Quote:
Originally Posted by babymog
The trap-ox was though never on the inclined-injection engines, but both timing specs were.
|
Not to say the trap-ox bent rods, BUT MB did not want to go through another massive payment to the EPA for yet again for diesel emissions. The trap-ox recall cost a heap of $ in parts and emission fines.
Quote:
Originally Posted by babymog
It stands to reason that several things would change to improve emissions, max. RPM is one of them as a diesel's emissions get worse as RPMs increase, a simple factor of not being able to speed up the flame front plus the port-effect of the injection pulse getting to the nozzle.
|
They did really play up the 603 series as a big leap in emission improvement.
Quote:
Originally Posted by babymog
Also, the timing device is mentioned. Unless I read it incorrectly, I believe that the advance curve of the timing device ends around 2200rpm, or at least below 3000rpm meaning that max. advance would be reached long before the max. RPM of the engine, and due to mechanical/accoustic/hydraulic/combustion constants would actually be more retarded at higher RPMs.
I'm not sure whether you're saying that these statements are directly from a book somewhere, or derived from data in some books, but am very interested to learn more about the source(s).
There are certainly documentable contributing factors to the rod bending, but many/most of these factors also were present in the 602.96 and 603.96 engines which did not tend to bend rods, ... we're missing the trail to why these factors didn't affect the many .96 engines but did the .97s.
|
Yes, MB issued a technical service bulletin for rod bending (internal notice to all dealers to fix a problem.) It was not officially released to the public (TSBs usually aren't) but somebody on one of the Yahoo diesel groups had a scanned copy of it. That was ~5 years ago and it may have been removed for 'copyright.' The production dates I have are on a DVD I got at the factory. I have tried to post parts of it on you tube but it's copyright protected and in PAL format. The EPC also has production run dates but you really have to dig to find them. At that time, I was in Germany seeing family, and an in-law who owns a garage. I tried to get some 350SDL parts from him for a customer. I then learned
from the factory the 3.5L was built for the US/Canada market - specifically the 603.970. SO...if we look at when the .971 and .972 came out (after the gasket redesign and RPM limitation)...the issue(s) were already corrected.
The .9
6X 3.0L have almost identical have almost identical parts to the .97X but IIRC the strokes and bores are not the same. That changes the load on the rods, perhaps to a point they can't take when the RPM is highest. Also, with smaller bores, a little gasket erosion would not allow a dangerous amount of oil in the cylinder. The bore difference was actually documented as a suspect cause. When we look at when and where the 'rod benders' came out, and when they were corrected, it makes sense as to N. American models bending more rods.
Truth is Mercedes or any car maker, is not going to voluntarily tell the public the whole story about any defects. A guy I used to know during high school is now a detective. We were shooting the bull one day a few summers ago. He compared detective work to counter-intelligence, "If you put the little pieces together you can figure out anything." I am convinced the factory was looking at multiple variables at the same time, and they suspected more than one cause. Sometimes we don't really need to see the
words in a TSB to know what they were by the
actions of the company. They replaced engines with bent rods (some out of warranty) and corrected/adjusted engines that hadn't yet bent them.