1) Remove Valve cover
2) Rotate motor to TDC (using flywheel marks).
3) Check to see that both cam lobes for #1 cylinder are facing up/away from the lifters
4) Insert your camshaft locking tool into the horizontal slot on the back (driver's side) end of the camshaft. If you cannot insert the locking bar, rotate the motor slightly so that you can.
At this point, ALL of your timing marks should line up. This means the following:
1) Camshaft is locked in place
2) Crankshaft is at TDC. Double check to make sure you have the correct timing mark. The real mark should be a "O", rather than a V-groove, unless someone installed a gasser flywheel on your car. In that case, the V-groove may be the correct mark. Some people have reported problems timing diesel engines due to swapped flywheels, incorrectly installed flywheels, etc.
3) IP pulley locked in place, with the timing mark on the inside of the pulley facing UP
If that all checks out, then you're good to go.
If not, then you'll want to loosen the tensioner, remove the bolt on the cam sprocket, and tap off the cam gear. There is a small hole on the backside of the metal timing cover where you can place a drift through, and knock the cam gear off. Once it's off, reinstall it with the bolt installed enough so that the cam gear still spins just lightly.
Once that's done, reinstall the belt, making sure there is no slack between the IP and the crank. Slip the belt over the cam gear and tensioner. Conversely (and easier in my mind), you can set the belt between the IP and the crank, then slip the cam gear into the top loop of the belt, and install it onto the camshaft, then install the bolt and lightly tighten it so that it still spins.
Once the belt is in place with the cam and tensioner roller still a little loose, remove the locking pin from the injection pump gear. Tension the belt so that you have about 45 degrees of flex on the belt, and tighten the tensioner. Then, using a counter-hold, torque the cam bolt to 45 nM plus about 1/5th turn. Do the same for the tensioner.
Removing the locking pin from the injection pump is critical, because with the cam loose and the IP free to spin, it equalizes the tension around the whole belt. Otherwise, the tension gets unevenly distributed, and it can affect pump timing.
Once that's done, you can double check your pump timing. If it's off, reset it to the low end of the specified range for better economy. Set it to the higher end for more power/better cold starts.
