Have a 6-71 natural that is blowing oil or fuel into exhaust bad. Obviously not sure if diesel or oil or both. Seems like oil and doesn’t smell like diesel, but motor doesn’t smoke @ all, runs good and fires right up in the cold. Checked blower and all dry in there. Had head redone and pistons & liners looked good from up top when head was off. Did not check injectors when they were out, but all tips seemed fine. Also running 40wt oil with .9 ash content. Thinking oil ring or injector?♂️ This is in a friction crane and doesn’t work hard like a truck. Any thoughts would be appreciated
My truck crane with a 6-71 will wet stack when sitting on a job site. I have to get it out on the road to get it hot enough to burn the oil out. I don't think you can keep it from wet stacking , if it doesn't work hard enough to get warmed up.
Those engine don't like to idle. If they idle, they will wet stack. Just the nature of the beast.
I get that not working the engine hard enough will cause this to some degree. I’ve had other cranes with Detroit’s and they never slobbered like this and think this engine didn’t always do so. Uses oil, but nothing crazy. Coats the whole back of engine with oil and makes a mess on deck.
This pic of that back of the engine doesn’t do it justice to the mess. This was before I pulled the head
6Ls notoriously slobber lo-load.
If the pistons/liners have some age to them, the only way to know for sure is by pulling the pistons. As long as you can remove the oil pan you can easily do in inframe, drop new pistons and liners in it since you've already gone through the head.
Drive it like you hate it. Had one in an old hustler readymix truck. The engine would hunt at an idle. The mixer was chain drive. When the engine loaped, it would give the cement drum a quick jerk, then it would rock back on the chain slack. With a load on, it would rock the truck, and slowly walk forward.
You should check the air box drain tubes AND remove the fittings they attach to, make sure those aren't plugged, Like I said... take the fittings out of the block and check them, they like to collect junk and bits of broken piston ring in the theaded end. Poking around in the block holes with a wire is a good idea too. Next pull an air box cover and check for gummed up, broken, or stuck rings. If the rings are good they will have a little "spring" to them if you push on them with a hard plastic tool of some kind. It's had to keep one of those 2 strokes from slobbering if they don't scream at full load most of the time.
Did you short any cylinders to see if you have a weak one?
Not that anyone would agree-But a 2 stroke installed in a piece of equipment that can't possibly work the engine like the engine requires, was and is a bad design.IMO
Back in the day that they were used, compared to the other engine choices available at the time, no other engine was more friendly to install in any application than the Detroit inline since they could turn CW or CCW, cam can go on either side of the engine, exhaust could go on either side as well as the blower, starter could go on either side, then there were the PTO ports to attach compressors, pumps, etc. No other engine was as versatile than the Detroit, and at that time they were very affordable. I'm convinced that's why so many were used. But that was then.
Yep... The first true "Modular" engine.
When everything is right on a 6-71 the only oil you should see will be out the air box drains. Is this slobbering out the exhaust port/s? If so, this is usually worn piston rings or blower seals. You can remove the air box covers and check your rings through the liner intake ports by running each piston to the bottom of its stroke. Take a small tip screwdriver and push on each ring. You should see minor movement and the ring should spring back into place. No spring back is broken rings usually caused by ether. To check your blower seals, remove the air intake housing off your blower and run the engine at idle. Use a flashlight and look inside the blower intake at each end of each rotor. You will see oil running from the rotor seals if they are leaking.
I understand the all the crap with salt water chevy's. My point is the manufacture didn't care because it was a cheap power pile. Instead of building from the power plant out, they built it then decided to use the cheap and easy . One reason a Detroit 2 stroke in trucks really don't work well is the idle time and the constant up and down on the throttle. It was and is a great boat engine, under steady pull on the prop.
I just remembered.....you can get oil slobbering from the wrist pin retainers if they come loose.
