Starting a diesel for only a few moments...Bad?

[dknoch]

I was always under the assumtion that starting a diesel for a very brief time was not good for the engine. I thought it gunks up injectors and valves and stuff. The reason I am asking is I work for a fire department and someone got this idea that all vehicles should be started in the morning just to make sure they will start. What ends up happening is the big Detroit 60s in our engine and ladder truck will start up and idle for about 30 seconds and be turned off right away. It has been argued that just because it starts now doesn't mean it will start next time. I was wondering what you guys think of this and if anybody has any data or articles stating that this is bad for the engine that I could show to the other members.



Thank you.

Dan Knoch

 

[HBarlow]

Like you, I think that is a very stupid idea and would never do it to my own equipment.

I don't know if it will cause deposits on injectors and other internal components but starting a large diesel engine and allowing it to run for only 30 seconds each day will slowly discharge the batteries so that in the event of a fire call the batteries may not be able to start the engine when it is needed.

Only someone who knows nothing about an engine would implement such a rule.

 

[CSkal]

I agree with Hbarlow in that it is not a good idea; I don't do it with my truck.

With that said, I assume that starting the fire truck once at the beginning of the day (or shift) is just supposed to be a quick "feel good" check to verify that there are no obvious major problems in evidence.

Can we assume that there will be no surprises like a Ford 6. 0?

 

[BSeyler]

Diesel engines like it best when run for prolonged periods of time. That's one of the big reasons Harvey had such good service from his when transporting. Short runs reduce a diesel engine's life.

Bud

 

[mwilson]

All Diesel Powered Fire Trucks in my town are started and driven at least 30 miles per week and brought up to operating temp using a combination of intown and open highway driving. They rotate the five trucks involved at the rate of one, sometimes two per evening so some trucks get a drive cycle twice a week.



Would never dream of doing what your fire department is doing.



Besides, don't you have the constant power and air supplies in place so that the batteries are at full charge and the air tanks are full so the maxi brakes can be released immediately??

That along with a drive cycle similar to my town should take care of it "not starting the next time"!!!!



It is not only for the benefit of the engine as a drive cycle will extend the life of the many seals involved with a Class 8 chassis such as wheel and pinion seals, etc.

 

[dknoch]

Thanks for the replies everybody. Yes, all of our equipment has battery chargers and air compressors to maintain battery charge and air brake charge. We run the stuff quite regularly but there are days were the 30 second run is all that vehicle runs for the day. I personally refuse to start the truck and simply check that the batteries are charging and that the air system is charged, or I will pull the truck out and run it in pump mode with the water circulating. Does anybody have anything in writing that I can show the "powers to be" that this is bad. I know somewhere there was an article about starting a 12 valve for a few moments and it had you running the throttle for a few minutes at a high idle to warm it up and cook off the gunk. I know things have changed and wonder if that still applies. On a personal note, if I need to move my truck a couple feet to get something out of the garage from behind the truck, I'll put in in neutral and roll it forward, but thats just me.

 

[mwilson]

Just checked Diesel GenSet Requirements as a comparison and the common rule seems to be 1/2 hour run times at full load so that all components are at operating temperature before shutting it down.

If I get a chance this afternoon I will call Cummins and see if I can score a PDF in regards to Diesel Engine run time as proof for your "higher-ups"!!!!! Maybe Cummins can offer a document that is fire truck specific, depends if I can catch up to the engine spec guy down there.

Will let you know.

 

[dknoch]

Hey, wow, that would be great. Yeah, i figure any info I can show them that this is bad so that this goofy practice is stopped. Thank you guys!

 

[WDixon27]

warms up everything just enough to make moisture but not burn it off, i hate it when someone starts a engine for a few seconds, my boss does that, i usually call it burning off excess battery charge and starter motor life because he'll do it several times

 

[Skydiver]

Not good !
Causes condensation which adds acidity to oil. The engine must come up to full operating temp to remove condensation. Wears out starter solenoid as well as other parts that require lubrication. I would say that once every 5 days for 20 minutes is much better. Remove the battery charger for 24 hours once every few months and the voltage should be 12. 4 to 12. 6. Do this with batteries isolated.
I once started (new battery) an old 60s diesel Ford tractor that sat for over 2 years with 4 revolutions. Went right work pulling a box blade. Only changed the oil after it warmed up.
Trust me, I know change is sometimes difficult at a FD.

