We have a 6v71 in our West Coast yarder and it blows an extreme amount of black smoke. We put a new air filter on it and it still has not alleviated the problem. Do these usually have injector issues where they could be over fueling? It is so bad that it has covered our processor in soot within 200 hours of running.
Need more info , under load , picking up load ect. just started done all along ? Check air filter intake. could be injectors. Bob
Somebody correct me if I am wrong but I think in truck engines the horsepower/fuel volume was set by injector part number. Larger injectors=more fuel possible. So maybe some clown along the way decided to "increase power" by putting in oversize injectors. Check the part number, should be pretty easy to figure this one yes or no.
It is under load. Only one when yarding a turn in does it do it.
Not sure where it sets on a V6-71 but if the return line restrictor is wrong sized for the injectors or partially plugged it could contribute to black smoke. On a inline engine they are the 90 degree brass fitting coming out of the head on the return fuel line. Is this condition new in the last 200 hrs you ran it or is this a newly acquired machine that came with the black smoke problem?
Started with the questions/suggestions below and almost forgot the most important questions! Is this something new or has it done it for as long as you have been around it. Next important question is other than the new air filter has anyone done any work on this engine? To me these are the most important things to know before trying to diagnosis a problem! Now back to the other questions in no particular order just as they come to mind: You say it's Non-Turbo so one idea would be to remove exhaust manifolds and run it to see if the smoke is coming out of all exhausts the same black snootiness. Just be sure to wear hearing protection! Also check for restriction in the exhaust side of things, if exhaust can't get out fresh air for combustion can't get in! Have you checked to see if there is anything covering the screen on top of the blower? Did someone stick a rag in intake while changing air filter and forget to remove it? Can you take the top off the blower and see that the emergency shut down is fully open when latched? Do the rotors of the blower look nice and clean or are they coated with black greasy gunk? Other have made good suggestions and I'm sure more will have ideas as well. May even help if you could post a short video or even a picture to let us see more or less first hand what the exhaust actually looks like. A little puff of smoke when first getting into it might be normal but if it looks like an old steam engine pulling a grade not so normal!
It is like an old coal train when it is pulling a turn. It is done this ever since we got the machine and we have a couple hundred hours on it now. Thanks for the tip on checking the blower as I had forgot about the emergency shutdown on there.
Another thing to check is for loose air box covers or blown out cover gaskets. seen that a time or 2. Another thought is what's the oil consumption? I have seen leaking piston pin retainers make black smoke on a hard pull.
That's what gets me, it is not using oil and it is very light on the fuel usage also.
Well don't let it continue because all that soot is basically like dust tearing up the innards of the motor. A puff here and there is OK but not all the time.
Air box cover leaks! That's a good one I forgot about! Loose or leaking airbox cover(s) would effectively be the same as a bad turbo on a turbo engine, low boost so not enough air to burn the fuel that the injectors are pushing out under load. If you have access to a manometer or pressure gauge that reads in inches of mercury you can attach it to one of the airbox drains, those pipes that hang down on the side of the engine and tend to drip oil! Under full load at 2,100 RPM you should have between 5 and 8.2 inches of mercury pressure on those tubes. That is only equal to 2.5 to 4 psi so need a good gauge to read that low accurately. Might not have anything to due with the smoke but what are you using for oil? Detroits like straight weight 40 or 50 SAE oil with the right additives. Somebody can probably point to a long thread here on that subject!
Here are a couple of ideas that sort of have been mentioned. Injectors should be 65 MM or less. The 70 and 75 are for turbo engines providing more air. Faulty blower drive seals could have caused oil slime to plug the blower screen, losing air flow. A faulty tune up. If the valves are not set right, you're not in time; same with injector heights; should be 1.460. Crushed or damaged air cleaner or air cleaner housing.
Have some one do a overhead on the engine. Bob
I'm thinking emergency shut down like khansen mentioned, or blower seals etc. My 6-71 inline with no turbo doesn't black smoke at all, and I'm working the snot out of it dragging around 80,000 of crane. Mine will tend to burn off slobbered oil that wet stacks in the exhaust manifold when I'm doing too much idling on a jobsite with the crane. Usually about 3 miles down the road it gets the exhaust manifold warm enough to burn it out. It doesn't use much oil, but it will smoke that out when it finally gets hot enough. If he's sitting there quite a bit between turns, and then has a hard pull, it may warm it up enough to burn that oil out. If yours is wet stacking you'll see it around the exhaust manifolds and piping.
Yeah I haven't noticed any of the wet stacking or blubbering. It is usually about 2 minutes between turns Max.
How did I miss a Detroit thread? Shame on me. Worst thing is I can’t think of anything to add! That sound you hear is my head banging the table..... Good luck. I’ll fly up and sort it out for ya if you want! Haha
1.460 is no Bueno in a natural aspirated 71 series with advanced cam timing (and most are), 1.484 is the proper timing pin for them. 1.460 in an engine with advanced timing will lead to broken top rings and missing piston parts. Usually the top ring land. Check the rocker cover tag before tuning one of these engines.
Yes but no telling what Billy Bob has been in there and done before you got to it.... Any way to tell how the cam may be timed without pulling the engine apart? Dial indicator and degrees but is that info published anywhere?
There is a procedure in the service manual to check cam timing. Don't remember it off the top of my head, but it does tell you where the cams are set. And yes, I have seen some strange combinations from engine swaps.
