Remember those marvelous engines of yester-year, in the palmier, good old days – engines that idled so smooth you could stand a nickel edgwise on the air cleaner while they ticked slowly over? No, you don’t. There weren’t any such engines, and never will be as long as we have shuttling pistons, flailing connecting rods and spinning crankshafts. A reciprocating engine will always vibrate when it’s running, and not just because some parts go up and down or in and out.