Originally Posted by
DaveReidUK
According to Boeing's Aero, they don't.
Which makes sense - at takeoff N1. the markings are virtually invisible.
Well, according to several Boeing Propulsion types (and engine company types) I've talked to over the years, yes they do. Not so much at takeoff, but during approach/landing (the marks can be fairly dramatic at idle - especially the twirly ones)