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Old 08-26-2000, 04:31 PM
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JCE JCE is offline
Down to the Wear Bars
Join Date: May 1999
Location: So Kalifornia
Posts: 2,189
I'm not a MB tech, but here is my idea of what goes on in an engine (hope I am right - this is what I told my kids when they got drivers licenses)!

The engine has a lot of moving parts used to get power to the rear wheels. At the top of the engine, a cam shaft (or 2 on Double overhead cam engines) and valves sit on top of a cylinder containing a movable piston, which in turn is connected to a crankshaft at the bottom of the engine.

The cam rotates and has egg shaped lobes that push down on intake valves to let gas be sprayed in to the cylinder by the fuel injection system (or carburetor), and likewise at a later time push down on exhaust valves to let exhaust out.

After gasoline vapor is let into the cylinder through the intake valve, the piston at the bottom of the cylinder is pushed up by the rotating crankshaft and compresses the gas for ignition by a spark plug. This ignition pushes the piston down, turning the crankshaft, your transmission, and your rear wheels.

The flywheel is attached to the crankshaft, and provides the inertia/momentum to keep the crankshaft spinning long enough to push the piston up to expell the burned waste gas out the exhaust valves and to the tailpipe.

All this is for 1 piston, and cars have 3 - 12 or more pistons, usually 4, 6, or 8 for most autos. Almost all the above working parts - fuel injection, ignition system, intake/exhaust valves, etc. - are controlled by a computerized engine management system on modern cars.

The timing chain is the mechanical chain that physically connects and coordinates the rotations of the cam shaft and valve train with the rotations of the crankshaft and pistons. If it breaks, these rotations are no longer coordinated, and the valves and pistons may collide, usually with expen$ive re$ults.

Now you know everything about car engines that I do. (For a nifty illustration and better description, after I wrote the above I found this site with a description, an animated illustration, and a 3D illustration!)

Hope this helps.

87 300E, 65k miles
Smoke Silver

[This message has been edited by JCE (edited 08-26-2000).]

[This message has been edited by JCE (edited 08-26-2000).]
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