'Well, the heart of it all is this cam shaft,' said Simnel, gratified at the interest.

But one essential part - the cam shaft - has changed little over time.

The cam shaft works something like a large, eccentrically shaped key that turns many locks simultaneously.

But when a car is being driven more slowly in town, the fixed timing of the cam shaft results in wasted gas and unnecessary emissions.

"I made my own intake manifold and cam shaft."

The engine again had some improvements including cam shafts to boost the power of the engine.

Cosworth also radicalizes the cam shafts and upgrades the exhaust system.

The cam shafts are slightly radicalized, and the exhaust system is upgraded.

Determined Realists: "I want to be a mechanic so there's no point in learning history because it won't help me change a cam shaft."

Liquid cooled double overhead cam shaft with four valve desmodromic cylinder head.