Covering Exhaust During transtit

[mitch504]

Where are the Mythbusters when you need them?

Amen! You know,maybe if we could get a bunch of our members to e-mail them, we might see it.

 

[alelogman]

I'll cover them if I know I'm gonna get in rain on the trip. I just don't like the soot residue blowing everywhere...

This is not a soot thread but still, any idea on new tech for less soot?

 

[badazzboy123]

we once delivered a brand new 3800 madill shovel from eugene ore. to madills shop in kalama after my driver dropped off the machine the service manager called me to ask if we had taped the exhaust I told him yes he had,and that crumpled up ball of duct tape laying on the ground where the machine had been unloaded was the only thing that saved us from having to replace the turbo that took a dump after the machine was walked off the trailer. conclusion - TAPE IS CHEAP

 

[oregon96pd]

Not trying to argue but ive personally seen it happen. We pulled a motor out of a combine, put it on the back of a service truck exhaust side of turbo forward and hit the freeway with nothing covering the turbo. At between 40-45 mph the turbo DID start to spin, spun for three hours back there. Not sure if it would hurt it but i will always cover a forward facing exhaust, water isnt good inside an engine an duct tape is cheap. Call it what you want but thats just my experience

 

[muzy]

I taped or put a sock (bag with a bungie) on evrything that look me out of city limits. Reason, very little effort for peace of mind. muzy

 

[bobb]

i have heard that it happens. i have never seen it happen. could it somehow be that the intake side could see air pressure and spin the turbo? just a thought. get those dam mythbusters on the job.

 

[Scrub Puller]

Yair...Allis HD21's had no muffler and a curved forward facing six or eight inch exhaust. I heard the story back in the 'sixtys that the turbo could "windmill" on the float. Out of curiosity I checked it out by removing the concertina hose from the aircleaner on a couple of occasions when we got onto bitumen. I can report that at speeds of up to 32 MPH (as fast as the Mack would go)there was NO indication that the turbo would spin...that-is-to-say even giving it a flick to start rotation made no difference.

I do believe that extended trips on wash board roads MAY hasten turbo failure due to chattering of the shaft. Large turbo's used on low speed diesels such as Lister-Blackstones and English Electrics were fitted with a devise to lock the rotor during transit.

Just as an interesting aside. Turbo's run hot. There are not many applications where a 'dozer engine runs hour after hour at WOT and full load...scrub pulling is one and at night the turbo's on those old 21's would glow white hot/translucent and you could actualy see the rotation of the turbine through the iron casting...I have seen the same thing with a D343 in a trawler.

 

[TurboBarrier]

I've been hauling equipment for about 8 years now and I wanted to find a good alternative to duct tape, rags, tennis balls, coffee can, safety cones, buckets, hardhats, plastic bags and whatever else I could get my hands on to cover the turbo. I thought it sounded foolish but I complied because of fear of being fired or yelled at by a customer for not covering his turbo. (For whatever reason he may feel it need to be covered) I decided to make an easy to use vinyl cover and I call it a turbo barrier.
It comes with a small rubber tarp strap and is marine vinyl to withstand the weather! Check it out at Turbobarrier.com! Keeps customers happy (which is the name of the game) and is easy to use!

 

[Scrub Puller]

Yair . . . . TurboBarrier It's strange you should bring this up. I have noticed several machines lately with taped up exhausts on floats . . . when asked the drivers very seriously told me it was to stop the turbo's windmilling!!

I thought this B/S had been put to bed years ago. They'rs plenty of good reasons to cover a stack with your neat little doovery but spinning turbo's is not one of them.

Cheers.

 

[ben46a]

Whether it does or doesn't spin the turbo, covering the exhaust keeps customer quiet and liability off the trucker. It also surprises me how it seems that many people don't realize camshafts have valve overlap where intake and exhaust are open at the same time, albeit only slightly.

 

[Scrub Puller]

Yair . . . ben46a

many people don't realize camshafts have valve overlap where intake and exhaust are open at the same time, albeit only slightly.

I don't quite get your point mate?

Cheers

 

[Shenandoah]

I don't quite get your point mate?

I'm guessing he's referring to when both valves are open in the overlap position, which helps in scavaging the exhaust gases, there is a free path to open air on both the intake and the exhaust.

 

[Oxbow]

Years ago I ran heavy wrecker in the winters and towed a truck in backwards to the dealer without covering the stacks. After my boss paid for a new turbo we always cover the stacks.

Currently I rent a lot of equipment from Cat and us a Delo oil jug with the top cut off but the handle intack and a bungee cord to cover the stacks. The guys running the Cat dealer transports do this as well, so I figure there is a reason for it.

As many others have said here, it may not make any difference but it definetly doesn't take much time and it removes the liability.

 

[cdm123]

I only haul my own equipment and less than a houndred miles per trip, for twenty years if it's cold i leave it run, warm shut it off rever changed a rurbo yet

 

[trucker1]

Don't want to throw a downer your way, but I hoped you checked to see if anyone had a patent on that device, I have seen heavy haulers using one exactly like that only yellow about 10 years ago. If they never took the time to take out a patent, you are golden, if not, you could be in for litigation. When I first saw a guy use one I thought "what a great idea, I can make one of those". Never did, but it is a lot easier that using tape.

George

 

[busy dad]

We always covered the exhaust , except when the turbo was definitely blown.. If it wasn't covered the boss would explode.

 

[Randy88]

I've read and listened to this debate many times, but there are some things never discussed, the first one is, there are two sides to the impeller and both have to be free in order to spin, not just one, if there's an air lock on one side, neither will spin, now somewhere along the line there will be an open valve on both sides, but it needs to suck the air in through the air cleaner and blow/put it somewhere to allow the exhaust side to turn at all. I've also been told that's the reason why a 150 psi air hose won't spin the turbo, don't know if its a wives tale or not but can anyone clearify it??

