What's wrong with idling?

[belfert]

All states have the 5 to 10 minute idle law, all states wave the fines and law if it is a emergency seems like freezing your @$# off would be a emergency     

There are about 20 states that do not have anti idling laws.  Minnesota is one such state.

[luvrbus]

There are about 20 states that do not have anti idling laws.  Minnesota is one such state.

:

In those states the cities have a ordinance against idling Minneapolis has a 5 minute idle law or did have   

[Jon]

More examples of laws written by people without a clue.

When temps get into the sub-zero range I will not shut off the engine, not only because I don't want to freeze, but also because if it cools down when shut off it is not going to start. But some lawmaker won't understand that.

[luvrbus]

About all buses made in the last 20 years have a diesel fired heating system now to pre heat a engine,you would be up the creek if it failed though 

[bevans6]

Every anti-idle law I've seen has exceptions for both hot and cold weather, so the argument that it won't start after an over-night cold soak is built in to that.  Needing the engine for heat or air conditioning ditto.  I think the main thing is that when a bus or truck is used as a tool to make money, running the engine is part of the built-in cost of doing business.  If you do a rebuild at 450K instead of 500K, that 50K of engine life is paid for by the work the engine did for you.  If you are a bus nut, the potential downside is bigger - the whole bus is an expense in the first place, so adding to that expense when you have cheaper options is just isn't a logical thing to do.  We often operate equipment that is, in the greater scheme of things, on it's last legs.  When the engine is failing, or close to that, idling for extended periods of time will cause it to start to do things you would really rather it didn't do, like spew black crap all over itself, the back of the bus and the car you tow.  Been there, done that, changed the engine... 

[belfert]

:

In those states the cities have a ordinance against idling Minneapolis has a 5 minute idle law or did have   

Yes, Minneapolis has an anti-idling ordinance, but there are 100+ other cities in Minneapolis metro area that have no such laws.  Two cities in one state is a far cry from stating that every state in the USA has anti-idling laws.  There may be at least one city in every state that has an anti-idling ordinance, but only about 30 of the 50 states have a blanket anti-idling law.  Law or not I generally don't idle my bus because it wastes fuel.

Many of the cold weather states have exemptions at extreme cold temperatures.

[Dreadnought]

If you leave your engine idling overnight you will get broken in and lynched by a bunch of Eco Warrior facists!

But seriously- on the Detroit 2 strokes- the scavenging of the blower is set up to scavenge well- or displace the combustion products in the cylinder -at higher rpm.
This is why if you labour the Detroit 2 stroke - esp the NA motors- it will smoke a little and where all the lore came about - about driving the detroits angry and changing up at higher rpm. Infact as a consequence of this- the better point BSFC or better engine fuel efficiency is at higher rpm compared to a 4 stroke.

So at idle the engine doesn't scavenge as well as at higher rpm. In extreme cases this can lead to 'ring jacking' where the compression rings get clogged with soot and could even lead to scoring. I've seen this on 2 stroke diesels before on the dyno.

Now on a Turbo charged Detroit you may be given a LITTLE leeway as the Turbo provides some boost at lower rpm compared to a NA and therefore scavenges a little better- but at idle you're asking for a lot.

The other aspect for 2 stroke  Detroits is that oil can gather up in the air boxes and this can lead to running away when you finally drive it.

[bigred]

Back when I drove buses late 60's through the 70's ,we Idled them a lot because we didn't know better.You have to remember ,all we had was the bus air and heat ,then later when I started following the SG music ,all the established groups had Eagles with a few Flex High Levels thrown in.The rest of us had to make do with old 3751's or if lucky maybe a 4104 .Back in those days it was not unusual to have six or seven groups .Those guys with the Eagles and Flexes would show up any where from twelve noon till five or six pm .If the weather was hot or cold those things would idle anywhere from six hours to ten or 12 hours .The only thing we worried about was making sure we had enough fuel to get us to a truck stop after the singing was over .Never a thought about any of those dreaded things that happens idling ,until I joined Bus Topics!!! Now I am so paranoid about letting mine idle that when I start to stop I hold the brake with one foot and the accelerator with the other one

[luvrbus]

I remember the 53 and 71 series in construction equipment the ones that got idled a lot were 4000 hrs max if you were lucky, the ones people ran the piss out of and shut it off were 8 to 10,000 hour engines

[Iceni John]

The other aspect for 2 stroke  Detroits is that oil can gather up in the air boxes and this can lead to running away when you finally drive it.

Shouldn't any accumulated oil in the airboxes simply drain out of the slo..er tubes, at least until their check valves close at about High Idle's airbox pressure?

John

[eagle19952]

I remember the 53 and 71 series in construction equipment the ones that got idled a lot were 4000 hrs max if you were lucky, the ones people ran the piss out of and shut it off were 8 to 10,000 hour engines

very true...idle for us was 1200 rpm.
600 rpm will/can kill one in very very short time...
on the cat trains (building drill pads and Herc strips) we towed dump trucks...5 to a D7.
in a 100 mile move, often 6-7 days (cat train) we would lose 5 out of 10 engines.
the start up routine was 5 drivers would engage 1 gear and the whole thing would move..then the driver would pull the throttle out and lock it and jump out...sometimes they wouldn't lock or whatever...1/2 dozen engines came in on the first Herc.
the engines got paid for at the gas pumps all over the USA this was about 1978--81

[eagle19952]

Shouldn't any accumulated oil in the airboxes simply drain out of the slo..er tubes, at least until their check valves close at about High Idle's airbox pressure?

John

if the engine doesn't run hot and the ambient is sub freezing, i have seen those tubes plug up like the oil turned to cured asphalt,

[Scott & Heather]

I don't idle mine much at all...but tonight I have to. We are leaving in the morning for Michigan and I can't take the chance of her not starting in the AM after a 16°F night...so I started her a little bit ago (was hard to get her going) and she's gonna idle until tomorrow morning when we leave.


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[chessie4905]

Diesel or gas generator running and providing electricity for your block heater.

[Brassman]

In my experience running a '71 at low loads coked up 3 of the 4 exhaust valve ports. That was on generators. With a bus, running down the road will blow the crud out -- but low loads on a 2-stroke ain't good.