Direct Injection - timing chain wear
12-28-2023, 03:25 PM
#1
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Thread Starter
Direct Injection - timing chain wear
I have been reading about the woes of direct injection and carbon buildup on the valves. I also ran across another interesting issue that should be an "additional" warning to change your oil frequently
The high pressure injectors that are now used in DI engines can actually leave small traces of unburned fuel on the cylinder walls. (Port injection had low pressure injectors). The traces of fuel is then picked up in the oil and forms micro-soot (they call it just "soot"). The particles are small enough to have no impact on moving parts with the typical oil layer separation, as is most of the engine, however, apparently the timing chain link pins can be ground down by this soot. This can allow the links to then be pulled ever so slightly further apart. The result is similar to a "stretched" chain, but it is not technically stretched.. just pulled a bit further apart at each link... this could lead to less perfect timing (likely without CEL) and loss of that "new car" performance..
This is just Another reason to "Change your oil frequently" as the soot is simply discharged within the old oil.
also short trips exacerbate the condition... while reaching operating temp regularly can remove some of the soot
The high pressure injectors that are now used in DI engines can actually leave small traces of unburned fuel on the cylinder walls. (Port injection had low pressure injectors). The traces of fuel is then picked up in the oil and forms micro-soot (they call it just "soot"). The particles are small enough to have no impact on moving parts with the typical oil layer separation, as is most of the engine, however, apparently the timing chain link pins can be ground down by this soot. This can allow the links to then be pulled ever so slightly further apart. The result is similar to a "stretched" chain, but it is not technically stretched.. just pulled a bit further apart at each link... this could lead to less perfect timing (likely without CEL) and loss of that "new car" performance..
This is just Another reason to "Change your oil frequently" as the soot is simply discharged within the old oil.
also short trips exacerbate the condition... while reaching operating temp regularly can remove some of the soot
Last edited by kafklatsch; 12-29-2023 at 02:04 PM.
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12-29-2023, 02:40 AM
#2
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MY'14 W212 M276 3.5NA @60kMi
the micro soot particles don't help longevity, these days MB is running low idle oil pressure that can lead to cylinder damages when superheat pistons produce cracks. Rest assured, that what warranties are for.
Some ppl report delayed hesitations when accelerating from idle....
Some ppl report delayed hesitations when accelerating from idle....
