!!

Thanks, its hard to tell what the different settings do unless you are the one in the tractor or maybe if I had a outside view.