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  #16  
Old 12-17-2004, 12:53 AM
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Sorry RT..

Hello rwthomas1
I am not nose-in-the-air regarding MB.
Sorry if my communication skills are low at the moment.
No two manufacturers create engines the same.
I have spent too much time in prototype and engineering to ignore small alterations, even on identical new engines.
Air flow, splash control, engine age and geographic location can have drastic effect even on a fully OEM engine.
Run away diesels are not advertised on the six O clock news, but they do happen more often than anyone liked.
The diesel manufacturers where happy to move to electronic injectors, and variable cam timing, this has almost eliminated the issue on all modern diesels.
Other brands with a long history of run away; Cummins, Cat and Detroit come to mind.
I would not call 100K+miles bad design, just the opposite.
On a new (under 100K mile engine) there is small risk, but all these vehicles are old and over 100K mile.
What needs to go wrong in the engine for your alteration to cause destruction???
Blow out the valve guides and seals = instant high PSI in crank case.
Cracked rings = instant high PSI in crank case.
Cracked head = instant high PSI in crank case.
There is such thing as direct turbo suction; the original placement of the oil separator subjected the separator housing and vent tube to intake suction.
Your alteration:
#1. Plugged the lower oil return drain.
#2. Removed the separator.
#3. Routed the valve cover vent tube directly to the U tube.
The concerns are Venturi effect, Siphon effect and Turbo suction, added to normal engine issues.
It is a free country, and it is your car, goodness knows I have created my own designs and tested them on personal cars, but those where cheap junk, bought for that purpose.
RE: The only thing I might consider is a 240 separator but I will still vent direct to the turbo inlet, if I can find a 240 separator.... Some people have the opinion that this will cause problems. I don't think this will and I don't plan on changing it any time soon. I knew this would start a fire.

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  #17  
Old 12-17-2004, 05:51 AM
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Quote:
Pictures tomorrow if anyone want to see that mod, cost me less then $2 for parts.
I'd be interested in seeing a pic of what you are talking about.
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  #18  
Old 12-17-2004, 09:58 AM
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Quote:
Originally Posted by engatwork
I'd be interested in seeing a pic of what you are talking about.
So would I, especially how you keep that hose away from the turbo.
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  #19  
Old 12-17-2004, 10:00 AM
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Here's the replaced poorly designed drain with clear plastic tube.

As you can see oil is draining back and it doesn't leak and hasn't for about 6 months & 6,000 miles.

You silly old fart, there is no turbo on a 240D.
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  #20  
Old 12-17-2004, 11:26 AM
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Quote:
Originally Posted by oldnavy
You silly old fart, there is no turbo on a 240D.
Alright, you got me there. I'm thinking I could do the same, but put a heat shield around the upper part of the hose.
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'89 Toyota 4x4, needs 2L-T
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http://i16.photobucket.com/albums/b1...oD/bioclip.jpg
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  #21  
Old 12-17-2004, 03:18 PM
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Heat shield may be wrong thing to do, it may help hold heat in line from oil. I have checked mine on several ocassions after 120 to 150 mile runs and the hose was never hot, just warm and one of those runs was in July here in the south. That picture posted above was taken just a few hours after a 125 mile run one way to MB dealer and then 125 miles back.

The only problem I have is the oil/air seperator is getting soft from being exposed to oil for so many years that I priced a new from dealer and was told about $100 for new one. That's when I came up with idea how to make a new one with filter, and was going to have the machine shop make up some for us.
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  #22  
Old 12-17-2004, 10:40 PM
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Oldnavy,
Reread my post: I didn't block off the crankcase vent, I just rerouted it direct to the turbo inlet.
whunter,
While I respect your opinion I still beg to differ. I don't see venturi effect as possible simply because for a venturi to work correctly the placement of the "suction" port is pretty critical, ususally on the curve of the venturi constriction. Siphon effect? I would expect that the normal suction created within the air cleaner housing would be much higher than this could be with a gas (vented blowby). Turbo suction creates a mild vacuum within the air cleaner housing. This vacuum is uniform within the chamber, there is no area of localized "super" suction. In the scenarios where a ring breaks, valve seals fail, etc. causing lots of blowby and increased crankcase pressure how is the little oil separator going to help? Its one little chamber and then it would dump out into the air inlet anyway. No way is a little 8-10oz separator with nothing in it going to pull enough oil out of a blowby condition serious enough to cause a runaway to do any good at all. And there is still no explanation other than the lame "different designs" answer as to why my other diesels and other MB's haven't had widespread problems. I'll take my chances thanks, RT
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  #23  
Old 12-17-2004, 10:53 PM
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Quote:
Originally Posted by rwthomas1
Oldnavy,
Reread my post: I didn't block off the crankcase vent, I just rerouted it direct to the turbo inlet.
Sorry, I thought I cleared that up in post #15, check it out. I guess I was trying to watch TV, read & post here and listen to the wife talk and got confused.
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  #24  
Old 12-17-2004, 10:57 PM
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Sorry, Oldnavy, recinded. RT
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  #25  
Old 12-17-2004, 11:05 PM
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  #26  
Old 12-18-2004, 12:14 AM
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Quote:
Originally Posted by oldnavy
Heat shield may be wrong thing to do, it may help hold heat in line from oil. I have checked mine on several ocassions after 120 to 150 mile runs and the hose was never hot, just warm and one of those runs was in July here in the south. That picture posted above was taken just a few hours after a 125 mile run one way to MB dealer and then 125 miles back.