I beg to differ, it's not because they didn't care, manufacturers worked with what was available at that time. Take Deere, they fitted the 6-71 in their scrapers. Yes, Deere. Deere made engines at that time, been making them for years. But their engines, such as their AG engines, simply weren't a fit for their scraper. So what would be their choice, maybe a C-180 Cummins, but again, the Detroit was so easy to fit in any frame it was a logical choice, again, at that time. Same with manufacturers that didn't make their own engine, you could easily fit a Detroit into pretty much anything. I see it more as a production solution, not a "they didn't care" solution.
Some people like'em, but if anyone on here ever worked on a George Romminger piece of equipment with a two stroke you would learn to dis-like'em.
Oh yeah, the like/dislike debate is another thing altogether. My only point is I feel the manufacturers had to work with choices that were "available" at that time, nothing more.
There were other choices.
Yes, there were other choices, but none offered arrangements that were as versatile as the Detroit inline, none.
Ive got a yard full of the darn things.Even had chimney fires at times and black oil rain. As said above make sure the air box drains are clear.Broken rings and blower seals just need to be fixed. I have never filled mine over half on the dipstick. when i get a diligent new hand on a machine that actually checks oil and fills them to the brim we get a mess.Sounds haywire but it helps on a crane that never works.
You win willie59, but fact is years back any truck model could be bought for $3000 less with a 2 stroke so money is an object.
I like the 2 stroke Detroit’s because I’ve made a hell of a living rebuilding them for 30 years. LOL
Well, I did previously mention they were "very affordable"...at that time.
Money! LoL.
Very affordable doesn't mean it's good .
30 years ago I scrapped all my 2 stroke tools.
And Deere put Detroits in two ag tractors.
Back in the eighties I was working construction, the company had a 79 W900 with a 00-92 that was a total pos. It used a gallon or better of coolant a day it would run out the drain boxes/a constant steam vapor. The governor and rack linkage was so worn it it was slotted. One cold morning it was fired up on the job site and she started to roll real heavy and long. Then she took off for the moon smoking like hell. One of the operators yelled {Aren't you going to do something} I replied {Yah I'm going stand here and watch it blow}. --------------------- ----rod through the block she did. All the drivers were happy as could be to see it die.
That doesn't sound as much like a POS as it does an engine that is so worn slap out that it's begging to sling a connecting rod out of the block regardless of what brand it is.
I am a 2-stroke Detroit fan but I will be the first to say that in the old hoisting cranes in Minnesota that idled 99 percent of the time they needed a accessory that was never offered to my knowledge. In the winter the heaters never put out enough heat to defrost the window, even if you were careful not to breathe. Getting warm was not a option. They should have been built with a fire pit in the cab.
Nah- just dont' work when its cold. Or hot. Or raining. Or if the mosquitos are out. Shoot, just retire and fish......
The Detroit dealer here in Tulsa doesn't even rebuild the 2 stroke engines here anymore, they get sent to OKC. The last 2 engines I did were referred to me by them. There are still a lot of them out there still running and will be for some time to come.
Folks, the two strokes were a great engine when used in the right application, but it's a design that has to be loaded 95% of the time-it hates idle time and no load situations. There for it's a bad choice for equipment like a crane. In every aspect of manufacturing it boils down to money-it's always about cost to stay competitive and those engines fit the bill on cost. And I should have stated that better {The whole truck was a POS}. and yes it was worn out-the coolant that was poured in it everyday was worth more than the truck as a whole. Typical on site dump truck.
The 110s in the old Euc quarry trucks were slobber boxes, except when they came out of the hole then cleaned up, the same 110s series engine on a Fleeting Service tow boat would dribble some from air box drains but had no inclination to slobber as when stuck on a line of tows pointed Upstream were running props to keep tension down on anchorage lines, pedaling Downstream they were often shoving deep draft hulls thru the muddy bottom and still shoving hard or in maneuvering had prop wash to drive the boats sideways. Seldom were they left to idle for long periods except locking out. Can say they are quite a good marine engine, HATED Dirty conditions, were some OK in HE when were beaten on day in day out but again dirt would beat on them. The EMDs are a different breed altogether but just the same a Saltwater Chevy!! My own K100C 8V92 soured myself on DDs. FIRST Rule learned when taught to drive a DD in a 8664 FrtLnr, Open door, Insert Hand to door frame, SLAM Door THREE Times to be good and mad when drive the Shifter/Throttle.