 

[dknoch]

Thanks for all the good advise everybody. That last line about change being difficult is so true, I can't tell you how many times it is asked "why do we do it that way?" and the answer is "Because thats the way we always have. " Really, I work in a good place and they are always trying to do the best thing, it just takes a little work to change peoples minds sometimes.

 

[dknoch]

Borrowed from the pages of Wikipedia in regards to a diesel generator, however the same pricipals should apply to any diesel engine:

"Diesel engine damage due to misapplication or misuse of generating set

Diesel engines can suffer damage as a result of misapplication or misuse - namely internal glazing (occasionally referred to as bore glazing or piling) and carbon buildup. This is a common problem in generator sets caused by failure to follow application and operating guidelines. Ideally, diesel engines should be run at least 60-75% of their maximum rated load. Short periods of low load running are permissible providing the set is brought up to full load, or close to full load on a regular basis.



Internal glazing and carbon buildup is due to prolonged periods of running at low speeds and/or low loads. Such conditions may occur when an engine is left idling as a 'standby' generating unit, ready to run up when needed, (misuse); if the engine powering the set is over-powered (misapplication) for the load applied to it, causing the diesel unit to be under-loaded, or as is very often the case, when sets are started and run off load as a test (misuse).



Running an engine under low loads causes low cylinder pressures and consequent poor piston ring sealing since this relies on the gas pressure to force them against the oil film on the bores to form the seal. Low cylinder pressures causes poor combustion and resultant low combustion pressures and temperatures.



This poor combustion leads to soot formation and unburnt fuel residues which clogs and gums piston rings, which causes a further drop in sealing efficiency and exacerbates the initial low pressure. Glazing occurs when hot combustion gases blow past the now poorly-sealing piston rings, causing the lubricating oil on the cylinder walls to 'flash burn', creating an enamel-like glaze which smooths the bore and removes the effect of the intricate pattern of honing marks machined into the bore surface which are there to hold oil and return it to the crankcase via the scraper ring.



Hard carbon also forms from poor combustion and this is highly abrasive and scrapes the honing marks on the bores leading to bore polishing, which then leads to increased oil consumption (blue smoking) and yet further loss of pressure, since the oil film trapped in the honing marks is intended to maintain the piston seal and pressures.



Unburnt fuel then leaks past the piston rings and contaminates the lubricating oil. Poor combustion causes the injectors to become clogged with soot, causing further deterioration in combustion and black smoking.



The problem is increased further with the formation of acids in the engine oil caused by condensed water and combustion by-products which would normally boil off at higher temperatures. This acidic build-up in the lubricating oil causes slow but ultimately damaging wear to bearing surfaces.



This cycle of degradation means that the engine soon becomes irreversibly damaged and may not start at all and will no longer be able to reach full power when required.



Under-loaded running inevitably causes not only white smoke from unburnt fuel but over time will be joined by blue smoke of burnt lubricating oil leaking past the damaged piston rings, and black smoke caused by damaged injectors. This pollution is unacceptable to the authorities and neighbours.



Once glazing or carbon build up has occurred, it can only be cured by stripping down the engine and re-boring the cylinder bores, machining new honing marks and stripping, cleaning and de-coking combustion chambers, fuel injector nozzles and valves. If detected in the early stages, running an engine at maximum load to raise the internal pressures and temperatures allows the piston rings to scrape glaze off the bores and allows carbon buildup to be burnt off. However, if glazing has progressed to the stage where the piston rings have seized into their grooves, this will not have any effect.



The situation can be prevented by carefully selecting the generator set in accordance with manufacturers printed guidelines.



