Running a Diesel at Idle

[deckofficer]

Originally Posted by Jim Cate

Wow,Mr B, you sure know some boss truckies, for that equates to about 2750 miles per day, or around 115 mph average 24 hours a day for six months.

That's TRUCKIN"... or maybe you just made up that "fact"?

Jim

Yeah Jim, I saw that and chuckled. I was an owner-operator and a busy year was 100,000 miles or as you computed, 11.4 mph 24/7/365.

I never got 3 to 5 million miles on an overhaul. My 2 stroke Detroits were ready for overhaul after 300K miles, Cummings around 500K miles, and the only Cat I had was the big one, 1693 TA OHC and ran it 750K before it was sold and run even more.

[Mr B]

Originally Posted by Jim Cate

Wow,Mr B, you sure know some boss truckies, for that equates to about 2750 miles per day, or around 115 mph average 24 hours a day for six months.

That's TRUCKIN"... or maybe you just made up that "fact"?

Jim

Thats what my mate told me, His 500,000 mile or six months warranty on his new Kenworth Louisville 9000, Had ran out on him, He does the miles. Its his income, If his truck is not moving, he's losing money,
Melbourne,Sydney, Brisbane, Perth and back to Melbourne, Thats 6 thousand miles, In a straight line, And takes about a week, He's home for almost a day, And then does it again,
How many miles he did, I dont care, Im just not interested in it, Its just what he told me, Knowing a lot of interstate truckers, They all do the same mileages,

But maintaining a diesel engine in peak performance, Is my only concern, I have quite a few diesels myself,
25 HP diesel Tractor, Various Diesel Mobile Welders, Any onsite Deisel equiptment that breaks down, I usually get it running again, Time is money, Broken equiptment doesnt earn money, My Pride and Joy,Oshkosh Diesel truck with 300 HP Caterpillar, I drive it now, I put 1200 miles on it in five days last week touring around, Sightseeing, 27 HP Diesel Westerbeke, in my Boat, 50 HP Diesel Tractor. Petrol motors, I have a heap of those too, I also pay 5 registrations,

I would rather buy an ex taxi and put up with the rattles, I do buy a reliable car, That was properly maintained,
Its also very rare for me to have a problem with any of my motors, And that is due usually to bad fuel coming in, Extra filters cure that problem, But they do need cleaning out more frequently,

Here, You blow a big diesel motor, Its going to cost between $12000 and $20000 to repair or replace,
You make sure your diesel is maintained properly,

Middle of the Ocean, Who cares if you blow a motor, You can sail home.
Blow a motor here in OZ, your probably 200 miles from the nearest anything, Been there, Done that, Its fix it on the spot, Or sit and wait till some one comes along, Then get a lift to the next town,
Your vehicle will be stripped by the time you get back to it, A couple of days later,

[eyschulman]

While idling may or may not be good for a marine diesel motor I doubt it has much to do with the average failures and long life. If you monitor the motor problems and responses by working mechanics on a site like boatdiesel.com, you will soon see that most failures are do to prop overloading ,cooling Sx problems and poor exhaust geometry. Turbos tend to fail from moisture and rapid spool-up without adequate lubrication , not idling.

[goboatingnow]

Originally Posted by zeehag

i am sooo glad i do not have a turbocharged diesel in either of my boats.i had turbo'd cars--sporty ones--- awesome fun---and much more difficult to manage in maintenance.. i prefer my good old semireliable at present perkins...or should i have called it my soon to again be somewhat reliable old perkins....
one thing for sure--it will be interestingly colorful. pix pending.

Modern turbocharged diesels have little in common with petrol engines. They are of course not indestructible and need to be inspected at about 2000 hours ( ie the turbo ) . Rebuilding is cheap enough.

Really no modern diesel can survive the regulations today without turbocharging.

Dave

[Stu Jackson]

Jesse's original question "defined" idling, in his (and my) Universal naturally aspirated engines, that 800-1200 rpm.

I can't get ANY charge out of an alternator at that rpm and need a minimum of 1500 rpm to get voltage high enough to start charging.

Otherwise, starting the engine make no sense.

A "load", albeit a small one, is the alternator for charging.

It is not, however, at the defined idle.

[S/V Alchemy]

I have always held that once you feed a diesel clean air, clean fuel and regularly cycled lubricants, it is happiest running at 75% or so power (say, 1900-2100 RPM) for hours and hours. This is usually the most economical use of diesel fuel as well.

I am less fond of idling the engine at 800-1000 RPM in neutral because it wastes fuel. If you need to charge batteries, there are cheaper methods (in the long run), or simply take the boat out for a run (and a pumpout beyond three miles, perhaps?) at the standard cruise settings. You'll make power and discourage a bit of growth at the same time.

