Let's just take a look at a 4 stroke engine.

The 4 strokes are (1) INTAKE, (2) COMPRESSION, (3) POWER (4) EXHAUST.

Your timing is based off of the # 1 piston so it is very important that you know where it is and you use it to find Top Dead Center (TDC).
1) INTAKE- Piston is coming down, intake valve is open, fuel enters cylinder.
2) COMPRESSION- Piston going up compressing the fuel, both valves (Intake and Exhaust) closed.
3) POWER- Certain degrees before top dead center (BTDC). Spark plug ignites fuel, piston is blown down.
4) EXHAUST- Piston is coming up, exhaust valve is open and exhaust is pushed out.

With this in mind,
1. Take the #1 spark plug out.
2. Cover the spark plug hole with your finger or something to seal the hole.
3. Have someone turn the crank clockwise, when there is compression trying to blow your finger off, you know you are now on the compression stroke, and not on the exhaust stroke.
4. Stick a screwdriver in the sparkplug hole that will reach the piston top.
5. Turn the crank clockwise slowly, watching the screwdriver move up (or out). When the screwdriver stops moving, (up or out) YOU ARE AT TOP DEAD CENTER (TDC)
6. Now you need to turn the crank backwards (COUNTERCLOCKWISE) whatever degrees that you need the timing set at.

Your camshaft position sensor should be at a point to where the spark is made, if not then the one (1) bolt in the distributor shaft needs to be pulled up til lower gear disengages with camshaft, turn the center shaft to where the "C" is about 1/4" prior to spark position then lower the distributor back into place. You will notice that the center shaft turns as you lower it back into place. If you use the tool it will have the "C" in the correct position.


Hope this helps,

Joe