As RLB engines exploit loop scavenging with both scavenge and exhaust
ports in the lower part of the liner, the fully gas-tight top ring significantly
reduces the lateral forces at the piston skirt in addition to reducing
the blow-by of hot combustion gases—both of which increase the
piston skirt life. The package can be applied to the engine either as a
full package or step-by-step (intermediate package) depending on
service experience with the liners and whether the general piston-
running behaviour meets today’s expectations. It is also possible to
replace individual original liners with loop-cooled units whenever they
need to be renewed; there is no problem in running loop-cooled and
original design liners together in the same engine.