Extended idling vs switching on and off

[GManBart]

The manual for my Massey says the hour meter is set for one hour of running at 1500rpm equals one hour on the meter.

 

[DT86]

Here are a few questions for everyone to ponder...

How long do you idle a warm engine before shutting down. One minute, two minutes, ten minutes?

If you are leaving for "X" minutes and coming right back at what point in time does become "better" to just let it idle along vs shutting down?

 

[arlen4720]

I have checked my Kubota L5740 and Cat 301.8 which together moving material. The Kubota idles while I fill my dump trailer with the 301.8. The 301.8 idles while the L5740 is hauling the load. Both register the same number of hours used at the end of the day - the time from start up until shut down. The Cat I can figure out from the wiring diagram - it has an oil pressure switch set to close at 5 psi so the hour meter registers hours when the key switch is on and the engine oil pressure is over 5 psi. The Kubota I have no idea. The WSM says the Electronic Instrument Panel receives inputs from multiple sensors and switches, has multiple ECU's that output to the display. It doesn't say what triggers engine hours but it does not have an oil pressure switch like the Cat; however, it registers an hour running at high idle same as an hour running at low idle. Others, I can't say. Our JD 7720, 6230, and NH TS115A all display hours, not hours at PTO rpm, verified by measuring idle time. Same thing with our International combine. Older tractors we had did registers hours at PTO rpm, but all of them were cable tachs.

My 4720 has 3 hour meters...1 for engine run time (any RPM), 1 for PTO On Time, and 1 for forward or reverse motion time. So I guess you could take total engine run time, and back out the other 2 and find idling time. I will do that and report back. I might surprise myself with the amount of idling that I do (hopefully in a good way).

 

[dave1949]

Here are a few questions for everyone to ponder...

How long do you idle a warm engine before shutting down. One minute, two minutes, ten minutes?

If you are leaving for "X" minutes and coming right back at what point in time does become "better" to just let it idle along vs shutting down?

About the only time my tractor sees an extended period of high load is blowing deep snow. I never go directly from blowing snow to parked in the shed, so I consider it cooled off enough after potting around moving a bit of snow with the FEL, plus idling while I clean snow off the blower and bucket, to put it away and shut it off.

In the summer the tractor gets an easy ride back to the shed, 1700-1800 rpms, low enough gear the engine isn't "working." It doesn't need any idling before I shut if off IMO.

In general, if I'm doing something off the tractor for 5 or less minutes, I let it run.

 

[def]

Found an item on a trucker's forum - what is the longest you have let your engine idle. Many said no more than 10 minutes. Longest one I saw was 2 years, a person who bought a used diesel pickup, found it hard to start, so just let it run until he traded it off 2 years later. Many in northern climes said they let theirs run all winter, cheaper to use their sleeper and pay the fuel bill than get a hotel room. Even guys who have gone out to ND to get oil field jobs, can't find housing, so live in their truck and never shut it down all winter. Lots of questions asked about cylinder wash down, carbon buildup, etc. Everyone had heard about it, nobody had experienced a problem.

If you buy your tractors new you will always know how it was used. If you buy used -- will you know?

I'll bet oil changes were a bit messy....

 

[Blade Breaker]

Found an item on a trucker's forum - what is the longest you have let your engine idle. Many said no more than 10 minutes. Longest one I saw was 2 years, a person who bought a used diesel pickup, found it hard to start, so just let it run until he traded it off 2 years later. Many in northern climes said they let theirs run all winter, cheaper to use their sleeper and pay the fuel bill than get a hotel room. Even guys who have gone out to ND to get oil field jobs, can't find housing, so live in their truck and never shut it down all winter. Lots of questions asked about cylinder wash down, carbon buildup, etc. Everyone had heard about it, nobody had experienced a problem.

If you buy your tractors new you will always know how it was used. If you buy used -- will you know?

Just like a Sasquatch. Everyone has heard about them but no one has ever seen one. Except maybe this guy.

 

[DeereMann]

Here are a few questions for everyone to ponder...

How long do you idle a warm engine before shutting down. One minute, two minutes, ten minutes?

If you are leaving for "X" minutes and coming right back at what point in time does become "better" to just let it idle along vs shutting down?

Good point, DT86 -

Cummins recommends 2-5 minutes after hot run (turbocharged). In general, that's a max limit. Cummins also recommends not running an engine without at least 30% load on it. This is for MECHANICAL engines like most of hours.

Electronic, high pressure injection engines are not subject to the same rules. They don't wet-stack, clog injectors, dilute oil with fuel, or varnish injectors like mechanical engines can.

 

[CobyRupert]

:2cents:

I noticed (when looking for info on when was the last time the missing (fly-by-wire) Boeing 777 was "brought into the shop" for "maintenance") that planes age is noted by BOTH hours and cycles. i.e.: When predicting when a part is going to fail both are important.
Questions then becomes what is a good balance between the numbers, or what importance to put on one number compared to the other. Or conversely, that 1 number alone doesn't provide a good context. Sort of like miles on a car/truck doesn't really mean anything.
I'm in the limit the cycles, sacrifice the hours camp (to an extent). (Think about when you turn off an engine and hear the "tick-tick-tick" of metal on metal contracting, that must of previously expanded ) IMO, the expansion/contraction cycling of bearings, or heads on block, pistons, rings, etc, etc..is as detrimental as no load wear when it comes to the long term life of that part, especially if you have good clean oil.

p.s. it's sort of hard to find info on initial reports on how the B777 was brought into the hanger 12 days before it disappeared. Down the memory hole.

 

[joeu235]

I operated a Fairbanks Morse 38 8-1/8 diesel engine on a submarine back when I was in the Navy. 2400 HP monster. The thing was designed to run loaded for days at a time when there was an issue with the nuclear reactor When we were running drills and only used the engine for short intervals, it would carbon up and require a lot of maintenance. Also, procedure was to let it idle down for 20 minutes (unless you were about to be torpedoed).

The 4020 we have gets used for feeding round bales all winter. Putting around for 30 minutes and then back in the barn. Then the first time the chisel plow is hooked up and sunk the the ground, you can see sparks coming out of the exhaust from carbon.

The manual for the 317 skid steer says two relevant things: let the hydraulic fluid warm up before working it hard, and let the turbo cool down for 10 minutes after working it hard.