Tommy Cookers wrote:but Buick (starting with desperate improvisation) took the world to a better place
Are you sure it is a better place?
Anyway, the Buick V6 was a 90° bank angle, so it needed the 6 crank throws to get even firing intervals. Not convinced on the balance front, as late model versions used a balance shaft are were still not the smoothest things around.
Also, to me the offset throw crankshaft seems to be at a disadvantage from strength and/or weight to the 3 throw shaft.
Tommy Cookers wrote:given the relatively low rpm-related loads inherent in the 2014 rules, the engines could be even more compact (than the 3 throw V6) if they had traditional co-planar (ie fork-and-blade or master-and-slave) rods, as last seen in the Martin V8 (or Harley D)
There is no advantage for the 2014 in making the engine more compact. The engine mounting face and gearbox mounting face have to be a set distance apart (300mm?).
The master and link rod arrangement (as was used in the 1931 version of the Rolls-Royce R) the short stroke would mean an unusual piston motion for one side.
Also, in the fork and blade system, the fork sections would be thin and have to use small bolts.
Martin V8, as in Aston Martin?
Tommy Cookers wrote:but that would disadvantage the 'MGUH design ?
I suppose the master and slave rod system would mess up the timing a little, but other than that I can't see how that would affect the turbo/MGUH.
Tommy Cookers wrote:modern bearing materials seem to allow narrower rods, so the co-planar benefits are less than traditionally (eg winning WW2)
Most WW2 era V engines used fork and blade rods, not master rod and link arrangements. Of course the Rolls-Royce Vulture, Exe and Pennine all used master and slave rods, but they were X-24s, with 4 cylinders hanging off each throw. All the radials, naturally used master and slave.
The Rolls-Royce Eagle XVI of the mid 1920s (proposed to the same requirement as the F, which would become the Kestrel) was also an X engine, but with 16 cylinders. This had each pair of banks connected to fork and blade rods with two such sets side by side on each crank throw, meaning that the lower cylinders were offset from the upper cylinders. A similar arrangement was found in the Allison X-4520 of the late 1920s.