RB211-524 as fitted to B747.
From RR Maintenance Data handbook: The QEC weight for the -524 is 13,636 lbs (6187 Kgs). The basic engine in Testable Standard is 11,000 lbs (5000 Kgs). I know that CX contended that the triple spool engine held onto it's SFC longer in service than comparable thrust two spool engines. They also pioneered some ultra longhaul sectors with -524D4 200 series aircraft and never had the need to invest in SP's. The fact is all modern engines are a far cry from anything which previously was available, well over 20,000 hours on wing being not a rare feat.