BenzWorld Junior Member
Date registered: Apr 2011
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Adjusting the angle of the distributor by small movements make big changes! If I remember correctly, counterclockwise advances the timing and clockwise retards it (forgive me for not remembering for sure). Once adjusted. Having the timing mark on the pulley falls compared to the degree tab on the front of the engine. The ignition timing is correct if the two are lined up perfectly. You must adjust the ignition timing if they are not lined up. Your distributor timing is critical when the key is turned. Thats what allows resistance for the spark plug in piston 1 to fire correctly and on time.
The distributor is the nerve center of the mechanical ignition system and has two tasks to perform. First, it is responsible for triggering the ignition coil to generate a spark at the precise instant that it is required (which varies depending how fast the engine is turning and how much load it is under). Second, the distributor is responsible for directing that spark to the proper cylinder (which is why it is called a distributor)
The purpose of the ignition system is to create a spark that will ignite the fuel-air mixture in the cylinder of an engine. It must do this at exactly the right instant and do it at the rate of up to several thousand times per minute for each cylinder in the engine. If the timing of that spark is off by a small fraction of a second, the engine will run poorly or not run at all.
Ignition Timing is set by loosening a hold-down screw and rotating the body of the distributor. Since the spark is triggered at the exact instant that the points begin to open, rotating the distributor body (which the points are mounted on) will change the relationship between the position of the points and the position of the distributor cam, which is on the shaft that is geared to the engine rotation.
While setting the initial, or base timing is important, for an engine to run properly, the timing needs to change depending on the speed of the engine and the load that it is under. If we can move the plate that the points are mounted on, or we could change the position of the distributor cam in relation to the gear that drives it, we can alter the timing dynamically to suit the needs of the engine
When the spark plug fires in the combustion chamber, it ignites whatever fuel and air mixture is present at the tip of the spark plug. The fuel that surrounds the tip is ignited by the burning that was started by the spark plug, not by the spark itself. That flame front continues to expand outward at a specific speed that is always the same, regardless of engine speed. It does not begin to push the piston down until it fills the combustion chamber and has no where else to go. In order to maximize the amount of power generated, the spark plug must fire before the piston reaches the top of the cylinder so that the burning fuel is ready to push the piston down as soon as it is at the top of its travel. The faster the engine is spinning, the earlier we have to fire the plug to produce maximum power. Fuel that is unburned due to improper timing, lean fuel or clogged air filter causes too hot or carbon build up on spark plugs.
Last edited by THIS_GUY; 04-02-2011 at 08:28 PM.