My favourite engine isn't a car engine at all. It's not even automotive.
It is the Napier Deltic.
A Napier Deltic is an opposed piston valveless two stroke Diesel used in marine and locomotive applications.
It is based on a German WWII Junkers JUMO design for an aircraft Diesel, which got paperclipped to England after the war and ended with Napier & Son, who developed and produced the engine.
It has 18 cylinders and three crankshafts forming a triangle, which gives the engine its name. This is an animation how the engine works in principle:
This is a diagram of the crankshaft arrangement:
To give you an idea of the size of the engines:
And this is the prototype of the class 55 'Deltic' locomotives:
22 of these locos were built by English Electric in 1961 and 1962. Each of them had two Napier Deltic engines with 1650hp each.
Edited by Junkman, 12 February 2012 - 03:25 PM.