Degree of Lubrication could certainly play a role, but I personally doubt

that it is the root cause - could be wrong about that, of course.  I believe

it may have to do with the amount of play in the rotor housing apex seal

slots.  I suspect that if the seals were pressing against the rotor housing

wall in the manner they were designed to - the rounded top tangential to the

surface of the housing - there is minimal drag and friction.  As the slots

wear the seals become able to "flop" from one side to the other of the

housing as its chamber undergoes the 4 cycles

 

Ed;

 

I’d agree that what’s happening is a vibration of the seal in the groove (wobble, or combination wobble-bounce), but I don’t think that is the root cause.  The spacing of the marks suggests a frequency of something more like a “squeak”, not related to the cycles of the engine.  The driving force for the vibration must be the friction on the housing wall. Even with a small clearance to start, it will get larger.

 

Based on the spacing of the marks, I estimate a squeak frequency somewhere between 6000 and 10,000 hz at 6000 rpm.

 

Since others use similar lubrication with better results, that MAY not be the problem; although there are a number of variables there.  The seal material (density, rigidity, friction coefficient; etc, would be critical.

 

This opinion may only be worth what it cost you.

 

Al