Confirm the 3 yellow links on the timing chain. Install the timing chain and crankshaft sprocket. The first yellow link aligns the crankshaft sprocket timing mark. Note: There are three yellow links on the timing chain. Two of the yellow links (with a difference of 6 links) are aligned with the timing marks of the intake and exhaust camshaft sprockets.

When the engine speed drops, the variable valve timing regulator drops, the upper chain is loosened, and the lower chain acts on the exhaust cam rotation pull and the regulator's downward thrust. Because the exhaust camshaft cannot rotate counterclockwise under the action of the crankshaft timing belt, the intake camshaft is subjected to a combination of two forces: one is that the normal rotation of the exhaust camshaft drives the pulling force of the lower chain; the other is The regulator pushes the chain and transmits the pulling force to the exhaust cam. The intake camshaft rotates an additional angle θ clockwise, which accelerates the closing of the intake valve, that is, the intake valve late closing angle is reduced by θ degrees. When the speed increases, the regulator rises and the lower chain is relaxed. The exhaust camshaft rotates clockwise. First, the lower chain must be tightened to become a tight edge before the intake camshaft can be driven to rotate by the exhaust camshaft. In the process of the lower chain becoming loose and tight, the exhaust camshaft has rotated through the angle θ, the intake cam starts to move, and the intake valve closing becomes slow.

The following is the installation tutorial of the timing chain:
1. First align the timing mark on the camshaft sprocket with the timing mark on the bearing cover;
2. Turn the crankshaft so that the piston of one cylinder is at the top dead center;
3. Install the timing chain so that the timing mark of the chain is aligned with the timing mark on the camshaft sprocket;
4. Install the oil pump drive sprocket so that the timing mark of the chain is aligned with the timing mark on the oil pump sprocket.