Blue smoke on start up: 6BTA

[dhays]

A bit of thread drift but....

My marina is at the head of my little harbor. It takes 20 at least from start up to get out of the harbor which is all a no wake zone. That means at least 20 minutes of idling, more if I am stopping at the pump out on the way out, which means another almost cold start.

Other than a oil pan heater (on my list), is there anything that can be done to minimize any negative affects? I have not checked how long it takes to get up to temp while leaving the harbor.

 

[Tony Athens]

Once you are in gear, that is way better than at the dock in neutral. Plus, you are going on a "trip"..

 

[creekcrab]

Thanks Tony Athens for the great info. I will turn on the block heaters on 3208's today and will no longer crank the engines and let them idle at the dock to "exercise them".

 

[Tony Athens]

What exact kind of block heaters do you have?

Tony

 

[creekcrab]

What exact kind of block heaters do you have?



Tony

Not sure. I will have to check. They are the original installation on a 45 Californian

 

[Tony Athens]

If these are high wattage coolant immersion heaters, then I would be very cautious about leaving them plugged in all the time regardless of a thermostat or timer, and especially so if "original from decades ago".. I went that route up to about 10-12 yrs ago and after seeing so many issues with them in the "Boat Environment", I went the other direction. Very low wattage run all the time.

 

[Lou_tribal]

Lou, you are missing what I am saying.. I did not say anything about idling your diesel once it gets up to operating temp after RUNNING under loaded conditions ( LIKE GOING ON A TRIP)..

What I am saying is to not run it at an idle ( or even above an idle) when it is not up to full operating temp or trying to warm it up under no load at the dock.. Once the engine is hot from a trip, you can idle all day if you want--but the coolant temp needs to be above 175-ish... As I said, you are causing your own issue with your "protocol" of operation... As to comparing it to Trucks & Locomotives--not even close to apples to apples-- One, they do not have saltwater cooled aftercoolers sending 80F or less air to the combustion chambers, two, they are not 60HP/liter diesels( more like 50% or less than that) , and three, I really doubt they warm they up from DEAD COLD at an idle, and for certain they are not trying to warm them up only to shut them down..



Tony

Tony, you are missing my question
I understood what you said especially about starting the engine to shut it down few minutes later and I agree totally with it.
My question was only geared toward unerstanding why running the engine at idle at the dock is not good, in other terms what are the effect of doing this, and what are the causes of these effects, and what is different when being underway. Not sure if I m clear or not but don't know how to phrase it differently.

Regarding my own protocol, don't know why you wrote this, I never wrote anything about it ??? My own protocol is pretty much the same you described, start engine, do a quick check that everything is fine, and go gently while warming up underway.

I am not asking espcially this for big high power modern engine, mine is far below your 60hp/L (more like 10hp/L lol), just that I am interested in understanding what happens.

Thank you anyway to have taken time to answer me.

L.

 

[DavidM]

Lou:

It is a matter of time spent warming up. A marine diesel in neutral at idle will warm up very slowly and may never reach operating temperatures. My engine won't. But if I motor slowly at 1,000 rpm (less than 5 kts) it will get to operating temperatures in ten minutes or so.

i motor at 1,000 rpm to clear the docks, then 1,200 rpm (about 6 kts) to get to open water. Then when the temp gauge shows about 150 F I open it up to slow cruising speed- 1,600 rpm and I never go to high speed unless the temps have stabilized at 180 F.

The longer it takes to warm up the more unburned fuel gets into the crankcase and the more fuel, oil and soot collects in the exhaust manifold and piping. When it finally gets up to operating temps, this fuel, oil and soot production is diminished greatly.

So warm up fast under even a small load, then it is ok (but not preferrable) to idle after it is warm.

FWIW, California and maybe other state and federal jurisdictions prohibit long idling of cars, trucks and even construction machinery, more for pollution consideration than engine health. Theoretically you can get a ticket if you leave your truck idling too long.

David

 

[Lou_tribal]

Lou:

It is a matter of time spent warming up. A marine diesel in neutral at idle will warm up very slowly and may never reach operating temperatures. My engine won't. But if I motor slowly at 1,000 rpm (less than 5 kts) it will get to operating temperatures in ten minutes or so.

i motor at 1,000 rpm to clear the docks, then 1,200 rpm (about 6 kts) to get to open water. Then when the temp gauge shows about 150 F I open it up to slow cruising speed- 1,600 rpm and I never go to high speed unless the temps have stabilized at 180 F.

The longer it takes to warm up the more unburned fuel gets into the crankcase and the more fuel, oil and soot collects in the exhaust manifold and piping. When it finally gets up to operating temps, this fuel, oil and soot production is diminished greatly.