"For emergency only sets which are islanded, the emergency load is often only about 1/4 of the sets standby rating, this apparent over size being necessitated to be able to meet starting loads and minimising starting voltage drop. Hence the available load is not usually enough for load testing and again engine damage will result if this us used as the weekly or monthly load test. This situation can be dealt with by hiring in a load bank for regular testing, or installing a permanent load bank. Both these options cost money in terms of engine wear and fuel use but are better than the alternative of under loading the engine. For remote locations a Salt water rheostat can be readilly constructed.



Often the best solution in these cases will be to convert the set to parallel running and feed power into the grid, if available, once a month on load test, and or enrolling the set in utility Reserve Service type schemes, thereby gaining revenue from the fuel burnt. "

 

[Skydiver]

dknock, I'm very thankful for the performance of our fire chief. We have around 25 active members. Our chief makes 95% of the calls when he is not working. If a house fire gets called out, many times he will leave his job to assist. All for NO money.
He does not allow the bay tempature to drop below 62F in the winter. This uses many tons of propane. The use of block heaters would not be heard. He says the tankers and pumpers need to have some heat stored up should we have a call when below freezing which is true. We run 3 fire stations. 3 pumpers, 2 tankers (one 2000 gallon and one 3000) and two phord brush trucks. We hardly never get to use a hydrant on a working fire, just shuttle operations.
Just go along with the officers is my best advice. I would go behind them and run the trucks up to operating temp every 5 days. Remember that your trucks do see full throttle on a call, which is good after they get warmed up. I try to not go full throttle until I get a mile down the road. Our 3000 gallon tanker runs a cat 3208 w allison transmission and won't hardly get out of its own way. LOL
.
A preacher once told me that commanding a VFD is like hearding cats. So true.

 

[rbattelle]

I'm going to go a bit against the trend here and propose that this 30 second per day running of the engines is unlikely to do any measureable damage in the long term.



Yes, water is a product of combustion, but over a period of 30 seconds I doubt there's sufficient water generated to harm anything.



Yes, running under no load conditions won't permit sufficient heat build up to clear carbon deposits. However, how much carbon is being deposited in 30 seconds? Probably not much.



Naturally, all those extra start cycles will be a bit hard on batteries and starters.



How long has the department been doing this, and how many engines have failed as a direct result?



Ryan

 

[ChrisOlson]

I was always under the assumtion that starting a diesel for a very brief time was not good for the engine. I thought it gunks up injectors and valves and stuff. The reason I am asking is I work for a fire department and someone got this idea that all vehicles should be started in the morning just to make sure they will start. What ends up happening is the big Detroit 60s in our engine and ladder truck will start up and idle for about 30 seconds and be turned off right away. It has been argued that just because it starts now doesn't mean it will start next time. I was wondering what you guys think of this and if anybody has any data or articles stating that this is bad for the engine that I could show to the other members.



Thank you.

Dan Knoch

Tell us more about your trucks the Detroit 60 what year do they have the new regen exhaust and are there other types of engines you are concerned about



Does your fire dept keep the engines heated heat the oil? heat the Coolant??

while in STBY mode. do your engines have a pre lube system installed



Many varibles to talk about. However from personal experience we never run a diesel for only 30 seconds on a regular basis. Personally I would agree with you.



if you want to extend the life of a diesel keep it heated (coolant) Prelube it and post lube the turbo after the engine shuts down. ALL of our diesels on our ships have these systems in place.



hope this helps





chris

 

[ChrisOlson]

I'm going to go a bit against the trend here and propose that this 30 second per day running of the engines is unlikely to do any measureable damage in the long term.



Yes, water is a product of combustion, but over a period of 30 seconds I doubt there's sufficient water generated to harm anything.



Yes, running under no load conditions won't permit sufficient heat build up to clear carbon deposits. However, how much carbon is being deposited in 30 seconds? Probably not much.



Naturally, all those extra start cycles will be a bit hard on batteries and starters.



How long has the department been doing this, and how many engines have failed as a direct result?



