how bad is black smoke?
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From: College Station, Texas
how bad is black smoke?
i was talking to a CAT mechanic yesterday and he was telling me that black smoke is horrible for the engine. He said that the un-burned fuel is washing down the cylinder walls. He said thats horrible for the cylinders and will drastically shorten engine life.
Now i know of tons of high mileage black smoking diesels...so is there any truth to this? I would guess that there is some truth to it just not as bad as he is making it out to be. (ofcourse this conversation was after he followed me onto an onramp where i had to get on it in Crazy Larry)
either way, my truck will keep smokin! my truck could smoke stock so i can't see it being as much of an issue as he made it out to be.
The whole theory of the unburned fuel washing down cylinder walls makes me ponder...when my truck was stock, if i didn't get on it for 1000 miles and then layed into it, it would smoke like freight train....so is that unburned fuel building up? and if it built up like that, it must be good to clean it out????
Now i know of tons of high mileage black smoking diesels...so is there any truth to this? I would guess that there is some truth to it just not as bad as he is making it out to be. (ofcourse this conversation was after he followed me onto an onramp where i had to get on it in Crazy Larry)
either way, my truck will keep smokin! my truck could smoke stock so i can't see it being as much of an issue as he made it out to be.
The whole theory of the unburned fuel washing down cylinder walls makes me ponder...when my truck was stock, if i didn't get on it for 1000 miles and then layed into it, it would smoke like freight train....so is that unburned fuel building up? and if it built up like that, it must be good to clean it out????
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From: New Holland, PA
Black smoke is mostly carbon (aka soot). An overfueled engine will put more soot in the oil, which can lead to excess wear if the oil changes aren't kept up with. Unless you are so overfueled that you have white smoke with no load, you are not getting fuel washdown.
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Joined: Nov 2004
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From: Northern Virginia
A good solution for the heavy smokers is a oil by-pass filter system like Oil Guard, Amsoil, etc... They will filter out all the engine wearing soot particles. I installed the Oil Guard about a month ago and it seems to work like a champ. Installation was a snap and seems to be engineered very well.
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From: Near Mt. Pleasant, Tennessee
When I picked up my truck from the body shop after 3 weeks my boy(6) was watching his mirror...he missed the Cummins. We took off in second and it had a pretty good size black cloud as we got into her a little to get up to speed, and it did it everytime I shifted. I started to wonder if they slipped a box on my truck for free just because it took so long. It was neat to watch out the mirror! 
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From: texas
Black smoke is fuel that was at and above combustion temperature, but the flame went out for lack of oxygen - it is therefore much denser than the completely burned waste gasses which are a byproduct of combustion.
Minimum temperature of combustion is 1625 degrees F.
Waste combustion product is gaseous, very low density with little mass, unable to retain that temperature as it exits thru the exhaust path - the temperature of that exaust gas begins dropping rapidly as it exits the cylinder.
However, the denser unburned fuel leaves the cylinder at temperatures just below combustion - the denser mass allows it to retain the high temps, and anything in the exhaust path will then be subjected to those elevated temperatures.
Result - high EGT's.
Also result - poor fuel economy.
That is the major problem with black smoke - that, and the smog cops
Minimum temperature of combustion is 1625 degrees F.
Waste combustion product is gaseous, very low density with little mass, unable to retain that temperature as it exits thru the exhaust path - the temperature of that exaust gas begins dropping rapidly as it exits the cylinder.
However, the denser unburned fuel leaves the cylinder at temperatures just below combustion - the denser mass allows it to retain the high temps, and anything in the exhaust path will then be subjected to those elevated temperatures.
Result - high EGT's.
Also result - poor fuel economy.
That is the major problem with black smoke - that, and the smog cops
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From: Garrard county, Kentucky
I dont think smoke is anything to worry about. I wouldnt go around lugging a heavily fueled truck all the time making it pour the smoke, but it shouldnt hurt anything other than that. I can lug mine if I want, but I usually try to drive without a lot of smoke. And suit gets built up in the exhaust if you put around a lot. Then when you finally get on it, it will blow all that suit out, and smoke like crazy(dads does)
Eric
Eric
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From: College Station, Texas
i always watch the EGT's.....and thats what i thought my only real concern should be. I guess it is....
I rarely lug it for a smoke show.
Ok thanks guys i am more educated to argue the next time i see this CAT mechanic friend of mine.
I rarely lug it for a smoke show.
Ok thanks guys i am more educated to argue the next time i see this CAT mechanic friend of mine.
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From: texas
Cat and Cummins and other Diesel engine oem have done some studies which indicate that long periods of idling results in heavy fuel condensation on the cylinder walls, causing excessive upper cylinder ring-to-wall wear - could be the high fuel-to-air ratios which result in intense black smoke cause similar wear.
