Originally Posted By: Quest
Originally Posted By: Inspecktor
Yes, but I think some gets into the oil and can cause issues, the same way diesels generate soot in the exhaust, also ending up in the oil.
Just like sub-micron level diesel carbon soot: if the gasoline DI engine particulates are sub-micron level (more like exhaust-related health hazards), I wouldn't lose sleep over it RE: mixed in oil causing wear.
Afterall: anything less than several microns will be sufficiently suspended by oil and still provides sufficient lubrication and not exhibits wear.
I'd still be more worried about anything over 10~15microns level, which most qualified motor oil filters can still do a mighty fine job in this regard.
Now, I'll see if I can get a copy of that SAE paper to study on the human respiratory related problem RE: sub-micron particulates from the exhaust (not oil).
Oh and BTW: on the timing-chain related subject matter: no matter how you dice it: timing chain will stretch and wear over time (unavoidable).
Some may exhibits more stretch due to the way the engine was designed and executed, some exhibits less. Motor oil have a play in this game but granted: you use high-quality motor oil, change your air filter regularly and with conservative OCI, your engine timing chain will still likely to outlast the car body.
and if you want more, consider diesel-soot laden motor oil in ole MB diesel passenger/trunk where their engine, mostly driven by timing chain, can regularly if not easily reach 1/2 a million or even a million mile w/o the need of timing chain replacement (stretched? yes).
So, given all else equal: I wouldn't worry too much about those particulates in gasoline DI engine oil as a primary form of wear agent.
Q.
Chain stretching by mechanical tension promotes more wear than these teeny tinny particles.