What is dwell on timing?
Dwell angle is the amount of time, measured as degrees of rotation, that contact breakers close in a distributor. Unless dwell angle is accurate, ignition timing won’t be accurate. The period, measured in degree of cam rotation, during which the contact points remain closed is called the dwell angle.
When do you set the dwell on a point engine?
You read above that the ignition timing is the last thing to set when tuning the engine. Your dwell, and thus your points gap, needs to be set before you get out the timing light. To set the dwell, remove the distributor cap and rotor, ground the coil wire and remove all the spark plugs from the engine.
How to set the timing with a Dwell Meter?
Hook up the other meter lead to a good engine ground source. For the adjustable window distributor, set the meter for the degree or “Dwell” scale. Place an Allen wrench through the adjustment window on the distributor cap, connecting it to the adjustment screw. Instruct an assistant to start the engine.
What is the dwell time on a four cylinder engine?
In a four-cylinder engine, the angle between each ignition cam lobe is 90° and the period of points closure or “DWELL” is usually a bit over 45° of distributor rotation. In a six-cylinder engine, the lobes are 60° apart and the dwell time is 30° to 35°. The dwell is adjusted by setting the points gap to a specified distance at maximum opening.
Why does too little dwell affect ignition timing?
Too little dwell gives the magnetic flux insufficient time to build up to the maximum. Both conditions give a weak spark which gets even weaker as the engine RPM rises and produces misfiring at normal operating speeds. The dwell, as well as spark plug gap, do have an effect on ignition timing.
In a four-cylinder engine, the angle between each ignition cam lobe is 90° and the period of points closure or “DWELL” is usually a bit over 45° of distributor rotation. In a six-cylinder engine, the lobes are 60° apart and the dwell time is 30° to 35°. The dwell is adjusted by setting the points gap to a specified distance at maximum opening.
You read above that the ignition timing is the last thing to set when tuning the engine. Your dwell, and thus your points gap, needs to be set before you get out the timing light. To set the dwell, remove the distributor cap and rotor, ground the coil wire and remove all the spark plugs from the engine.
Too little dwell gives the magnetic flux insufficient time to build up to the maximum. Both conditions give a weak spark which gets even weaker as the engine RPM rises and produces misfiring at normal operating speeds. The dwell, as well as spark plug gap, do have an effect on ignition timing.
How is the timing and dwell of a Motronic system controlled?
The timing and dwell of the Motronic system is controlled by its central computer, and cannot be adjusted. By far, the most important adjustment is the setting of the position of the distributor for adjustment of the timing. Make sure that your points gap is properly set (see below) prior to adjusting the timing of the distributor.