Ooh. I hadn't seen this animated 4-stroke engine image. I agree, it's grand. Thanks for pointing to it. A wish list or shopping list...h'mm. Well, I suppose we ought to decide what we're after. Something between a representative schematic and an illustration, with elements of both, possibly centred around this 4-stroke engine animation? To add would be the intake tract (air cleaner, intake manifold) and the exhaust tract (exhaust manifold, catalytic converter, muffler, pipeworks). I would think it best to gloze over the fuel system to avoid the decision of carburettor(s) or fuel injection; the point of the exercise is to have an illustration of airflow through the engine as installed in the vehicle. Do you agree? —