| Author | Message | ||
| Ron Frazier
Rating: N/A |
8V71 smokes when cold clears up when warm. New injectors were installed because I wanted to go to 65's and I thought that may be the problem. Smoke seems to be mostly white but there must be some blue because it is also using about 3 to 4 quarts in a 1000 miles. I'm thinking maybe the blower seals may be bad. Compression is from 400 in a couple of cylinders on up to 450. Detroit says anything 400 and above is really good. Starts god even in cold weather runs great has good oil pressure just smokes bad when cold. Any help appreciated. Thanks, Ron 4104 | ||
| daddytoocool Rating: N/A |
plenty normal. don't worry about it. most mechanical diesel engine will smoke until they reach operating temp 180-190. take it from an ol trucker. cat cummins detroit , i have run them all. just make sure after you start the engine you warm it up completely before shutting down. | ||
| Glenn MC-9 Rating: N/A |
"Smoke seems to be mostly white but there must be some blue because it is also using about 3 to 4 quarts in a 1000 miles." My dad was a trucker and heavy equiptment owner for years. His theory was "if it's smokin', everything is getting lubed". We (our singing group) are running a 6V92 in a MC-9, and it smokes the same way until she warms up. I'd "let her rip 'tater chip". Glenn | ||
| Frank Allen Rating: N/A |
I think smoke when cold is pretty normal, when i first got my 06 it smoked terrible when cold and would not clear up till i drove it, but after a few trips that condition fixed itself, it had been sitting a long time. I think it was gummed up somewhat. id run it, Frank allen | ||
| Geoff (Geoff)
Rating: N/A |
Compression for a non-turbo, 71 "N" series is 500 psi minimum. I would be surprised that with 400-450 lbs compression the engine even starts without ether. White smoke is raw unburned diesel, as the engine warms up the compression goes up so the white smoke decreases. It sounds to me like it is time for an overhaul-- leaking blower seals only add oil to the airbox, they do not affect compression. A gallon of oil every 1,000 miles is a lot! Now on Glenn's 6V92, the cold start white smoke may be caused by "smog" timed cams and injectors, and not be a problem. However, most 8V71's do not have this smog equipment smoke. --Geoff '82 RTS CA | ||
| Bill Gerrie
Rating: N/A |
Ron Did you put in N65's without advancing the timing? N60's is the biggest without changing the timing setup. Major work. Too much fuel going in and especially if the compression is low as Geoff states. Time for at least new rings, valves and bearings. Bill | ||
| mel 4104 Rating: N/A |
Ron do yourself and the engine a favour, put a block heater in it and that way you will never have to use eather again just let it warm up by being plugged in for a couple hours and it will start much quicked and depending no how long you let it warm up all the smoke may not show on start up. this way you will not have to use eather to start it will kills the life of the engine Big time. we use block heaters in all of our equipmentand will lnot hire anyone that uses the stuff howere if some one uses starting fliud on any of the eq. the next thing they get is their final pay check as they are fired on the spot, no if and or buts. | ||
| neomax Rating: N/A |
I would not be so hasty to think overhaul. It's not rare that DD MUI engines blow white or grey smoke on cold start-up and most of it can be laid to injectors and timing, not a wore out engine or anything else. 1 gal./1000mi. is a lot but what abt. leaks? My MUI 6v92 w/90's "fogs the valley" on below freezing starts (no ether). At 50 degrees or above, not a trace of smoke. My DDEC 8v never smokes, period. The little 3 cyl. Isuzu on my gen set blows white/grey on freezing starts; a minute later u can breath the exhaust. A friend of mine bought an A3 last year knowing it smoked "bad", figuring a re-build was in order (DDEC 8v). When we picked it up in LA, it killed every mosquito from San Diego to Bakersfield. An hour later over the grapevine @ 70mph, no smoke. He just finished a 7500 mi. trip on 2 gal. of oil. Only time it smoked was a 25 degree start-up in Flagstaff and