Further discussion based upon my last thread about pushrod engines still being fun in today's world of high tech overhead cam engine design.
It is true that being able to operate the intake valve and exhaust valve seperately is a huge advantage, no arguing against this, and I'm not trying. I'm a happy luddite, but not an unreasonable one.
Okay, but just how huge an advantage is "huge?"
For example: the humble Honda CG single cylinder, the most reliable motorcycle engine ever produced, having a single cam lobe that operates both the intake valve and the exhaust valve.
Several years ago a hot rodded Chinese CG clone engine was setting land speed records in the hands of a racing team from Cleveland Cyclewerks. With a displacement of 229cc and head porting and a Mikuni VM32 carb it was dynoing about 23 hp at 9200rpm...which is about the same as a hot rodded SOHC Honda CRF230 engine the R & D of which is about 30 years younger. How is this even possible? Perhaps the sohc CRF230 engine is able to produce good low and mid range torque along with the top end hp while the CG230 engine is all top end?
Cleveland Cyclewerks is known for making junk Chinese bikes with junk Chinese engines, nonetheless they were able to set records in two different vintage air cooled classes.
https://www.youtube.com/watch?v=bMpQgrQtODkLow tech? Yes. Utterly obsolete for a performance mill? Evidently not.
In an interview the man who built the CG land speed record engine wrote, "Having a single cam lobe requires that both the intake and exhaust valves have the same lift and duration, not what one would expect as the ideal design for a performance engine! As development would reveal, this was not necessarily a deficit since most racing/performance engines breathe best with a very nearly symmetrical valve timing."
Source: RideApart
https://www.rideapart.com/news/254553/how-to-set-a-land-speed-record-on-a-3200-motorcycle/So someone more experienced than myself please explain how the land speed record CG engine was able to make so much power. Does it really come down to "since most racing/performance engines breathe best with a very nearly symmetrical valve timing?"
Perhaps this simple engine architecture is able to make good top end hp, but loses virtually all the low and mid range hp as a result, and that's where it's inferior to an engine design that allows for differentiation between intake and exhaust valve timing?