Ryan

Also those extra cold Dry start cycles for 30 seconds will add extended wear due to lack of lubrication it takes many seconds for cold oil to reach those oil galleries and such. . I would not do it.



not tryiong to ruffle your feathers ryan.



chris

 

[dknoch]

About our trucks and department... We are an all full time department manned 24-7, we run EMS and fire out of 1 station, about 2000 calls per year, on the east side of Cleveland, Ohio. All our members are paramedics including our chief. First off, I want to let those of you who are volunteers know that I have nothing but respect for you guys and gals. About our trucks, we have two newer E-450 squads with 6. 0 diesels that I don't really worry about since they have the wheels ran off of them on a regular basis. Our engine is a 2003 E-one pumper with the Detroit 60. It sees a fair amount of use as it responds to all car accidents and wires down and all those kinds of calls. The truck I am most concerned with is our '97 Pierce 100' arial platform. Fantastic truck and stable as can be at 100'. It also has the Detroit 60 in it but it only really responds to alarms so it may be a couple days that this truck does not move. For a long time, it actually had almost a miss when you would pull it out cold at about 1500 rpms. This always seemed to go away after it would warm up and I haven't noticed it much recently, but I did make a point of running it up to temp periodically. As far as this practice of staring the trucks just to start them, about a year ago, someone made a check list of everything we should check in the morning and starting the truck was on the list. I will say this, I work with some of the best paramedics imaginable, but some of them don't know too much in regards to engines and trucks. Having a diesel pickup for the past 8 years and doing 90% of my own maintenance, they often look to me for advise and repairs of minor equipment. I know that if I can show some solid evidence, there would be no problem to have this practice changed.



Thank you all again,

Dan Knoch

 

[rbattelle]

Also those extra cold Dry start cycles for 30 seconds will add extended wear due to lack of lubrication it takes many seconds for cold oil to reach those oil galleries and such. . I would not do it.



not tryiong to ruffle your feathers ryan.

No ruffling at all. I just wanted to offer an alternative opinion. You're right about the lack of lubrication at startup.



I suppose the only way to know the effects for certain is to do it for a long time and see what happens.



Ryan

 

[HBarlow]

About our trucks and department... We are an all full time department manned 24-7, we run EMS and fire out of 1 station, about 2000 calls per year, on the east side of Cleveland, Ohio. All our members are paramedics including our chief. First off, I want to let those of you who are volunteers know that I have nothing but respect for you guys and gals. About our trucks, we have two newer E-450 squads with 6. 0 diesels that I don't really worry about since they have the wheels ran off of them on a regular basis. Our engine is a 2003 E-one pumper with the Detroit 60. It sees a fair amount of use as it responds to all car accidents and wires down and all those kinds of calls. The truck I am most concerned with is our '97 Pierce 100' arial platform. Fantastic truck and stable as can be at 100'. It also has the Detroit 60 in it but it only really responds to alarms so it may be a couple days that this truck does not move. For a long time, it actually had almost a miss when you would pull it out cold at about 1500 rpms. This always seemed to go away after it would warm up and I haven't noticed it much recently, but I did make a point of running it up to temp periodically. As far as this practice of staring the trucks just to start them, about a year ago, someone made a check list of everything we should check in the morning and starting the truck was on the list. I will say this, I work with some of the best paramedics imaginable, but some of them don't know too much in regards to engines and trucks. Having a diesel pickup for the past 8 years and doing 90% of my own maintenance, they often look to me for advise and repairs of minor equipment. I know that if I can show some solid evidence, there would be no problem to have this practice changed.

Thank you all again,
Dan Knoch

I am confident that Cummins, Inc. would respond if you asked about that practice regarding a Cummins engine. I'm equally confident they won't respond if you ask them the question about a Caterpillar engine.

Perhaps you could send an email or call the toll free number at Cummins and ask how they feel about using that practice on a Cummins engine.

Personally, I am confident it is a harmful practice to use over a long period of time and I believe it will cause deposits that might result in injector tip fouling and carbon build up but I have no proof or background with engine design, repair, or remanufacture to rely on in making such a statement.

 

[PToombs]

IMO running the engine that short of time is very harmful. The engine doesn't even get warm enough to burn the fuel completely, therefore, you're washing down the cylinders on a daily basis.