First, follow the traditional principle of up and down eight characters, and then see if there are any corresponding signs nearby.
Domestic cars are generally marked on the engine and timing belt. Just aim at them.
On the valve cover, it is still symmetrical at two points.
Check whether the crankshaft is aligned and whether the four pistons are horizontal. If so, please use special tools for timing. No, look at the top dead center of a cylinder. The camshaft of a cylinder does work.
Don't start the car when it is flooded. Remove the spark plug, add more motors, then install the spark plug and start it.
The so-called timing is the correction of the best time points of intake and exhaust, fuel injection and ignition.
If connected by belt, align the timing marks of camshaft timing gear and crankshaft timing gear with the timing marks on cylinder head and cylinder respectively.
If it is a chain connection, align three chain lobes of different colors on the chain with the marks of camshaft and crankshaft timing gear respectively, and some have a single camshaft, only two points need to be aligned.
If the camshaft is centered and there is no chain or belt, there must be an idler.
The official points of gears are marked on it, aiming at the camshaft and crankshaft respectively.
If the car is a diesel engine, adjust it according to the third point and aim at the timing gear of the injector.