Service intervals, why are they different?

[STx]

I've got a 40HP NH tractor and a 20ish HP Deere mini-ex. The service interval for oil, etc. on the tractor is 100 hours and on the mini-ex it's 250 hours. Why the difference? Both are small diesels, the mini-ex runs at full throttle most of the time and the tractor runs at varying throttle positions depending on the work it's doing, I'd think that the mini-ex would need the shorter service interval, not the tractor.

Just curious if anyone knows the logic behind this.

 

[LD1]

Varying throttle / load is harder on the stuff than continuous load / speed.

Whats the filtration systems like?
Whats the oil capacity differences between the engines and hydraulics?

 

[STx]

The NH holds 5ish quarts, the Deere holds a little over 3 quarts, both have a single smallish oil filter.

The hydraulic fluid on the NH (about 8 gallons) is supposed to be changed every 800 hours and on the Deere (a little over 5 gallons), it's recommended to be every 2,000 hours. There are 2 hydraulic filters on the NH, the main and they hydrostatic transmission. The Deere only has one but, it's pretty large.

 

[IH782]

The best thing you can do for an engine is run it a high speed and never shut it off. California Highway Patrol cars are run 24/7 and are run hard, they get 200,000 plus thousand miles out of them and the engines usually have very little wear when torn down. The worst thing you can do for an engine is never get it up to temperature and let it idle for long periods, among other things.

 

[GManBart]

The best thing you can do for an engine is run it a high speed and never shut it off. California Highway Patrol cars are run 24/7 and are run hard, they get 200,000 plus thousand miles out of them and the engines usually have very little wear when torn down. The worst thing you can do for an engine is never get it up to temperature and let it idle for long periods, among other things.

I don't know where you got any of this, but it's pretty much all false. CHP cars, and most other state police/highway patrol, are usually replaced at the 100,000mi mark. Law enforcement warranties on vehicles tend to average 5 years and 100K. CHP had a hiccup in their vehicle replacement policy in the last 5 years, and their expenses skyrocketed, to the point where they were spending hundreds of thousands of dollars a month to maintain vehicles no longer in warranty (they have something over 2K vehicles). They went through a new vehicle selection process last year and ordered something like 500 new vehicles, to get their fleet back under control.

Further, highway patrol cars don't run at constant RPM at all. They idle for a while, go to max power, idle for a while, go to max power, etc. They don't spend much time running down the highway because they normally stay within a pretty small area on any given day.

Running an engine at "high speed" is a relative term. Diesel engines, like the one in his mini-ex, are restricted to an intentionally low RPM so they can last for many thousands of hours. They are essentially incredibly over-built. Gasoline car engines are different, and if you want to blow one up, all you have to do is run it near rated RPM continuously until something grenades....not even max RPM, just whatever max horsepower is rated at.

 

[IH782]

I don't know where you got any of this, but it's pretty much all false. CHP cars, and most other state police/highway patrol, are usually replaced at the 100,000mi mark. Law enforcement warranties on vehicles tend to average 5 years and 100K. CHP had a hiccup in their vehicle replacement policy in the last 5 years, and their expenses skyrocketed, to the point where they were spending hundreds of thousands of dollars a month to maintain vehicles no longer in warranty (they have something over 2K vehicles). They went through a new vehicle selection process last year and ordered something like 500 new vehicles, to get their fleet back under control.

Further, highway patrol cars don't run at constant RPM at all. They idle for a while, go to max power, idle for a while, go to max power, etc. They don't spend much time running down the highway because they normally stay within a pretty small area on any given day.

Running an engine at "high speed" is a relative term. Diesel engines, like the one in his mini-ex, are restricted to an intentionally low RPM so they can last for many thousands of hours. They are essentially incredibly over-built. Gasoline car engines are different, and if you want to blow one up, all you have to do is run it near rated RPM continuously until something grenades....not even max RPM, just whatever max horsepower is rated at.

Didn't say anything about warranty or how long they keep them. And small diesel excavators run the same RPM any other small diesel runs.

 

[LD1]

And small diesel excavators run the same RPM any other small diesel runs.

They are "rated and capable" of running the same RPM. Dont mean they have to.

And excavator is about as close as you can get to a constant speed and load as you can get. Thats good for parts, wear, oil, etc.

A tractor sees more varying loads and speeds....not as good for oil, wear, parts, etc.

 

[IH782]

They are "rated and capable" of running the same RPM. Dont mean they have to.

And excavator is about as close as you can get to a constant speed and load as you can get. Thats good for parts, wear, oil, etc.

A tractor sees more varying loads and speeds....not as good for oil, wear, parts, etc.

I was trying to point out that they are not "restricted to an intentionally low RPM".

 

[LD1]

Actually, both a tractor and excavator are BOTH restricted intentionally low.the engines are probably capable of double the rpms they are governed at. But by governing them allows them to run at WOT all day long and not blow up.take the same diesel engine,put it in a car or truck, and the HP and max RPM would likely be double+. But you cannot run that all day long and expect it to last

 

[STx]

Actually, both a tractor and excavator are BOTH restricted intentionally low.the engines are probably capable of double the rpms they are governed at. But by governing them allows them to run at WOT all day long and not blow up.take the same diesel engine,put it in a car or truck, and the HP and max RPM would likely be double+. But you cannot run that all day long and expect it to last

I don't know that this is entirely true. My NH is PTO speed at about 2600 RPM and redline starts at about 3100. My 7.3 turbo diesel in my F250 will do 80MPH at 2500 RPM and redlines about 3500 RPM so, they're pretty close to each other. I don't have a tach on the mini-ex so can't say for certain but, I'd say it sounds like it's about 2500 RPM when it's at operating speed. I've not had any high revving diesel engines, all of mine operate in that 2500 RPM range.