that was short-lived. You may well have some "excessive wear" or timing adjustment needs, but I personally think it becomes a matter of economy. Just how many miles do u plan on putting on this bus in the next few yrs. and is it worth the expense of a rebuild. Everything was not perfect when the bus was built and I doubt that any amount of money is going to make it that way now, not to mention the time and labor. If u have good oil pressure, it starts fairly quick on cold startup, and no outrageous noises out of the engine engine, I would suggest "over-looking" white/grey smoke on cold starts. Put your efforts into any major oil leaks u may have. | ||
| Johnny Rating: N/A |
The 6V71 (2 valve, N50's) blows a black puff on a cold start, gray-smokes at heavy throttle until coolant temp gets over 130-140 unless it's over ~75 degrees outside. According to the DD guy, the engine is in very good condition (compression 400-450) for a hi-miler (>850,000, mostly city). Ours has used about a gallon of oil every 1000-1200 miles since we got it about a year ago. | ||
| RJ Long (Rjlong)
Rating: N/A |
Ron - Sounds normal to me, including the oil consumption on an older engine. Put a block heater in it, as has been suggested. Plug it in the night before, and in the morning, she'll fire right up nice and clean. Also, if you're going to start it, then DRIVE it! Don't let it just idle to warm up, or to circulate the fluids, then shut it back down. The engine doesn't heat up unless it's under load, which you can only do by driving the thing. 25-50 miles is a good goal, 100's even better. HTH, RJ PD4106-2784 Fresno CA | ||
| Buswarrior (Buswarrior)
Rating: N/A |
Hello Ron. How much do you drive the bus? I find that mine runs a lot cleaner when I'm away on a trip, driving it daily. If it sits, and I do little drives, it seems to smoke a bit more. Also, using the proper oil makes a big difference. I found the oil consumption in mine pretty much vanished when I changed out to 40 weight oil, after running whatever fresh fill came with the bus, which needed topping up at the same rate you are experiencing. Up here in Canada, the commercial side were prone to running 20 or 30 weight in the winter, in an effort to get them to start at the ski hill in the morning at minus 30. (Remember the red gel ether bombs?) Also, money came easier to the bus side than the truck side, they got away with wrecking motors short of their intended mileages. If you run 40 weight in the cold, you have to do some decent pre-heating, or you'll never get the motor to spin fast enough for a start. The 40 weight oil is pretty thick in below freezing/sub-zero, and slows the cranking speed significantly. RJ and Mel have it right. Block heater all night is easy to do for a morning start. Block heater takes a few hours to get a cold engine warm in sub zero. A big Webasto is a substitute for a block heater. At minus 30, 20 minutes of 100 000 BTU Webasto and it starts right up, no smoke. And you get the beginnings of heat from the defroster right away! Up here in the frozen north, sometimes we have no choice in the ether department. The proper use of ether involves spraying a little sniff, maybe a quarter to a half second of spray, down the intake, while cranking. And as noted by Mel, misuse of ether ranks right up there with treason and murder, in a good fleet. Blue flames out the exhaust pipe definitely indicate an overuse... happy coaching! buswarrior | ||
| R.C.Bishop
Rating: N/A |
I have Ether, block heater and Webasto. Use Ether regularly if I don't know, in advance, that I want to use the coach. Push the starter, give a few cranks, if it doesn't start just a quick, VERY quick shot of Ether and off she goes.....smoke and all. Lasts only a short time, then clears up. Not necessarily recommending this, but the coach came from Flagstaff, AZ; it lived there 37 years and survived those winters with Ether, so presume it must be a viable solution to a difficult decision process.  FWIW RCB 64 Crown Supercoach (hwc) | ||
| Rob Leight (Robleight)
Rating: N/A |
Mine does that when the outdoor temp is below 45 degrees. I put a block heater on it, and now it starts with no smoke. |