could some one please explain the operation and drive arrangments of multi-valve engines?

Answer 1

all engines work in the same way regardless of the number of valves, the camshaft is driven by a chain or toothed belt via the crankshaft and is geared to turn at half the speed.to explain the workings further would probably confuse a person with little or no knowledge of such things so have a look at the following link, http://auto.howstuffworks.com/camshaft.htm
rekon that should help.

Answer 2

OK, here's the scoop on 'multivalve' engines. We want to get as much air/ fuel in the cylinder when the piston goes down on intake stroke as possible. The problem is, the faster the engine runs, the less air is drawn because the air stretches. That's why dragsters use a 'blower' on their engines to cram the air in.You could use larger valves, And some engines do, but it has been proven that using two smaller valves in the place of one big one will do a better job and is more maintenance free than just one large one. And will actually let more air/fuel in than one large one. And with two exhaust valves, you can get the exhaust out of the cylinder faster also. It's sorta like the multi blade razors. The more blades the quicker the shave.