[Jim Cate]

Originally Posted by Mr B

Thats what my mate told me, His 500,000 mile or six months warranty on his new Kenworth Louisville 9000, Had ran out on him, He does the miles. Its his income, If his truck is not moving, he's losing money,
Melbourne,Sydney, Brisbane, Perth and back to Melbourne, Thats 6 thousand miles, In a straight line, And takes about a week, He's home for almost a day, And then does it again,
How many miles he did, I dont care, Im just not interested in it, Its just what he told me, Knowing a lot of interstate truckers, They all do the same mileages,

Mr B, I'm surely in favour of good maintenance of diesel engines. What I am not in favour of is the posting of impossible "facts" to back up one's theories.

PErhaps you should ask your mate just how he managed to average well over 100 mph 24/7 for six months. I respect professional truckies, their skills and knowledge, but my BS alarm goes off for such statements.

Jim

[Surrymark]

From my diesel class with Jon Bardo at WoodenBoat:
• Sure, idling is not the best, but everybody does it.
• A diesel not under load is idling, no matter what the rpms.
• A battery won't charge any faster than the rate at which it discharged.
My takeaway is to run the engine at low rpms in reverse, when I am sure that the mooring or anchor will hold.

[MarkSF]

Originally Posted by Stu Jackson

Jesse's original question "defined" idling, in his (and my) Universal naturally aspirated engines, that 800-1200 rpm.

I can't get ANY charge out of an alternator at that rpm and need a minimum of 1500 rpm to get voltage high enough to start charging.

Otherwise, starting the engine make no sense.

A "load", albeit a small one, is the alternator for charging.

It is not, however, at the defined idle.

I have to "blip" the throttle to get the alternator to start charging, but then its OK down to 800 rpm. Something a bit funny about yours?

[Jd1]

Originally Posted by Surrymark

From my diesel class with Jon Bardo at WoodenBoat:
• A battery won't charge any faster than the rate at which it discharged.

Somebody is feeding you a bunch of horse apples!

[bobconnie]

If your alternator will not put out enough at 1200 rpms, your set up is wrong! IE miss matched pullys, to small of gen pully ect! If ya figure out the ratio ya need and set it up right, you can get good charge at 1200 rpms up ! We ran our old perkins at 1100 -1200 rpms in gear when we charged batts and made water, and pulled the freezer down for over 15 yrs, never had any problems! The perkins had over 10,000 hrs on it when we sold the boat, still ran well burned less then a QT in 100 hours never had to add oil between oil changes. We did have 3 major oil filters on it ! I think that really helped !Clean oil is king in my diesels.

[transmitterdan]

Several people in this thread have said truckers idle their diesels a lot. In the US and many other countries this is not true these days. Idling while parked is illegal in most states in the US. I believe it is the same in many EU countries too. It's not because states are worried about the engines. It's about pollution control.

[s/v Jedi]

I'm currently driving in NA with a coach that has a Cummins ISL 425hp, 8.9 liter engine. You're not supposed to idle it at all. You start and as soon as oil pressure is registered, you should either start driving or switch to high idle. The ECM can even switch to high idle itself during prolonged idling to preserve the engine.

When I fuel at a truck stop, parked trucks run their gensets, not their propulsion engine.

[chala]

Originally Posted by bobconnie

We ran our old perkins at 1100 -1200 rpms in gear when we charged batts

“1100 -1200 rpms in gear”, is not what I would call idling.

Originally Posted by chala

This explains to some extent why an alternator may cut-in at 1500 motor RPM. Lowering the speed of the motor may be detrimental to the belt if the alternator at that time is loaded to the full capacity of the belt.

Originally Posted by JK n Smitty

they idle for long, long, long hours.

Curious, reads like a tall story. Hard to imagine that in a productive country machinery will be kept running at idle for “long, long, long hours.” What for? Just to increase pollution, waste non-renewable energy, wear the machinery down and increase the fuel bill? Maine is having us on and must be .

Idling as always been the cause of problem with delivery truck engine where the truck engine was left idle during the unloading, loading of goods. For this reasons some trucks have a fast idle that suppose to minimise damage to the engine.

Idling speed: the lowest revolutions per minute as specified by the manufacturer.

[El Pinguino]

I alwys thought the issue was the 'load' not the 'revs' ..... run an engine at high revs no load = glazed bore.... low revs underload no problem... I often charge batts at just above minimum revs but you know when the alternator cuts in or out... starts at 60 amps most times... drops to 20 soon there after and then to 5 or so. You can tell what its doing without looking at the ammeter.
That's a Volvo MD17D with over 10k hours on it . Maybe the fact that I painted it 'Lister Green' a few years back took the curse off it.