I am old and need big pictures.

 

Only on the irons with the gears?

 

Could be rotors too wide. Rotor gear has walked out of the rotor a ways and is draging on the irons.

 

Usually from over heated oil, or a massive over rev.

 

Could be carbon not removed from the seal grooves during overhaul.

 

It affected both rotors.

 

Could be the "Handedness" of the seal springs not observed during assembly, and the seals are walking backwards during running. Run long enough the "O" rings wear out and the engine starts smoking badly.

 

The major part of the pattern seems to involve only the inner seal. Can'y be sure.

 

Measure the height of the thrust lands on both rotors. Press the rotors between aluminum plates on a press before assembly. I also reduce the thrust sides a few thousandth to allow for more tip when screaming the engine. Also I remove .004 from each rotor outboard of the outer scraper groove.

 

Poor oil supply?

 

Oil pour weight too low for the application.

 

A random orbital sander with 400 silicone carbide paper and kerosene with cure most of it. If more is needed lap these irons against the center iron.

 

It does not look too bad to me.

 

Lynn E. Hanover