The next one is, many turbo's have a weep hole in the exhaust side to elimate water from sitting in them and freezing the turbo in the winter, I've also been told that will decompress the air inside the exhaust side and not allow the turbo to spin at all, it'll suck the air from the path of lest resistance and not past the turbine per say, again this was explained in a shop class setting, again not sure if its true or not but how about it guys is it bull or not?

Another is wind speed, now since I"m positive everyone can's, caps or covers their exhaust whenever not being used, a windstorm or wind in general will do that same thing wheter its on a trailer going down the road or sitting on a jobsite, so explain to me why months of wind without a cover isn't the same as hauling it constantly for months down the road uncovered? If the wind blew 50 mph for months on end, would be the same as going down the road at 50 mph uncovered for months on end too and after decades of uncovered exhaust those turbos are still in service too?

The last one is temperature, I was told a long time ago, it takes heat to heat things up, turbo's don't spin at max rpm instantly on start up, they take time to wind up so to speak, and also cool and slow down at idle, I think it says so in most operators manuals, that's why you let the machine idle to warm up and also idle to cool down, to allow the turbo to slow down before shutdown, unless this is wrong and someone can tell me why. But I was also told that's why most turbo's won't spin fast if at all with just some low speed unpressurized wind blowing by the turbine, the turbo's are not hot enough to spin fast enough to ever wear out moving that slow, if that's the case they'd be shelled out constantly, because at shut down they're still spinning at several thousand rpm's until they spin to a stop after shut down. I"m not disputing what's been said, just adding some fuel to the fire of discussion to keep it going.

 

[Scrub Puller]

Yair . . . Good points Randy88. Back in the sixties Allis Chalmers twenty-ones came with a forward facing curved six inch stack . . . the boss even had them chromed.

The turbo spinning theory was around even in those days and I actually pulled the concertina hose and rode up there and watched the impeller. Admittedly trucks these days go faster but there was no movement at all at 35MPH.

At the time I put up the argument about a windstorm and all the turbos around the district windmilling and wearing out.

Of more concern, although in the case of small earthmover size turbos unproven, is turbo damage through the rotors NOT rotating during transit.

A good friend of mine took various pieces of plant into a now defunct uranium mine in the NT which involved about 350 miles of extreme corrugations (washboards?) and, in conversation with blokes at the site they were having a whole swag of turbo failures.

At that time I was just getting my head around low speed English Electric and Lister-Blackstone engines in a powerhouse. One of my first jobs was to fit a new turbo that had been shipped out from England and in the manual was a procedure to prepare turbos for shipping with drawings to make up fixtures and, with a dial gauge, centralise the shaft in the oil gap to prevent brinelling during transit.

So there you go. I figure those stories you hear about turbo failure after a long haul and attributed to windmilling have probably been caused by vibration.

Cheers.

 

[mitch504]

The thought about vibration making the shaft move in the clearance normally taken up by oil makes a heck of a lot more sense than a turbo spinning from air entering through the exhaust and leaving through the intake. Like I've said before, if that worked, I'd quit buying air filters. I'd just load a different machine everyday and pull the lowboy to lunch.

 

[FMD]

I've read and listened to this debate many times, but there are some things never discussed, the first one is, there are two sides to the impeller and both have to be free in order to spin, not just one, if there's an air lock on one side, neither will spin, now somewhere along the line there will be an open valve on both sides, but it needs to suck the air in through the air cleaner and blow/put it somewhere to allow the exhaust side to turn at all. I've also been told that's the reason why a 150 psi air hose won't spin the turbo, don't know if its a wives tale or not but can anyone clearify it??The next one is, many turbo's have a weep hole in the exhaust side to elimate water from sitting in them and freezing the turbo in the winter, I've also been told that will decompress the air inside the exhaust side and not allow the turbo to spin at all, it'll suck the air from the path of lest resistance and not past the turbine per say, again this was explained in a shop class setting, again not sure if its true or not but how about it guys is it bull or not?

Another is wind speed, now since I"m positive everyone can's, caps or covers their exhaust whenever not being used, a windstorm or wind in general will do that same thing wheter its on a trailer going down the road or sitting on a jobsite, so explain to me why months of wind without a cover isn't the same as hauling it constantly for months down the road uncovered? If the wind blew 50 mph for months on end, would be the same as going down the road at 50 mph uncovered for months on end too and after decades of uncovered exhaust those turbos are still in service too?

The last one is temperature, I was told a long time ago, it takes heat to heat things up, turbo's don't spin at max rpm instantly on start up, they take time to wind up so to speak, and also cool and slow down at idle, I think it says so in most operators manuals, that's why you let the machine idle to warm up and also idle to cool down, to allow the turbo to slow down before shutdown, unless this is wrong and someone can tell me why. But I was also told that's why most turbo's won't spin fast if at all with just some low speed unpressurized wind blowing by the turbine, the turbo's are not hot enough to spin fast enough to ever wear out moving that slow, if that's the case they'd be shelled out constantly, because at shut down they're still spinning at several thousand rpm's until they spin to a stop after shut down. I"m not disputing what's been said, just adding some fuel to the fire of discussion to keep it going.

Take a 200mph leaf blower and channel it into the exhaust of a ISX cummins. It spins the turbo..............Some of the tow truck drivers I seen will seem to reach speeds up to 200 mph...lol

150psi from a shop hose does not have enough volume due to the 3/8" or 1" air hose. It also takes volume to get the turbo to spin not just psi........