How does the timing of an engine work?
For an engine to work at its best, the fuel /air mixture in each cylinder must fire just as the piston reaches top dead centre ( TDC ). It takes a certain time for the spark-plug to ignite the mixture and for the combustion to build up. This time stays roughly the same no matter how fast the engine is running.
What is the valve timing diagram of a 4 stroke engine?
As we all know in 4-stroke engine the cycle completes in 4-strokes that are suction, compression, expansion and exhaust , The relation between the valves (inlet and outlet) and piston movement from TDC to BDC is represented by the graph known as valve timing diagram.
When do you change ignition base idle timing?
Typically, when your car comes from the manufacturer, ignition base idle timing is set to a manufacture specification before top dead center. The timing advances as the engine’s speed accelerates, however, resulting in a variable that will need to be periodically adjusted using a timing light.
Can a vacuum advance change the engine timing?
The amount by which the two advance mechanisms change the timing is not adjustable. Some earlier distributors have a knurled nut on the vacuum advance mechanism, by which you can alter the timing as a whole (not just the action of the mechanism).
How does engine speed affect the timing advance?
The engine speed operating range affects where the timing is the best. Increasing the timing advance raises the high-end power, reducing the low-end. Decreasing the timing advance raises low-end power, reducing the high-end.
Typically, when your car comes from the manufacturer, ignition base idle timing is set to a manufacture specification before top dead center. The timing advances as the engine’s speed accelerates, however, resulting in a variable that will need to be periodically adjusted using a timing light.
Is the ignition timing too advanced or too advanced?
Ignition timing is too advanced at engine speeds below that and not advanced enough at engine speeds above that. Changing the timing value up or down changes the engine speed up or down for the optimum ignition timing.
How do you adjust the timing on a distributor?
The usual way of adjusting the timing is to slacken the clamping bolt of the distributor and turn the whole unit slightly. The amount by which the two advance mechanisms change the timing is not adjustable.