I wrote an article about five years ago that contains many details about the development and use of water injection during WWII. If you are interested, you can find it at
http://www.enginehistory.org/Frank%20Walker1.pdf
Water injection works best in supercharged engines by reducing charge...
"What is the largest number of cylinders ever incorporated into one engine?..."
Someone recently reported seeing a 56-cylinder diesel in a German aviation museum. Further investigation revealed it was probably of Russian design, intended for very large bombers. It may have found a more modern...
“In the case of the R-4360, the cylinder arrangement required a crankshaft set at a 120- degree angle. It was a bit of a nightmare to balance out.”
Please forgive me for arguing, but in the interest of accuracy, I thought it might be useful to explore the construction of the R-4360 a bit...
Most cylinders for a production aircraft engine: Pratt & Whitney R-4360, with 28 (4 rows of 7).
Most cylinders for a US-built aircraft engine: Curtiss Wright R-2160 "Tornado," which had 42 (6 rows of 7). A 70-cylinder version was planned.
As has already been pointed out, the R-2160 was...