It's not necessarily a Billy Bob but definitely a {whoodly dang} that one should worry about tinkering around under valve covers. Truck Shop
It has been awhile but I am fairly positive 1.460 is for regular timing, non turbo. I don't have my manuals anymore, but in the day I have rebuilt 3-400 of them Worked for a DDA distributor so I have changed a lot of engines from standard to A timing along with spending 6 months in the dyno room doing run-ins and tune ups. Depending on which of the eight engine configurations, a lucky guess would be to pull the rear cam cover on the right side and roll the engine (1 1/2 in socket) until you see the cam timing marks line up. With luck you will be able, maybe a mirror on a pole, see the timing mark on the idler gear. An A timed engine is stamped with an A and is one tooth next to the standard timing mark I once spent weeks retiming 60 new Carlo Rossi Winery Freightliners from standard to A timing and installing bigger injectors (12V71).
I preach that every time I see a Detroit thread. 15W/40 will destroy those engines. Use only SAE 40 with a sulfated ash content of 1.0% or less. Rotella SAE 40 won't do. Two good choices are Delo 100 SAE40 (not Delo 400, ash content too high) or Mobile Delvac 1240 SAE 40
I saw some weird stuff our old friend Carl did...
Pop the valve cover off & identify the injectors first . Sounds like the engine is running good & making power ? Engine possibly overloaded for the task ? # 65 injectors will put some smoke out when ya puller down on RPM .
Well if anyone is interested in checking what the cam timing is on a Detroit here's the instructions out of the book to figure it out:
Spot on Ken ! That's exactly where most of our Detroit's run on the boost pressure . 2.5 to 4 PSI . The 71's seem to run close to 4 and for some reason the 53's run lower around 2.5 to 3 . The 8-V 38 builds 7 PSI around 4,000 RPM and I'm afraid to push him much past that . Don't want any " Black smoke " or oil slicks .
About this " Billy Bob " Stereotype ……. Sensitivity training for all you fellers ……. LOL !
A simple test if you are in clean air. Pull the air cleaner off and give it a turn. Maybe some one crunched one in he past and put to small of a air cleaner on it and it is not getting enough air under load.
Great info fellas! I'll be glad if Uncle Gus hasn't gotten his hands on it!
So how does 15w-40 destroy a engine ? curious minds want to know . Bob
Same thoughts Bluox …. My experience is the Detroit Engine will run on any kind of oil as long as it's slick ? If there was a tougher user friendly engine I would sure like someone to point me to it .
I cant explain the whole thing, But it was told to me that 2 stroke Detroits "shear" the molecules in oils. 15/40 just breaks down that much faster and crawls past the oil rings and gets up and creates deposits on the compression ring grooves that stick the rings. I had a customer running 2 twin power Wabco scrapers with 12V71T engines that were burning 1.5 gallons per day per engine. After getting them off 15/40 and switching to 40wt Delo 100, they were burning 2 quarts a day per engine. That was in 90 degree temps. in the colder season it was 30wt.
That right there! It's the viscosity modifiers in multigrade oil (15w/40), two stroke Detroit's don't like that stuff. Use of 15W/40 in those engine will cause increased oil consumption and shortened piston/liner life, it just is what it is, those engines do not like 15W/40. Use only SAE40 with a sulfated ash content of 1.0% or less for best engine life
Detroit put out bulletins that were very clear about the subject, sometime in the 1990s I think.
Yep, echoed by Tejas Coach who worked a fleet of two stroke Detroit engines. > http://www.tejascoach.com/tech.html
The 15W-40 Vs. Straight 40 thing could be similar to the difference between running a good long life coolant to straight water for coolant. Engine will run just fine with the straight water in the cooling system but.......give it time and you will start having problems! Heck you could go down to the local greasy spoon grill and drain some of the oil from the deep fryer and put it in you motor and it would probably run okay for some time but I would not suggest doing that for a truck going cross county on the Interstate hauling an 80,000 load.
I got sent to a school many moons ago where the Detroit people were pretty emphatic about straight grade 40 weight. Use multi-grade and watch your warranty disappear in the smoke going out the stack. They would suspect as soon as you gave symptoms and knew before the head was completely removed from the block.
I hope my remarks above did not sound like I was suggesting that using oil type not recommended by the manufacture was a good thing! Just that just because it might not cause a major failure in the first five minutes running that it still was not a good idea.
No, I understood what you were saying. Sometimes you have to run what you got and other times you might need to cut a corner to make a dollar. What I was saying is that there might be a cost down the road to consider. I think we were on the same track.
I'm sure some Ubangie long ago filled it with whatever was cheapest.
Yeah , my first choice on Detroit oil is the Shell Rotella T1 30-wt . https://www.ruralking.com/rotella-t-30-wt-1-gal-bucket Then on the other hand when it was not available have went with the Shell 15/40 https://www.ruralking.com/shell-rotella-t-15w-40-motor-oil-1-gallon To be completely honest I never could tell the difference on oil usage . Mine are all natural asperated so that might make a difference . Certainly not disputing anyone's experience with this subject ! We all live in different areas & environments that we deal with . We still run 11 Detroit engines in our little operation . I'm also in charge of the warranty work …. LOL ! What the hell ? I aint gonna cover the warranty on that last 8-V71 …... You guy's are on your own ! Deal with it and don't call us . We will call you . HeavyEquipmentForums
A Detroit with black smoke and no power emergency flap is closed.it will run but smoke like crazy!!!seen too many times
Sorry it's been awhile since I've been in this thread and need to update it. We pulled the engine out as the dampner in the bellhousing was shot and we checked the injectors. Somebody had put 72 CC injectors in it when it actually needed 56. Runs like a champ with more power and no smoke now!
Hey the old blind squirrel finds another nut!
Imagine that: bigger isn't always better.
I realize this has probably been solved by now, but were any ports in the liners partly carboned up causing poor inlet air swirling therefore reducing scavenging? the airbox covers can be removed to get a look at the ports. you can't see all around the liners but the ones closest to the covers will be visible (may need an inspection mirror)
We didn't tear that deep into the engine we just replaced the damper in the bellhousing and then put injectors in it while we were there.