Turn engine in normal direction of rotation (unless otherwise stated).
Observe tightening torques.
If fitted: Mark position of crankshaft position (CKP) sensor before removal.
Do NOT turn crankshaft via camshaft or other sprockets.
Do NOT turn crankshaft or camshaft with timing chain removed.
Valve timing procedures
Removal/installation of timing chain requires:
Turn crankshaft clockwise until crankshaft timing mark aligned with pointer  .
Ensure camshaft adjuster timing mark at 12 o’clock position  .
Ensure camshaft sprocket timing mark at 12 o’clock position  .
Align yellow coloured chain link with crankshaft sprocket timing mark  .
Align orange coloured chain link with timing mark on camshaft sprocket  .
Align orange coloured chain link with timing mark on camshaft adjuster  .
Reset timing chain tensioner  .
Lift pawl upwards  .
Push plunger into tensioner body in direction of arrow  .
Push pawl downwards  .
Retain in position with suitable pin  .
Remove pin to release timing chain tensioner plunger  .
What happens when your chain or belt breaks.
The timing of course becomes way off. Your crankshaft will always spin making the pistons move up and down. However the valves will remain in the position they were in when the belt or chain stopped working.
Half of the valves will be stuck open and in the way of the pistons. Not all engines, but most. The piston out of valve time will smash right into the open valve and bend the, The only way to fix that is to remove the head and place those valves.
If you think your valves might have been damaged.
Remove all the spark plugs, valve covers. With both valves in the closed position insert a compression tester hose in place of the spark plug and inject air into the hose and see if the cylinder can hold air. If both valve are closed and air can not be held, chances are you have bent valves.
Do you need special tools to time your engine? Not always, on all my post I'll indicate that in each post if you do or not.
But what are these special tools? Normally you would just line up some marks on the cam and crank gears and simply be done with it. However when these tools are needed they are very very important.
The last one I did was a 2013 Range Rover 2.0 Turbo with dual cams. There were not timing marks at all.
There is a small threaded plug on the back of the engine that I removed to insert a special threaded pin that would rest up against the weight of the crankshaft to prevent for DTC of the #1 piston. No further clockwise rotation would be possible. At that point I installed the supplied crankshaft lock by removing the starter.
Then you line up the back of both camshafts to a notch in each camshafts to each other that a flat tool connects to each cam so they are in line with each other. But first you would make sure both intake and exhaust valves are closed DTC of the cams.
And the last tool was to lineup the crankshaft position sensor.
The most important thing in any major engine work is to rotate the engine by hand at least two complete rotations. And do it easy and slow and with the spark plugs removed.
Why remove the spark plugs? you may ask. Simple, with the plugs in place you'll be creating compression, making the engine harder to turn by hand and perhaps giving you the misconception of valves hitting the pistons or is it compression.