American Motors: cars / cams, crank shaft, overhead cam


Question
Jim B,

Well, for a while now, i have been intrested in cars, and i was hoping you could answer me a question... What do the "cams" on a car do. what is their purpose...where are they? And another question is the headers...same stuff...where are they, what do they do, what is their purpose?

I appreciate your time and I am looking forward to your responce!

Thanks again,
Tim

Answer
Depending on whether it is overhead cam or a pushrod motor, the cam's location is different, but it's job is the same. It is connected to rotate in synche to the crank shaft, and that's what opens and closes the valves at the proper time. The cam has a series of egg shaped lobes that either move a lifter (in a pushrod motor) or push almost directly on a valve (in an overhead cam) with some older motors a rocker is also involved. http://howthingswork.com should have some pictures.