Dave,
I know GDI motors are relatively recent, at least in mainstream production, but all diesels are direct injection, so DDI.
The crankcase ventilation requirements have been about for at least 10, possibly 15 years. So all this time diesels have been dealing with oil vapour passing the inlet valves, without any fuel to keep them clean. We don't hear about the inlet valves caking up.
So why should GDI engines be any different? Doesn't make sense to me.