Things don’t look that bad to me, but what do I know...
I've worked on and done inspections on more than a hundred cranes in my time and can say from experience that the choice of power plant doesn't make a lot of difference on the slobbering. Diesels don't make heat when run at idle and they all will wet stack and/or develop wet leaks over time. I've seen plenty of Cummins engines with coolant dripping down one side of the block and oil running down the other side. I've seen plenty of Cats with oil seeping out all the covers. I've even seen a few Mercedes engines with the bottoms blown out when they went from low idle to high idle with a load that they didn't want to torque through. And I've seen plenty of slobbering Detroits with caked up exhausts all because lift cranes just don't get a lot of hard running. The application is just hard on any engine. As to the subject engine, if it is running good and even on all cylinders, just button it back up and run it with a heavy load for a few hours and it should clean up. If you can't do that, then just get used to the idea that your engine is going to be messy. You can rebuild it and spend a lot of money but the engine will likely go right back to wet stacking.
I Agree JC. Let it drip, doubt will change anything with any work.
No one has mentioned changing the thermostat to a known good one. It may help maybe (probably) not.
After some thought and air box inspection, going to remove blower. Blower looked dry with a quick inspection, but suspect enough oil is getting by to cause this. Will update if that was it when finished. Appreciate all the help!!
The pics of the air box look too dry to me. I doubt the blower is the issue. Just sayin'.
At this point I would look at 2 things. Position each piston in its liner ports where you can see the very bottom ring set. Those are you oil control scraper rings......new/good condition scraper rings have an edge on the outside of the ring. If it looks like its flattened out (similar to the compression rings above it) then your oil control rings are worn. Worn rings can be from just normal wear, dirty engine oil being run, or dirt infiltration through the air cleaner/ blower. The only fix for this is piston kit replacements. The next thing is to remove your exhaust manifold. Look at all 6 exhaust ports and compare them with each other. Properly tuned Detroits (considering the compression is normal and even between all the cylinders) will look dry but carboned. If you see 1 or more that are wet with oil, those are your culprit cylinders. If they are all wet, you more than likely just have an engine that's is severely worn and needed overhauled. What you are seeing in the airbox pics is normal on high hour engines. You may have some blower seal leakage, but in my opinion that is not what is causing your issue. Again, make sure your airbox drains are clear. When the engine is running, you should feel air coming out of them.
Now that Ive had my second cup of coffee, I just remembered that I don't believe you can see the oil control rings in the liner port, the travel stops just short. Someone correct me if I'm wrong, its been awhile since I've done a 71 series. *NOTE* MY brain is dead today. Ignore this post lol Better yet...……...ignore everything I say today LMAO
Yea, they don’t come up past the ports. Don’t think its the oil rings. Cylinders look good and no signs of oil leakage. Engine doesn’t smoke one bit either. Had another mechanic look @ it yesterday and he was suspecting blower. Will figure it out, just hope I don’t pay for a new engine by then
Looks like an American in your picture. What kind of work do you do with it?Im running 3 Americans ,4210,4450,5530 and a Lima75C these days . The Lima has a cummins which was slobbering badly after a 3 month crane job , but cleans up well after a week of bucket work, The 4/71 s in my Americans all slobber ,but cleanup after a couple of days of bucket work when i get it with them. The old 30 ton in my yard is the worst as it just idles a lot. If you keep good strong batteries ,cables, starters and a starter button up front in the cab, shut it off as much as possible while your standing by.
I have an American and two Link-belt 218A’s. Detroit is in the link-belt. Mainly set steel. Try to keep idle time down, but crane didn’t use to slobber this much. Lower has a Detroit and will idle all day with out slobbering...
