| Author | Message | ||
| dutch (Dutch)
Registered Member Username: Dutch Post Number: 89 Registered: 2-2007 Posted From: 216.9.250.6 Rating: N/A |
He folks Can anybody tell me the difference between black blue and white smoke??? Also when you see it at startup or after like 300miles Thanks dutch | ||
| Jerome Dusenberry (Jerry32)
Registered Member Username: Jerry32 Post Number: 24 Registered: 1-2007 Posted From: 148.78.243.51 Rating: N/A |
Normally when you start up you may see white smoke if the engine is cold, It is unburnt fuel. Blue smoke is usually represenative of crankcase oil and black smoke is not enough air for the fuel to burn completely or put another way too much fuel for the air that the engine is getting. this is when heavy throttle or bad turbo etc. Jerry | ||
| doug yes (Dougg)
Registered Member Username: Dougg Post Number: 28 Registered: 1-2007 Posted From: 75.117.52.139 Rating: |
They all indicate that the engine is running on a 4104! | ||
| Kyle Brandt (Kyle4501)
Registered Member Username: Kyle4501 Post Number: 335 Registered: 9-2004 Posted From: 72.147.49.137 Rating: N/A |
Blue = burned oil Black = UN-burned fuel White smoke is usually water. Small amount of white on startup is condensation of combustion by-products. Usually goes away as soon as exhaust system heats up. Tons of white smoke that doesn't go away is usually a coolant leak which will require intervention & $$$ Burned automatic transmission fluid (in my car) looks white in the rear view mirror, but was intermitent. (Replacing the vacuum modulator fixed that.) | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1103 Registered: 5-2001 Posted From: 206.116.245.127 Rating: N/A |
Kyle, white smoke is just as likely to be fuel that did not ignite as it is to be water. Try getting a whiff of it in your face. The difference is very obvious. The unburned fuel will burn eyes and nose. Blue smoke from lube oil burning shows up readily, even when the oil consumption is normal or near normal. Cold firing chambers can even produce some blue from the fuel; the chambers have to be hot to produce clean exhaust. If an engine blue smokes when working hard and fully heated up, then oil consumption is apt to be high. The is the exact priciple behind municipal incinerators; temperatures have to exceed 1800 degrees F to be clean enough to use the incinerator. Wood stoves are the same way; if they don't burn hot enough, they will be smokey even with good fuel. White smoke from fuel is not a combustion product; it is from failure to ignite. A lot of the two strokes are a little marginal on compression, so a misfire or two on startup is common. As the cylinder warms up from repeated compression strokes, it finally gets hot enough to fire. If you see a lot of smoke on startup, there will be more than one misfiring. If you watch, you will see the smoke reduce in stages as each nonfiring cylinder starts firing. Right when that happens, there is some intermittent firing, and you can see it in the exhaust. If you are running an engine that is all the way up to temperature and it white smokes, then it is likely that water is involved. Black smoke means that the fuel was hot enough to ignite, but ran out of air partway through the burning of the fuel. I hope this helps clear the air. Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 150 Registered: 7-2006 Posted From: 63.18.122.108 Rating: N/A |
Good post TC.....Thanx. RCB | ||
| Phil Dumpster (Phil_dumpster)
Registered Member Username: Phil_dumpster Post Number: 18 Registered: 5-2005 Posted From: 71.112.107.234 Rating: N/A |
Umm, water makes steam, not white smoke, when heated beyond its boiling point. How do you tell the difference? Unless the local humidity is above 99%, steam will "vanish" into thin air, while smoke will dissipate until no longer visible. I have a 6V92TA with about 40K miles on it. At 50 degree ambient temperature, normal starting sequence is like this: start cranking, at 4 to 5 seconds the first wisps of white smoke come from the exhaust, over the next 2 to 5 seconds they get thicker until the first pings of ignition come from the engine, when the smoke turns thick and black. Until all six cylinders start firing, which can take anywhere from 5 to 10 seconds at idle, some black and white smoke chuffs out in rhythm with the engine speed. When all cylinders are firing, it stops smoking. If your engine is in good shape, it should act much like mine does. My engine has a transit bus throttle retarder, so it doesn't shoot anything visible out of the exhaust stack even if I floor it. If your engine doesn't have one, you should be able to shoot mushroom clouds on demand with your right foot. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 580 Registered: 10-2003 Posted From: 71.58.117.21 Rating: N/A |
Plug in the block heater and see how it acts. Should start clean if it is in good shape. Blue or white smoke then indicates a problem. Nice thing about detroits is they run the best when they are ready for an overhaul, along as they aren't misfiring. | ||
| Tom Caffrey (Pvcces)
Registered Member Username: Pvcces Post Number: 1104 Registered: 5-2001 Posted From: 206.116.245.127 Rating: N/A |
Phil, I think that whether you can see water vapor depends on conditions. I believe if the water vapor temperature falls below the dew point for the conditions, the vapor will become visible. HTH Tom Caffrey PD4106-2576 Suncatcher Ketchikan, Alaska | ||
| Kyle Brandt (Kyle4501)
Registered Member Username: Kyle4501 Post Number: 336 Registered: 9-2004 Posted From: 72.147.49.137 Rating: N/A |
Good points Tom, but my 8V71 starts with a little white smoke & smooth even firing. I try to avoid putting my head in smoke  The cars I have seen with blown head gaskets would put out a cloud of steam that would make Q (007) proud. It too would bring tears to your eyes, I just assumed it was other by-products of combustion. Oh, the comment I made about "Tons of white smoke that doesn't go away" I was refering to continuous generation of smoke, not how long it lingered in the air. I learn more every day - If I'm lucky | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 371 Registered: 11-2005 Posted From: 63.97.117.35 Rating: N/A |
Phil, That doesn't sound like normal DD starting to me. My 671 will make some white smoke at 30-40 degrees but even then it isn't as bad as yours. Ether eliminates white smoke completely even at 20*. | ||
| Phil Dumpster (Phil_dumpster)
Registered Member Username: Phil_dumpster Post Number: 22 Registered: 5-2005 Posted From: 134.39.82.45 Rating: N/A |
Normally aspirated engines will start easier and with less smoke that the equivalent turbocharged engines because the normally aspirated engines have a higher compression ratio. Once the turbo engine is warmed up to operating temperature, it will outperform its normally aspirated counterpart in almost every measurable sense. |
