lol, you made me look this word up.
I agree. What was the engineer that designed that smoking? I want some of that stuff!
The team of engineers that designed this series of engines were working principally under the direction of an engineering genius called Harry Ricardo, who in 1927(!) wrote a paper forecasting the limitations of the poppet valve and implying that the sleeve valve was the way forward.
He was instrumental in the advancement of the internal combustion engine and solved several significant problems. Out of interest, one of these involved work on the problem of detonation, his solutions where directly 'employed' by the Germans with their version of a methanol injection system (WEP in AH). He and Bristol, after expending millions of pounds making the sleeve valve viable were ordered to help Rolls Royce and more pressingly Napier who could not solve their problems with the Sabre engine (Typhoon / Tempest motor) which was needed for the war effort.
I do not know the expected lifespan of the valve drive gears Bustr, if that's what you are asking, but I can tell you that the overhaul interval for the Bristol sleeve valve series of engines was
three times longer than that of its peers. Interestingly its peak fuel efficiency was also (approximately) at maximum power
The beauty of this design is twofold: there is far less power needed to actually operate the engine, and most importantly that the intake and exhaust ports are completely unobstructed when open, greatly increasing its volumetric efficiency.
The final iteration of this engine powered the Hawker Sea Fury. I trust you all know that aircraft.
I will upload some more material on the engine later if you are interested, some of it is hard to find but I needed it for a project.