The S2000 engine's dual overhead camshafts feature a space-efficient cam-drive consisting of a crankshaft-driven, silent-chain primary drive and a geared-secondary drive. The chain, along with a chain guide and an automatic tensioner, is located in an enclosed gallery at the front of the engine block.
The primary chain turns an idler gear at its upper end, which drives the second stage-the intake and exhaust camshaft gears. The camshaft gears are smaller in diameter than conventional toothed sprockets, which allow the camshafts to be placed closer together, further saving space. Geared drives are widely used in racing engines because of their dependability and greater timing accuracy at high rpm.
Each camshaft gear is a split (scissors) type, consisting of two concentric, spring-loaded gears, set at a slight angle from each other. When engaging the teeth of the idler gear, the spring-loaded split teeth of the cam gear take up any backlash, ensuring smooth and quiet operation.