The only problem I have is the oil/air seperator is getting soft from being exposed to oil for so many years that I priced a new from dealer and was told about $100 for new one. That's when I came up with idea how to make a new one with filter, and was going to have the machine shop make up some for us.
The separator drain seldom even has oil in it. A heat shield would be necessary to protect the hose from the heat of the turbine housing -- it's very close. If it were a problem for the oil itself, the factory steel line would have issues.
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'83 240D with 617.952 and 2.88
'01 VW Beetle TDI
'05 Jeep Liberty CRD
'89 Toyota 4x4, needs 2L-T
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http://i16.photobucket.com/albums/b1...oD/bioclip.jpg
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  #27  
Old 12-18-2004, 12:28 AM
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Last try.

Hello rwthomas1
Your decision.
At idle the suction - vacuum is small.
At full boost the suction - vacuum is high.
The turbulence caused by turbo spooling up is amazing.
The OEM air cleaner housing is large and well vented, it does not see vacuum, only slightly reduced air pressure.
The U tube is a tightly restricted turbulent air flow tunnel seeing direct vacuum at high boost.
The crank case is pressurized oil vapor = establishing flow to the separator, the heavy particles of oil swirl and merge into drops which return to the oil pan, it is amazingly well designed and effective.
Ask anyone on the diesel forum who had the separator drain tube become dislodged from the separator, how long did it take for your engine bay to become an oil soaked mess, the answer will shock you.

Last try to make clear:
Pressurized crank case establishes flow to your altered U tube, high boost vacuum occurs increasing draw from crank case, a couple of marginal exhaust valve guide/seals fail, adding more pressure and turbulence to valve spring area oil = sudden increased oil vapor flow into U tube and combustion chamber.
IF you are lucky, the first sign of trouble will be when the engine refuses to shut down, if you are not lucky, when you ease off the accelerator the engine will continue to accelerate to destruction.

With the OEM separator in place, you should have excess smoke and some warning, without it, all the oil blows directly into the combustion chamber and becomes unregulated fuel.

I have skill, ability and years of experience in my field, but NEVER will I claim to be able to predict when piston rings or valve guides/seals may fail.

Explanation of the lame "different designs" answer as to why your other diesels haven't had widespread problems, 1989' Volkswagen Jetta 1.6 N/A and 1993' Chevrolet C2500HD ExCab 6.5TD, these vehicles are next generation design and can not be compared with 1985 and earlier Mercedes Benz, that is the best I can explain without you taking 4700+ hours of design/engineering/mechanic training.
Other MB's have had widespread run away problems, just not advertised, that is one reason why pure mechanical injection diesels for automobiles are no longer made, and many new diesels have a flap to seal the intake.

The car is yours, as is the risk.
I wish you good fortune and hope it does not become a negative learning experience.
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  #28  
Old 12-18-2004, 01:27 AM
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Quote:
Originally Posted by oldnavy
The only problem I have is the oil/air seperator is getting soft from being exposed to oil for so many years that I priced a new from dealer and was told about $100 for new one. That's when I came up with idea how to make a new one with filter, and was going to have the machine shop make up some for us.
Same problem with my daughters 240D seperator.

Need oil seperator for 1983 240D

But here is what I did. I purchased "Plasti-dip" and put 6-6 coats of it on the front of the oil seperator. Did it over Thanksgiving and its has held up quite nicely. I actually had a hole in mine and it sealed it up and provided a good cover for the front of the unit.
First I washed the unit with a good degreasing soap to remove the oil and then coated it.

Dave
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  #29  
Old 12-18-2004, 01:52 PM
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Quote:
Originally Posted by dmorrison
Same problem with my daughters 240D seperator.

Need oil seperator for 1983 240D

But here is what I did. I purchased "Plasti-dip" and put 6-6 coats of it on the front of the oil seperator. Did it over Thanksgiving and its has held up quite nicely. I actually had a hole in mine and it sealed it up and provided a good cover for the front of the unit.
First I washed the unit with a good degreasing soap to remove the oil and then coated it.

Dave
Is this Plasti-dip found in hardware stores or parts stores?
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'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.
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  #30  
Old 12-18-2004, 03:24 PM
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Whunter,
Thanks for wishing me luck!
I still don't get how the air cleaner housing, that is inside the air filter once the air is passed through it, that area, the same area where the original oil separator lives (and vents to the intake air) is connected to the U-tube and cannot operate at a different vacuum level than the U-tube itself. I could believe this if the U-tube was long and very thin, then yes there would be a difference just because of flow restriction being unable to meet demand but this is pretty clearly not the case as MB never would have designed something so inefficient. I will say that air velocity in the U-tube is much higher than in the interior air cleaner area but that should be obvious. Vacuum however will be the same measured at the air cleaner lid or the U-tube wall close to the turbo inlet. I may even hook up a vacuum gauge and runs some tests. Regarding the design age and VW/GM's being 2nd generation.... Huh? VW's diesel dates from 1976 and GM's was designed by Detroit Diesel in 79-80. MB's first SD turbo was 79, right? Sounds like the same vintage to me.... While I realize that engines have different design parameters certain things should remain the same. Diesel engines usually create more combustion blowby due to high compression. Forced induction diesels create even more. That blowby has to be vented. All diesels will produce excess blowby if they have a mechanical failure such as rings, valve seals, etc. All diesels are vented at the highest point on the engine, usually the valve cover. Some designs vent directly to the intake manifold/turbo inlet. Some have an oil separator then vent to the intake/turbo. You still cannot explain to me how venting this blowby is okay in one engine and not in the other. If anything, the MB should be superior having less blowby, etc. since it was engineered to a higher standard to start with, right? How come if MB diesels running away, without any apparent issue, is such a problem you never hear of it on this board? I agree to disagree on this, RT

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