So warm up fast under even a small load, then it is ok (but not preferrable) to idle after it is warm.

FWIW, California and maybe other state and federal jurisdictions prohibit long idling of cars, trucks and even construction machinery, more for pollution consideration than engine health. Theoretically you can get a ticket if you leave your truck idling too long.

David

David, thank you very much!
This is the explanation I was looking for

So if I understand correctly it is because warming up slowly result in badly burnt fuel that accumulate in the engine.
I read in a diesel mechanic book that cylinders have very tiny kindof "stripes" inside and idling the engine while cold tend to "wipe" these "stripe" and damage the cylinder. Is that true?

Sorry for the wording I do not remember the exact terms in English I will ned to re read this book to find the correct wording.

L.

 

[Tony Athens]

My screw up--I got you and "William R" mixed up..
Too many things.. Sorry

 

[Xsbank]

As I understand it, engine cylinders typically have "hone marks" in them that are quite small but hold oil and provide a better surface for piston rings (they circle the piston and contact the cylinder walls to contain the combustion pressures as well as wiping the cylinder walls clean AND uniformly coating the cylinders with oil for lubrication) to ride upon. If you overheat or don't warm properly, for example, these hone marks get worn off and the cylinder is said to be "glazed." A glazed cylinder will not contain the combustion process properly ("blow by") and the cylinder can be damaged to a point where it starts to eat the piston and metal begins to transfer to the cylinder walls. At this point it might even seize up, break a rod or piston and even put a hole in the block, essentially ruining the engine.

This is the famous problem with the number 6 cylinder in some Lehman engines, that you can read about on here or the GB site.

I personally think that warming up at the dock and shutting down contributes to the demise of the engine before it's time for all the previous reasons as well as the cool engine is not burning all its fuel so some of it washes the oil off the cylinder walls as it finds its way into the crankcase, such that the next time you start there is no oil on the cylinder walls initially and significant damage is done to the cylinder bores and rings.

Diesel engines generally will not warm up properly without a load as they are fairly efficient, they transform more of their fuel to work and less to heat. A gasoline engine is less efficient and has lots of excess heat to get rid of, some of it is useful for heating the cabin, etc. My old 2004 Golf diesel would never even get the temperature gauge off the low stop if it was below freezing and you tried to idle it warm. Even stopped at a light you could watch the gauge fall as you waited for the light to turn. Those older cars had "glow plugs" (VW term, not what we know as glow plugs) in the coolant jacket to heat the water electrically on cold days. This gave you a small amount of cabin warmth but it's real purpose was to try and warm the block for lower emissions. We all know the solution to pollution (!) that VW came up with...

 

[Lou_tribal]

My screw up--I got you and "William R" mixed up..
Too many things.. Sorry

No worry Tony

 

[Lou_tribal]

As I understand it, engine cylinders typically have "hone marks" in them that are quite small but hold oil and provide a better surface for piston rings (they circle the piston and contact the cylinder walls to contain the combustion pressures as well as wiping the cylinder walls clean AND uniformly coating the cylinders with oil for lubrication) to ride upon. If you overheat or don't warm properly, for example, these hone marks get worn off and the cylinder is said to be "glazed." A glazed cylinder will not contain the combustion process properly ("blow by") and the cylinder can be damaged to a point where it starts to eat the piston and metal begins to transfer to the cylinder walls. At this point it might even seize up, break a rod or piston and even put a hole in the block, essentially ruining the engine.

This is the famous problem with the number 6 cylinder in some Lehman engines, that you can read about on here or the GB site.

I personally think that warming up at the dock and shutting down contributes to the demise of the engine before it's time for all the previous reasons as well as the cool engine is not burning all its fuel so some of it washes the oil off the cylinder walls as it finds its way into the crankcase, such that the next time you start there is no oil on the cylinder walls initially and significant damage is done to the cylinder bores and rings.

Diesel engines generally will not warm up properly without a load as they are fairly efficient, they transform more of their fuel to work and less to heat. A gasoline engine is less efficient and has lots of excess heat to get rid of, some of it is useful for heating the cabin, etc. My old 2004 Golf diesel would never even get the temperature gauge off the low stop if it was below freezing and you tried to idle it warm. Even stopped at a light you could watch the gauge fall as you waited for the light to turn. Those older cars had "glow plugs" (VW term, not what we know as glow plugs) in the coolant jacket to heat the water electrically on cold days. This gave you a small amount of cabin warmth but it's real purpose was to try and warm the block for lower emissions. We all know the solution to pollution (!) that VW came up with...

