Posted: 3/10/2008 11:12:45 AM EDT
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I'm no expert at all things automotive but I try to do as much preventive maintenance as I can on my vehicle. This past weekend got me wondering about something. I was replacing the distributor rotor and cap and was taking a look at the engine itself. When the engine is running, is it sort of self-contained cycle that keeps it going? I realize that fuel has to be injected, but beyond that, is that it? Here's why I ask. I had the cap off and plug wires disconnected. Obviously the spark plugs ain't gonna fire because the wires have been removed from the distributor. But yet, the distributor itself is connected to a crank inside the engine and that's what keeps it going, yet at the same time that same rotation is responsible for creating the juice to send to the plugs. Am I missing something here? Do I have the process wrong? |
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The dizzy is spun by a gear which is connected to the gear on the camshaft, the dizzy also has a driveshaft that connects to the oil pump below, which powers the oil pump and gives you oil pressure. The dizzy is not self powered, the ignition spark is provided by an ignition coil which is controlled by an ignition module which controls dwell and other things. The coil sends the juice to the dizzy cap via a spark plug wire from the coil, the rotor of the dizzy then shoots that to the terminals inside the cap which have a spark plug wire connected on the outside, the plug wires must be on the proper sequenced terminals for the correct firing order, and the dizzy must also be timed to the engine by using a timing light to the the engine balancer. |
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For the engine to "run" it has to have fuel, air and a spark. When you hit the starter it turns the engine and the air and fuel are pulled into the chamber, when you turn on the key it energizes the coil which gives you a spark to each cylinder every time the points connect. It all has to work together. |
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The distributor is mearly a timing device. The ECU/coil create the voltage, while the distributor directs that voltage to the (only) spark plug in a cyclinder that is currently filled with a compressed fuel air mixture. The gears in the distributor make sure the timing relationship remains fixed (even when the engine is off). |
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I’ve probably got a lot of this wrong, but here’s how I understand it. When current flows through a wire it created a magnetic field. When you coil that wire up it concentrates the magnetic field. If that current is interrupted the magnetic field collapses which generates a high voltage spike. This is how your coil generates a spark. (The actual power comes from the alternator or battery.) The distributor is synchronized to the engine and it directs the spark (high voltage spike) from the coil to the appropriate cylinder in the engine. |
Not quite right, actually the ECM commands a signal to the ignition control module, and in the case of GM COP setups, it can operate without a signal from the ECM as it has its own independant crank and cam sync sensors, which then command the coil to energize. There are no gears within the dizzy just a shaft. The only gear is towards the base of the shaft which allow the dizzy to be spun by the camshaft. |
Well from the battery which is constantly charged by an alternator, which is spun by a pulley which is spun by a belt which is spun by the crank pulley which is connected to an engine balancer, which is bolted to the cranshaft. Actually power is from the battery hence why the engine will have power to spark to fire the engine during cranking to start the engine. |