I just did a topic about fuel usage, but on another forum there were a number of comments about problems created by idling.
What's the damage I'm going to do by idling my 6V92 overnight, keeping the oil pressure above 25?
Thoughts?
A lot of truckers used to leave their 6V92 engines running all night at truck stops and rest areas before APU's became popular and they never seemed to have any problems. The old Ice Road truckers never shut their trucks down if left outside. But then again, they may be paying a price that is worth it to them to prevent them from freezing up. But I am very interested to hear what others have to say about this.
When I drove tour buses we would always leave them run at night. We would drop off all the old ladies and the park the bus at the motel. The buses often wouldn't start cold and they were hard to warm up the interior, so it was policy to leave them run. I don't remember if we used high idle or not... probably did.
But now I hear it's bad for the engine, etc.
Dave
Running any engine is bad for it. :-) I have seen army engines that have been in crates for 50 years start right up the first time. ;D Every running hour is one less hour you have before it needs to be rebuilt. However as in your case with needing to keep the bus warm for the passengers and to prevent the engine from starting hard in the morning or not starting at all, the trade off is worth it. But would I leave my bus idling while parked for a month in storage in southern California? Probably not. Everything in life is a trade off.
lol...i'm sure everyone is tired of hearing about the Arctic...many were started in October and shutoff in April...
I would much rather run my generator all night than my bus. I"m not sure the reason for running it all night unless a person doesn't have a generator and it's freezing out.
We used to run them on fast idle all night if it was in the -30s. They all had radiator shutters so they didn't run too cold.
Now a days, most buses and trucks have coolant heaters (Webasto), or APU, or in our conversions generators. Like Branderson said, running the generator with the block heaters on would be much better.
JC
Idling doesn't keep the engine hot enough and you get carbon deposits and other problems related to cold running.
I know some heavy equipment operators up North who would let the engines idle at full rpm, like 2200, to keep them warm enough.
And like eagle says, it is all winter. It is like you put on the long johns on Labor day and take them off May 24th weekend. By then they stand up by themselves...
JC
My little claim to somewhat fame was driving a turbo charged Jake equipped high altitude 4104 from Yosemite Valley up over Tioga Pass to Reno. Yosemite Park and Curry Company. Parked the night, then reversed course.
Occasional relief driver. Years were 1970 and 1971. Summers. The Pass was fun going up and down. Slow. The 4104 had an oil and coolant heater. The Motel had a dedicated 220 plug in. I was just 21. Long ago, far away. :)
Don't try it in California.>>>D
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 @$# off would be a emergency
So correct me if I'm wrong here, but with climate warming and greenhouse gasses we don't need to worry about wet-stacking anymore?
Running an engine uses fuel and makes wear.
Nobody cared back when fuel was cheap, and we didn't think much about the air.
That's all lovely until the cold weather comes along.
If you have no way to pre-heat the engine, it isn't going to start in the morning...
If you are able, leave the heat and the alternator for the engine and the batteries. Turn off the blowers/lights so everything goes back into the systems.
Idle it if you must, take the heat out of it if you must. There will be a smoke show on take off in the morning.
Busnut got to do what a busnut got to do.
And then get yourself better equipped for next year?
Happy coaching!
Buswarrior
I've done a lot of engine idling in my life on four strokes. But when I got the MC5 with the half worn out 8V71 I discovered that idling had some unwanted outcomes. Not sure about how it affected the oil ?? but for sure the normally dry slobber tubes started to drool and the exhaust got more acrid. So I learned to use the block heater (either with the generator or plugging in) and start it up and drive it.
Depending on how worn out your 6V92 is I think extended idling is not helpful to the engine. And for sure if you're going to idle it I would run it on high idle.
Fred
Not good to idle a 2 stroke Detroit all night. On fast idle around 1,000rpm-better. But you'll burn nearly 2 gallons an hour at 1,000rpm.
Quote from: luvrbus on January 12, 2018, 02:44:46 PM
All states have the 5 to 10 minute idle law, all states wave the fines and law if it is a emergency seems like freezing your @$# off would be a emergency
There are about 20 states that do not have anti idling laws. Minnesota is one such state.
Quote from: belfert on January 13, 2018, 08:45:33 PM
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
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.
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
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... :)
Quote from: luvrbus on January 14, 2018, 03:58:18 AM
:
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.
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.
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
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
Quote from: Dreadnought on January 15, 2018, 02:59:06 PM
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
Quote from: luvrbus on January 15, 2018, 07:41:04 PM
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
Quote from: Iceni John on January 15, 2018, 08:25:07 PM
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,
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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Diesel or gas generator running and providing electricity for your block heater.
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.
Quote from: Iceni John on January 15, 2018, 08:25:07 PM
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
Yes- and someone's put these catch cans on mine. Regardless- I've had my engine blip and run away a bit after prolonged idle- sounding really clattery while the oil burned off.
The other point I SHOULD have mentioned is that obviously Detroit knew about this and that in the myriad applications of this engine idle may be required (like in the example above)- which is why they fitted the fast idle circuit where it probably scavenges a lot better.
So after idling all night, we drove away....I had quite the puddle of oil underneath...and boy oh boy I wish I had taken a video of the exhaust when I took off down the road....let's just say I'm pretty sure no one saw the sun shine that day anywhere in the state....even though it was a clear day...
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Quote from: Dreadnought on January 19, 2018, 06:24:22 PM
Yes- and someone's put these catch cans on mine. Regardless- I've had my engine blip and run away a bit after prolonged idle- sounding really clattery while the oil burned off.
The other point I SHOULD have mentioned is that obviously Detroit knew about this and that in the myriad applications of this engine idle may be required (like in the example above)- which is why they fitted the fast idle circuit where it probably scavenges a lot better.
The 9-89 edition of Detroit's Operator's Guide for Series 53, 71 and 92 states on page 7:
Avoid Unnecessary Idling
During long engine operating periods, the engine coolant temperature will fall below the normal operating range. The incomplete combustion of fuel in a cold engine will cause crankcase dilution, formation of lacquer or gummy deposits on the valves, pistons and rings, and rapid accumulation of sludge in the engine. When prolonged engine idling is necessary, maintain at least 800 RPM.
John
So in other words close your shutters and idle away :)
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Just like every 2 stroke in the truck stop back in the day.
We just didn't notice, since the trucks rolled coal while they moved too...
happy coaching!
buswarrior
Quote from: Scott & Heather on January 21, 2018, 09:25:47 AM
So after idling all night, we drove away....I had quite the puddle of oil underneath...and boy oh boy I wish I had taken a video of the exhaust when I took off down the road....let's just say I'm pretty sure no one saw the sun shine that day anywhere in the state....even though it was a clear day...
Quote from: buswarrior on January 21, 2018, 05:08:27 PM
Just like every 2 stroke in the truck stop back in the day.
We just didn't notice, since the trucks rolled coal while they moved too...
happy coaching!
buswarrior
Years ago when I worked for a small truck line ,we had an old L J that rolled coal every time we changed gears.Used to be our only amusement since there were no radios,no stereo's or C B 's,to find some body walking along side the road, time it just right when the exhaust pipe was even with them and change a gear'. Boy!!We were a mean bunch back in those days!!!lol
Something that happens when idling the 2-stroke Detroit is that you have very little oil pressure at 500-600 rpms. The last thing to get oil are the rocker arms. I
Excessive idling wears out the rocker arms pins from lack of oil and of course there go your clearances.
Great advice Geoff thanks.