Originally Posted by Paul_Siu
Is there some truth to this. This is the first time I heard of it.
Paul
Yes, a degree of conditional truth
In the perfect world, yes there is a microsecond where a "void' of lubricant could have an adverse effect but on planet reality these scenarios are the exception.
Basically there are 2 types of systems where caution is advised.
One is a true high stress/pressure machine where that millisecond void ( or dip) in lubrication can matter
The other is where inrush pressure ( and fluid density in a Poisson effect) can "crush" an empty filter ( sometimes happens on screw compressors)
Usually machines in these risk categories have safeguards like prestart flow pumps, running to temp/pressure before start or a no load ramp cycle , minimum pressure valves and so forth but you are better off filling the filter.
Whether that matters on an IC engine or not? I seriously doubt it and would need some detailed FEA to convince me otherwise.