If such a problem exists as a result of soft metal used for the sprocket wheel,
AND
the car has not been serviced every six months from new,
THEN
wear can be detected in the camshaft lobes.
IF
the car has had it's oil changed every six months, wear in the engine will be much less, because any stray metal particles will be taken out of the engine with the oil and filter change.
I am about to have the camshaft covers removed from my 1998 M112 V6 (because of gasket leaks), and I will instruct that the camshaft lobes be carefully examined. My car does not show even the slightest sign of blowing smoke, despite 215,000 klms covered. So that is a good sign.
It seems that the supplier, (or DB themselves), for sprocket wheels at the Underturkheim plant is where the engine components were made, and over a number of years, is where the problem may have originated. The problem doesn't normally show up until after 100,000 klms, and well outside the (then) standard MB warranty, so therefore DB were able to dodge the class action against them
It looks like the M112 V6, the M272 V6, the M273 V8, and the M156 V8 AMG engines were affected. Dates of engine build U]from[/U] around 1998-2002 to mid 2008.
Despite a lot of research, I cannot find any info that the M113 V8 engines were affected, but I have no idea why. They have a timing chain sprocket wheel, but they do not have a balance shaft sprocket wheel as well. (not needed)
The balance shaft in the middle of the 'V' on 90 degree V6 engines was needed to balance out first and second harmonics vibration on these engines.
The 90 degree V8's had no harmonic vibration problems in this regard.