Shut Down or Leave it Running Loading FEL

[Bird]

<font color=blue>idling a desiel is bad</font color=blue>

Steelfan, this topic has been discussed at length in the past, but I don't know whether I could find the old threads or not. However, I think the consensus of opinion (and my own) is that slow idling for extended periods of time does have some detrimental effects, but if you'll bump the RPM up to a fast idle, say 1200 to 1500 RPM, no problem unless you count the little bit of fuel you'll use.

 

[Gary_in_Indiana]

I'm with Bird on this one. Working for GM years ago I remember seeing all of the available data on gas vs. diesel for usages such as delivery vehicles. The diesel was clearly superior BECAUSE of the ability of the diesel engine to idle for hours with no ill effects. If a diesel can idle all day between short runs while making bread or milk deliveries to grocery stores, I'm sure it can stand a few minutes at idle while I'm off the seat loading the bucket. I hope this helps. /w3tcompact/icons/smile.gif

 

[Golfgar4]

<font color=blue>"...but if you'll bump the RPM up to a fast idle, say 1200 to 1500 RPM, no problem unless you count the little bit of fuel you'll use."</font color=blue>

Bird, you're absolutely correct. Back in the mid to late 70's, I drove over the road coaches for a private charter company. All of the buses were equipped with a fast idle switch, that when activated, bumped the idle RPM's up to around 1300. Our standing orders were if we were going to be parked for 6 hours or less, we left the engines running on fast idle, but every hour, we would shut the fast idle off and rev the engine for a minute or two. Anything over 6 hours parked, they left it to our discretion as to whether we shut down or not, depending on outside temperatures, etc.

I did ask why they wanted us to idle for so long, thinking that it was wasting fuel. The answer they gave me was that it took more fuel to start the engine than what would be burned when idling for 6 hours.

 

[Anonymous Poster]

Well lets add some fuel to the fire. About 6 months ago there was an article in Proggressive Farmer about excessive idling. Cummins and Cat were contacted and their advice went like this. NEVER idle more than 5 minutes at low idle. The opinions were that as the engine cools down, because it burns so little fuel at idle, combustion becomes imcomplete and the engine oil becomes contaminated etc. Their advice was go to fast idle if idling was necessary. A point to remember, some of the newer engines have a fast idle setting and some are to have an automatic fast idle in the future. Hope this muddies the water. For me, I don't idle more than 5 minutes.
Happy Tractorin'
Greg H

 

[Kodiak]

Golfgar4:
Yes this was and still is a preferred procedure, for older larger deisels especially if they were equipped with turbochargers. This was in the days before they started to intercool the turbochargers. Number one the turbocharger would start to overheat as it wasn't receiving enough cool air, this led to led to some pretty spectacular premature failures. And second it could cause the injector pump and injectors to load up, occasionally causing a breif engine run away. Detroit deisels were famous for this.
With our smaller non turbo equipped engines theres little chance of these situations occurring. In fact if you've been working it hard its usually good to let it idle for five minutes or so to bring the temperature down before shutting them off.

 

[Golfgar4]

Yeah, Russ, like I said, this was back in the '70's (OOOOO, that doesn't sound good when I put it that way/w3tcompact/icons/crazy.gif), and we were running Detroit's in the coaches. I wasn't a mechanic, so I just did as I was told, and was glad to do it on really hot (AC worked) or cold (heat worked) days! /w3tcompact/icons/wink.gif You ain't lived 'til you get to sit (and sleep) on a bus all day long! /w3tcompact/icons/frown.gif

 

[Bird]

Yep, things do change. I remember when we were using a brand new city bus in '67 (advertising gimmick) and letting it sit and idle all day with the air-conditioning running and the first day it ran too hot, so they made up a little rod to put on the throttle linkage when we parked it to hold the throttle open for a fast idle, and no more problems. Been too long ago to say for absolutely sure, but I think it was a two stroke Perkins diesel. In most cases, too slow an idle means too cool an engine in a diesel, but I guess nothing could be too cool in the middle of Dallas in the middle of the summer./w3tcompact/icons/frown.gif My brother's tool truck with a Cat diesel ran 10-12 hours a day, mostly idling, and it had a knob under the dash to speed up the idle in the winter so the heater would put out enough heat, but he didn't use it in the summer; just let it idle slow.

 

[Kodiak]

Garry:

Back in 82 I had a nice little 38' salmon boat up in Alaska. Made the mistake of letting the Detroit 6V71 in it, idle for two hours one evening. When the fish started jumping and I hit the thottle, there was a nice whoosh followed by pretty spectacular stack fire for a while. The second season I had that engine, one of the crew let it idle for several hours, that time he hit the throttle and the turbo exploded like a handgrenade. Needless to say it didn't take me long to scrap that Detroit for a non turbo Volvo.

 

[frank_f15]

IN the winter i will let it run, when i take a break , but in the summer i go by the 5 min. rule, if i figure to be off longer than 5 min. i shut it down, don't think it really makes a difference.

 

[Carl_NH]

Kent,

Been out digiing more stuff tonight and getting ready for the 16yds of topsoil in the AM to finish this project. As I have read there are more relevant discussions to follow. Thanks for the comment, I like the unit.

Carl