ThixO SYN MARYN Aviation Grease / Mobil 28 Compatibility testing
At the request of Bell Helicopter, MARYN research labs investigates the compatibility of ThixO SYN MARYN Aviation Grease with Mobilgrease 28.
A lot of bearings for Bell models come prepacked with Mobilgrease 28 and as Bell Helicopter would like to encourage the changeover from Mobilgrease 28 to ThixO SYN MARYN Aviation Grease without having to unpack and clean every bearing in the helicopter, members of the Bell Helicopter engineering department inquired about why the greases were incompatible, and what might happen if the greases got mixed accidentally. How much risk exists when some Mobilgrease 28 remains in the bearing after purging it with ThixO SYN MARYN Aviation Grease?
Most grease incompatibility results from chemical interactions between either the thickener or the base oil of dissimilar greases. Though the thickener systems of these two greases are normally incompatible, the fact that they both contain PAO base oil may suggest some level of compatibility. The MARYN research team performed testing on Mobilgrease 28, ThixO SYN MARYN Aviation Grease, and a mixture of the two to determine the degree to which compatibility may be achieved.
The research team conducted EP testing, characteristic testing of the mixed greases, 60 stroke penetration before and after heating intervals to 120 C , severe heating over 65 hrs at 155 C and the 4-ball wear test. All testing results indicates that due to similar base oils, MAG2/ ThixO SYN MARYN Aviation Grease are compatible enough to purge bearings and not worry about degradation of the grease and consequent detrimental effects on the bearings.
To view the full report click here.