How does cam timing work for a car?
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The cam has an adjustable ‘relative angle’ compared to the crank position
In oldschool non-VVT engines it is simpler because the cam only has one fixed position relative to the crank. This can be adjusted, but it stays fixed and does not vary while the car is running. A belt or chain links them so they rotate together.
In newer cars with vvt it is more complicated because the cam angle relative to the crank changes and varies while the car is running, improving efficiency. A ‘phaser’ is often used to adjust the relative cam angle while running. This makes it more complicated to understand at first.
Try to understand oldschool non-VVT first and then VVT afterwards. Trying to understand vvt before non-vvt would be very hard.
For example, just look up a simple oldschool engine like a 351w or a 350 SBC. The cam literally just rotates along with the crank at a fixed position. You can shift the angle, but you only get to pick one angle.
Then compare to the similar but newer LS with vvt and phasers
If the cam is not adjusted properly the valves will be opening/closing at the wrong time relative to the pistons. Making adjustments to the timing can improve performance for specific applications.
In it’s simplest form on stock oldschool non-VVT it’s really easy you just line the cam and the crank up at the default factory setting hopefully marked on the engine. If the mechanic/manufacturer before you was friendly they would mark it so you don’t have to fuck around. And if it gets shifted off because of a slipping belt or something you just reset it back to the markings. But it can get super complicated with vvt and high performance tuning.
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