| Author |
Message |
R.C.Bishop (128.123.88.22)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 23, 2001 - 9:36 pm: | |
For the Diesel Mechanics out there. When I bought this bus in June I was forewarned that the engine, Cummins 225 turbo, 58,000 since major, ALWAYS emits white smoke when first started and on most occassions going up a steep grade.
After it has run for a while, air pressure to 120, engine warm, etc, it generally clears and things are diesel normal...as I understand them.
Comments? Thanx, in advance.
RCB |
Rich (24.147.234.166)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 24, 2001 - 1:51 pm: | |
White smoke is generally an indication of antifreeze being burned. Might want to know if it is losing antifreeze or not. |
jim (209.240.222.32)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 24, 2001 - 9:20 pm: | |
white smoke is also a sign of lower compression/poor performance.....if you were "burning" antifreeze, you would be able to smell it..... if the fumes burn your eyes, it may be running really rich (overfueling)...an engine thats smokes white/grey then clears up suggests that there is wear evident in the clyinders..... and after the engine heats up, it runs better....i'd sugest setting the intake/exhaust valves, adjusting the injectors, and doing an oil analysis....this basic type tune-up should help in further diagnosing a problem.... |
R.C.Bishop (128.123.88.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 24, 2001 - 9:41 pm: | |
HEY Jim,..Thanx and Rich also. Antifreeze seems OK. Would say the scenario outlined by Jim pretty well says it. Doubtful welcome at an overnight place, huh? There's a definite smell, but not like antifreeze...exhaust mainly. |
Tom Caffrey (Pvcces) (12.146.32.209)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 25, 2001 - 9:17 pm: | |
RCB, the fact that you have a turbo diesel means that you can expect to have a little lower compression ratio and more white smoke on startup.
Since the fuel is burned entirely by the heat of compression, a cool engine will not burn its fuel completely, hence the white smoke.
This does nothing to explain the presence of white smoke while pulling a grade, and would lead me to investigate its causes. You should not see white smoke when the engine is working hard, AFAIK.
If a diesel fires the fuel in a cylinder, but there is much more fuel or much less air in the chamber than it needs, that cylinder will produce black smoke.
The white smoke that occurs during warmup is due to some cylinders injecting when their chambers are colder than others, the warmest ones burning the cleanest, and any that misfire producing a fairly heavy white smoke.
The best way to minimize white smoke in such an engine is to put a slight load on it while it warms up, such as putting an automatic in gear.
The slowest idle that you can comfortably tolerate will also help build chamber heat. Fast idling can lead to misfiring.
Hope this helps.
Tom Caffrey PD4106-2576 |
RC Bishop (128.123.88.25)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 25, 2001 - 10:25 pm: | |
Thanx, Tom...it does help. I have only "driven" the bus one time for any length. Many, many grades between Flagstaff, where I bought it, and Las Cruces, where I live. Did not see any white smoke, and for that matter not much smoke at all, though I knew when I got it home that I had driven a diesel.
The back side was coated... I had driven several hundred miles (10 hours of driving) in 7th to 10th gear for the most part, 65mph and 1700, or so RPM. I could be mistaken on the RPMs, but not much lower than 1500, I'm sure. Ran great and got about 11 mpg. Used less than a half a hundred gallon tank. Down shifting on the grades didn't show a bunch of smoke as I recall. Oil Consumption was nil and ran smooth all the way.
Upon start up several days ago, it about smoked me out. Hadn't started it in a while, so thought that might have something to do with it. Next startup I'll try a lower idle till it warms.
Really 'preciate the info, Tom. Muchas Gracias!
RCB |
Henry Draper (12.82.141.229)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 25, 2001 - 11:10 pm: | |
My input is pretty much the same as Tom's--I have a 8V92TA in my Eagle. I was worried about white smoke at startup, but have been convinced by several knowledgable folks, not the least of which is Mike Melchore (or something like that), the Detriot Diesel rep that gives seminars at Bus Conversions conventions and FMCA conventions, that white smoke in a big, turbocharged engine at startup is nothing out of the ordinary.
I'm writing, however to tell you what I've done to minimize aggravating the neighbors at campgrounds. I just plug in my block heater for a couple of hours before I start the engine--no smoke!
Actually I've rigged a relay inside the bus so all I have to do is flip the switch and the block heater starts doin' its thing. No embarrasment when I fire it up a couple of hours later!!
Preheating the engine is a pretty good thing to do for it anyway.
Henry Draper
'64 Eagle
Edmonds, WA |
R.C.Bishop (128.123.88.17)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 25, 2001 - 11:35 pm: | |
Thanx, Henry.....I've got one. Needs to be re- wired as you suggest. Great Idea......RCB |
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