Contents
Is spark advance the same as timing?
Ignition Advancing vs. Ignition timing is measured in degrees of a crankshaft rotation before top dead center (BDTC). Ignition timing advancing means that the spark plugs are firing earlier in the compression stroke, farther from TDC. The air and fuel mixture in the combustion chamber doesn’t burn right away.
Does spark advance increase with RPM?
RE: ignition advance as RPM increases The advance rate is not linear to rpm. The advance does not always increase with rpm, and at very high rpm, some engines respond to some top end retard.
What is the best spark timing?
That is typically 15-35 degrees before TDC (top dead center) of the power stroke depending on the engine speed. Best power is achieved when ignition timing is set to fire the spark ahead of time to reach that peak pressure at about 2 degrees after TDC.
What should my timing be set at?
When in doubt, total timing should be somewhere between 34 and 36 degrees. A typical small-block Chevy’s timing curve needs to be set somewhere in this range for maximum performance, when the engine is being revved at 3500 RPM.
What’s the average increase in spark advance per RPM?
Typically a spark advance of 1 to 1.5 degrees increase per 1,000 RPM is characteristic of an engine demand. Bill Jenkins and Larry Schreib also reported that range of values in their popular Pro Stock drag racing engine-building book The Chevrolet Racing Engine.
The amount of mechanical advance is dependent solely on the speed at which the distributor is rotating. In a 2-stroke engine, this is the same as engine RPM. In a 4-stroke engine, this is half the engine RPM. The relationship between advance in degrees and distributor RPM can be drawn as a simple 2-dimensional graph .
How does the electronic spark advance system work?
The electronic spark advance (ESA) system calculates duration for keeping the electric power on and the timing of ignition, and outputs an ignition signal depending on the crank angle. The ESA system detects the angular position of each cylinder based on the signal of the crank angle sensor.
What makes the Spark occur sooner during deceleration?
The distributor’s centrifugal timing advance mechanism makes the spark occur sooner as engine speed increases. Many of these engines will also use a vacuum advance that advances timing during light loads and deceleration, independent of the centrifugal advance.