If you've ever dissected a Russian engine, its absolutely fascinating! Since this is related to the competitiveness of Russian airliners, I'd like to add my insights.
1. The components are light! Everything that can be titanium is titanium. The first time I picked up a Russian external tube... I almost threw it not realizing it wasn't the stainless of a GE
/Pratt/RR engine. Also there aren't many bolts in a Russian engine (see next item). Heck, 1&2 make the engines very light for their capabilities.
2. If it can be welded shut, it is. Forget bolts... Its only the more recent comerical designs that have removable fuel injectors. There engines were simply designed to go hundreds of hours with multiple fuel injectors out (smoke? Comrade, I see no smoke). However, at the time the weld quality was in general superior to Western welds, most notably with Ti welds. (They were welding Ti alloys beautifully that weren't supposed to be weldable. If the part hadn't been in my hand...)
3. Forget LRU
(line replacable units). (see item 2). Want to fix the gearbox? Ship it to the factory as a saw is required. Assemblies that would be two to five LRU
's on a western engine were one monolithic LRU
(of course welded shut).
4. Forget getting 10K+ cycles between overhauls. Heck, forget getting the poor 3,700 of the old pw2038 (or the 8k+ of a CFM-56-3). We're talking 1K between breaking the engine casing. And those aren't bolts closing the casing (see item 2). Russians love their welds (and saws). Ok, there were some bolt flanges... but less than half of a western engine.
5. Emissions? Comrade, that is a Western lie!
Where did you learn that?? Are you implying that e.g. an AN-124 needs to have one of its engines removed after around 25 hours of flying?
Have you ever noticed those things fly around with 8+ mechanics? The engines tend to need a shop visit every few hundred flight hours.
Quite simply, Russian designs are always elegant. But the requirements for rough field operations kills their economics when operating in a Western environment. Not to mention the added maintenance costs. The aircraft techs were always amused by the water tanks in the Tupalov's (sp?) to correct weight balance dependent on loading. But I wouldn't want to be on a western jet taking off with a foot of snow on a dirt runway (a typical Russian design requirement).