Hone marks that was the term I was looking for!
Is cylinder washing occurs with diesel? I knew that on gasoline engine as gasoline dissolve oil but diesel fuel is a kind of oil isn't it? Is it able to wash oil on cylinder wall?

Sorry if I hijack the thread a bit, I think it still on the same overall subject but don't want to bother OP

 

[C lectric]

Cylinder washing from unburned fuel -----YES

Unburned fuel can wash oil off the cylinder walls and ends up in the crankcase which will dilute the oil. If enough accumulates it can cause trouble by excessively thinning the oil.

It cannot be 100% avoided but if the engine is "run" on a "trip" for long enough to fully heat it up that problem will be held in check and the diesel in the oil will be cooked off.

 

[Tony Athens]

Add this much overlooked point-------------oil temps really need to get above 200F as soon as possible to free the oil of excess moisture.. If running slow for hours on end, it's always best to get the engine up to a high cruise HP load so the oil temp rises for a few minutes at the very least. One can assume that oil temp typically runs 15-50F higher that coolant temps after all has been hot for a couple of hours.. This is GOOD THING..Oil temps never get close to hot "trying to warm up at the dock".

Tony

 

[dhays]

Once you are in gear, that is way better than at the dock in neutral. Plus, you are going on a "trip"..

Thanks Tony.

I was down at the boat today and one of the things on my list was to check out the oil pan with the idea of adding an oil pan heater (something I have been thinking about since I bought the boat less than a year ago).

I discovered that the bottom of the oil pan has groves running for and aft in the shallow section of the pan and of course a drain and oil line at the bottom of the deep portion for my oil change system. Thus left me in a quandary as how I would glue a pan heater on the bottom.

It is a Cumins 5.9L QSB 380 engine circa 2009. Any ideas?

 

[johnrupp]

Tony
A little thread drift since the OP's question was answered. Is it beneficial to use pan heaters on a boat during in water winter storage? Say three months without starting engines.

 

[Lou_tribal]

Add this much overlooked point-------------oil temps really need to get above 200F as soon a possible to free the oil of excess moisture.. If running slow for hours on end, it's always best to get the engine up to a high cruise HP load so the oil temp rise for a few minutes at the very least. One can assume that oil temp typically runs 15-30F higher that coolant temps after all has been hot for a couple of hours.. This is GOOD THING..Oil temps never get close to hot "trying to warm up at the dock".

Tony

Talking of oil temp... Once I talk to a mechanic who told me that we always look at water temp for engines gauge but what is most important is oil temp as if you look at water temp, when reaching unusual high value, oil temp reached far higher value so monitoring oil temp gives you a ahead warnig than water temp. What do you think about this? He was not talking for boats with oil cooler so this may not apply but I would be curious aboyt expert advice

 

[Tony Athens]

Never seen such an oil pan on any QB 5.9 Marine engine. Send me a good pic and an engine serial.

Tony

 

[C lectric]

Lots of boat engines have the oil cooler cooled by coolant. So the oil will always be hotter than the coolant oncew all is warmed up as stated . Mine is that way which in many ways is good as the oil will be heated faster when cold and kept well warmed once coolant is up to temp.

A few, usually high HP engines or raw water cooled engines , have seawater cooled oil coolers and those will be dead cold until the engine is under a good load. Cold oil does not flow well so does not lube well either.

Years ago I tried to heat my engine for an oil change. Ran it for 40 or so minutes tied to the dock in gear. Shut 'er down and tried. NO DICE> the oil was stone cold. Coolant was heating but the oil was no where near even warm. Never again. Oil change, for me, includes a run for ~ 1 hr. Then the oil is hot, easily pumped and contains much of the contaminants you don't want left. Just need to take care as hot oil can burn skin.

 

[dhays]

Never seen such an oil pan on any QB 5.9 Marine engine. Send me a good pic and an engine serial.



Tony

I will do that. Thanks.

I will have to get a photo but the serial number is #46951316

 

[creekcrab]

If these are high wattage coolant immersion heaters, then I would be very cautious about leaving them plugged in all the time regardless of a thermostat or timer, and especially so if "original from decades ago".. I went that route up to about 10-12 yrs ago and after seeing so many issues with them in the "Boat Environment", I went the other direction. Very low wattage run all the time.

They are definitely coolant heaters. Mine are 120v so if the chart is correct they are 500w heaters. We love in the south (SC) so we don't have many cold nights. I am guessing i should turn the block heaters on for the cold nights and a few hours before cranking.

 

[dhays]

We love in the south (SC) so we don't have many cold nights.

That is one fun way way to keep the nights warm.