I see your point.This might be too simple but has anybody has messed with your emergency shut down flapper recently?Ive seen them do funny things besides just killing the engine.
Just curious if it started slobbering all at once or if it seemed to gradually get worse over time.
Not sure if anyone here has tried or heard of one solution to the slobbering of the 2-stroke Detroits. I was told one time that for one used in lightly loaded application one, I won't call it a cure but a work around, was to install restriction plates in between the exhaust manifolds and the heads. Basically say an 1/8 inch thick steel plate with a bunch of small holes. Idea was to create a bit of back pressure to reduce the amount of "cooling air" from the blower going through the engine that was keeping the cylinders too cold. Two problems I could see with this is first deciding how many and how big of holes to put in the restriction plates, guess it would be by trial and error. Second would be if you needed to get full power from the engine for a short time I could see it overfueling due to lack of air flow. Wanted to try this on a small genset with a 3-53 that was used to keep a big genset warm nights and week-ends and never needed even 1/3 of it's rated output but could not get powers to be to agree to a test of the idea. Instead they decided to just stick in smaller injectors, believe we went from N45's down to N-35's. But that did nothing in my mind because the governor was already adjusting the fuel output to what was needed to maintain the RPMs. Injectors only limited the maximum flow. If I'm off base with that logic I'm open to correction. If this idea would work I could picture an option of installing something like an exhaust brake in the exhaust where when max power was needed you could just flip a switch to open the butterfly to free up the flow.
Seemed to happen suddenly I think lol. It’s been that way for last two years and could run for another 10 that way I’m sure. Thought my operator said he had overheated engine, so I thought the head cracked and that was the cause. Had head redone and head was in decent shape when it came out. Checked blower real quick and dirty before I removed head, so thinking I need to check it thoroughly now...
Suspect not going to find much if anything, these get to an age just cold slobber and nothing will stop it.
Well if it did overheat it may have damaged some rings or the pistons where you could not see with them still in cylinders. I remember one 12V-71 we had that would run just great in a Haul truck once started, don't recall about the oil use on that one. Just needed a shot of go juice even on a 70ºF day. Finally at the end of the season it was brought in the shop and engine pulled. There was hardly any compression rings that were not broken! Started a bit better after new pistons and liners installed during overhaul!
The exhaust brake idea makes good sense. A lot of the newer trucks do the same thing for warm-up. But would it work on the 2 strokes?
On an inline engine, if the blower leaks it will puddle in the bottom of the housing after some idling time.
Would it work on the two strokes? Good question. By design, the blower is both exhaust and intake. Piston top goes below the cylinder ports, exhaust valve opens, the blower forces out the exhaust gasses from the combustion chamber, and just before the piston top raises and closes the ports the exhaust valves closes allowing the blower to give the combustion chamber a charge of air for combustion. I'm just wondering if restricting the exhaust ports of the head would adversely affect this process.
Thinking about it, I think it would tend to push condensed fuel right back through the cylinder ports into the air box. And condensed/unburnt fuel is the usual cause of slobbering.
I did just that. It retired a bit over 5 years ago January 11th. Debby and I don't fish all the time. We hunt and travel as well.
I like money $!
I put many a mile in an old "corn-binder hardtail" with a 6-71, man them things were loud... 'I SAID, BOY THEM THINGS ARE LOUD.' mumble mumble something about " cant hear out of my right ear " something something mumble!
It was always said that if you sat next to an old-school motor scraper driver in a bar to make sure you're sitting on his left side because he won't be able to hear anything in his right ear as a result of the Detroit Bark......
Earplugs were optional, a lot of guys would stuff cigarette filters in their ears or cotton balls from the wife's makeup kits, most of us just did without and "Huh, Whatsat you say???"
The "Mighty Roar of a [TS]24" - music to any engine aficionado's ears .........
