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 

 

Hi Al

Check my logic and math here,  at 6000 RPM the rotor turns 2000RPM. The circumference around the ellipsoid is about 28 inches. 28 times 2000 is 56000 inches per minute, or 9000 inches per second. The chatter marks look on average say 1/8 inch crest to crest. 9000 times 8 is 72000Hz (ultrasonic)

 

Chuck;

 

56,000 divided by 60 is 933.  Times 8 is 7500 Hz.

 

Al