Most of mine was from the Euc dump trucks at quarry or standing among the three 100s or pair of EMDs in a tow hull cleaning centrifugal filters out, the dropped wrenches in the bilges were always lost until a heavy service and bilge was pumped out.
Yup the bellow of the TS24 widow maker. The bellow wasn't the only thing that left an impression - on the other end the seat only had an inch of horsehair mat for padding.
Mine was the Euclid 74TD with the 12V-71 or the M50+M65 Mack with the 16V-71 with twin turbos, along with the little 8V-71 in the IR Drillmasters putting down the blast holes. There were a few others but those were the most common. Oh there was the 12V-71 Genset I was told to keep an eye on after I reported it was smoking a little on the left bank after they got it fired up. Sat in truck drinking coffee and had to call boss back a few minutes latter when one of the rods decided it wanted some fresh air!
Knew a guy that bought 6 P&H hoes with 6V-53's in them for digging pipeline. You had to talk pretty loud for him to hear you. I think they revved at 2650 RPM. 8 to 12 hours a day at full throttle I can only imagine. He went to Hitachi's with Isuzu's that revved about 1600 RPM and it was like heaven.
I asked my grandfather once why there was no muffler on the 6-71 in the rear of a TS-24, his answer: "so you know it's still running".
It had to be louder to hear over the front engine.
We never replaced any mufflers that rusted or rotted or were knocked off, Straight stacks on all, could hear the quarry equipment for five miles on a calm day INSIDE the hole. Seems IIRC the noise in the pilot house of a tow was louder from transferred vibrations than the actual exhaust stacks discharge, engine room just sucked.
Regarding American crane 7450. Here in Sweden is the type of crane very rare and not much knowledge to find. So, I hope you Americans can give some advice. We understand well the mechanical and the technical function of the sprag, clutch and converter but need to learn about known errors or defects. In what sequence, lowering-hoisting is the sprag engaged and disengaged? Does the sprag need to be dismanteld and cleaned. Any known sound or behavior from a faulty sprag? The hoist appears to be a bit sticky. We tightened the clutch but maybe not enough. Literature, tips and drawings are most welcome.
Not aware of Sprague Clutches on the hoists only in the engine drive, most were friction brake operated and designed for. Do you have ANY manuals on this?
Usually a Sprague clutch is used to catch a load and prevent it from an uncontrolled drop. I've generally seen them used for boom or load lowering on cranes and things like gravity boat davits that you find on ships for lowering boats into the water. There are some very good crane people here that can provide some of the maintenance information likely for this make and model crane.
One company I worked for had one of these noisy piles, except the stack was short and straight up so you could go deaf in both ears.
The progenitor of the Cat vibratory rollers. They were an easy machine to fix until the planetaries in the drum went bad.
You said a mouth full.
Even with that muffler would be loud enough to deafen on over a few months!! More a expansion chamber than muffler!
You can take that exhaust and pipe it clear to the next county and it won't help much. Those beasts are mechanically noisy.
You mean to tell me those Detroit’s at high idle aren’t music to your ears!? A fine tuned Detroit is like listening to Beethoven.
Huh? Whatya Say? !!!!!
Beethoven on drugs maybe
I still think one of the best sounds was from the 12V71N in the old Wabco B-70 scrapers, they had the Nelson manifold mufflers and a set of 5" pipes through the hood. They did bellow, but it had a mellow tone to it. And yes I sat on several of them for a few hours.
This song here was Beethoven's original version, hidden away for century's until Jeff Lynn of ELO found it in archives. Much better to listen to than a two stroke chevy. Beethoven was a ROCKER. Good thing Chuck Berry came along when he did.
Well, blower was redone and still leaking oil into exhaust. Not sure what to do now. Engine runs great though
Next suspect and only likely remaining, Is nothing else beyond rings that will do this and Not runaway.
Throw some STP in it. You'll be fine.
Was thinking sprinkle tspn. Bon Ami in the intake at High Idle!!!
You have severely worn oil control rings on one or more cylinders. Lucas oil stabilizer will help diminish the issue.
Interesting thought ... in attempt to re-seat the rings I assume? I've done that with a tspn. water to break up carbon build up ... helps stop engine from dieseling. But that trick needs to be done on a cold start.
Long ago unscrupulous used machine sales people would do this, I was being facetious. The old tricks were Bon Ami or Comet cleanser in the throat of a running engine to minimize oil use and blow by, banana peels and sawdust in differentials to quiet worn gears, 140wt gear oil in sloppy manual transmissions, all automatics got Type F to make the clutches grab better. Were others I found on purchase inspections.
saw dust and banana peals in rear ends , I do know that a small block chevy likes pieces of Oreo's at 3,500 rpm.
a foot of fresh snow and still falling; 150 mi away from anywhere and all ya got is what is in the truck one would be supersized what one can come up with just to get home. panty hose for a fan belt. ... if it is just one leg wouldn't that be a panty ho? hand operated the voltage reg. tie-wire for a carrier bearing - summer time coffee can for exhaust to get through scales black tape heater hose to get to town and on and on
1956 International in a snowstorm with a busted fan belt. 2 rubber rings from 5 gallon bucket lids around the fan, crank, and 6 volt generator. Limped 25 miles home at 20 miles an hour but I got there. Pulled the double, chain side wheel bearings out of my XR600 Honda race bike and used with a bolt thru them in place of the bad bearing on the idler pulley on the serpentine belt tensioner on my box van. Made it all the way across Montana on a holiday weekend with nothing open with parts.
I thought I read on here that there was a Cat procedure and part number for bon ami for rings that failed to seat. (failed to seat is different than worn out) To properly decarbon an engine, it has to be up to operating temp, and use a garden hose, light shower nozzle...
Are several 'Contestable' or questionable processes of years gone by that actually worked, they got edited out of the repair guides as the people that used them got out of hand with them. IE Gasoline for fuel gel control was in the Older Detroit manuals, no more than 5 gal to 100 of unleaded regular gas with a chart for mix rates against temperatures. All too many read/heard the first sentence then made a second mix without using as much fuel as possible and overloaded the diesel with gas as just mixed 5/100 and ate fuel systems up. The Bon Ami was in really early IHC manuals I remember as to seating Chrome Rings that would not seat and were using serious amounts of engine oil. My one boss had that manual for the old V478/549 series where was printed in it. And was "One level tspn sprinkled in the intake at 1500rpm Until severe smoking abated". Supposedly aided in seating stubborn valves as well but detracted on longevity per the boss.
The Bon Ami trick was widely used years ago, and like DM said with chrome rings. Those could be troublesome trying to seat.
Yes there was a Cat part number for it at one time! If I can find it I think I had an old manual that mentioned it.
I have seen high oil consumption through leaking/loose wrist pin retainers although it is not nearly as common.
Seen a couple of runaways due to badly installed wrist pin seals!! 53s were the worst for that.
Back when I worked for Terex dealer, we always checked the wrist pin retainers with a vacuum cup. We had a guy that built engines that was ALWAYS afraid to do an initial fire off of any Detroit he built. He had a few runaways and was gun shy as hell. He would build an engine and spend hours going over everything 3 times or more trying to convince his self that it was good to go. OK.....I'll admit some of his paranoia was caused by some of us in the shop screwing with him. LOL NEVER show a weakness around dudes in a shop. Things like pouring a half-quart of fresh engine oil under the engine he was running when he took his lunch break (we let him spend the last half of the day scratching his head trying to figure out where the oil came from)..... or another time he was running a new build, turned away from the engine for a few seconds and then some jack-off starts hitting a metal table behind him with a hammer( he almost broke a leg stumbling for the stop lever).......or another time when he saw a shop rag blow out of the exhaust on a fire up (stuffed in the port by another field tech). I just cant believe there are mean people in the world like that! Good times back then!!!!