If you do not have the cam hold down tools, Go here to make your own. Take only front valve cover off. Remove the front plug wires and the four bolts across center and one for the plug wire retainer. Next find a bolt that will thread into the hole between the cam lobes at the far left. This bolt will be 2.5 inches by 7/16 in. I think. Put the valve cover back on to drive to the store to get some bolts if needed. If not remove the oil from the threaded hole first before threading a bolt in. When you get the right size bolts here's where we start. My car is a 92 Z34 5 speed maybe all will be the same. Buy new valve cover gaskets (make sure they include the "O" hole gaskets), intake plenum gasket, Plenum to block water hose, T belt and Idler pulleys.


Part Numbers
Since I constantly have to hunt this down on the forums, here are the part numbers for what you will probably want to replace during a timing belt change.

timing belt - 24502982

tensioner pulley - 24503561 bolt - 10162013

idler pullies - 24503859 bolt- 11514441

tensioner actuator - 24503860

Instructions

1. Remove air-filter box and inlet hose. Then the overflow bottle for the coolant.
2. Remove the throttle cables from the throttle valve.
   Twist the shaft by hand and the cables will get some slack in them to work out of the release holes.
3. Remove the battery connections.
4. Remove connections from the two sensors on the back of the intake plenum right next to the PVC valve and remove PVC valve also.
5. Remove EGR valve (the mass located behind the PVC) by taking out the three bolts and the one wiring harness from it. Try not to damage the gasket.
6. On the passenger's side of the car, At the back of the plenum remove the MAP I think Sensor. Two bolts directly into the plenum and slide it out. You don't have to disconnect it.
7. Remove one bolt from the under side of the inlet to the plenum that holds the throttle cables. Bolt goes up and is a size 10MM. Remove plenum hose clamp under plenum inlet. This is a water jacket and a small amount of fluid will come out.
8. Remove two nuts over the plastic TDC cover on top of motor.
9. Remove all plenum bolts including two nuts on the rear valve cover.
10. Take plenum off remembering that a hose is connected in the front that will be hard to pull up.
11. Remove fluid from power-steering pump, remove accessory belt and remove lines from pump and nut that holds these lines to the top of the alternator.
12. Remove all plug wires from top of motor and just lay them back o*n top of the radiator support.
13. Remove front and rear valve covers and all of the plugs.
14. Remove upper plastic T belt inspection covers. only two bolts each.
15. Remove Accessory belt tensioner.
16. Remove the rest of the timing belt cover. I don't know how many bolts are there but don't pry on the thing just get them all out.
17. Spin the motor until the front head cam flats show up right and flat. Use the cam hold-down to tell if they are flat. Make sure they are flat. Bolt them down. Break the front cam cogs bolts loose and tap the back of the cogs with a hammer to release them. They will spin on the front of the cams.
18. Look at the crank and pay close attention where TDC is. If you don't get this right the thing won't run worth a shit. Here is where you have to correct yours for TDC. There is a pointer on the aluminum cover that points to TDC but there is a large gap from the pointer to the harmonic balancer and this is where I got the timing slightly off. I was going to put a screwdriver into the #1 plug hole and slowly turn the motor to TDC feeling when the screw driver stopped going up and then move the crank to where it just starts to go down. I was going to hit the center of the two positions I had found. This was going to be done with a wire bolted into one of the lower timing cover bolt holes and position the end of the wire as close to the balancer as possible without touching. This would ensure TDC and would give a closer pointer to the balancer. This would have to be done before the front cam was locked in place and the cog was loosened so you could turn the crank around a couple times.
19. With the front cams locked in place with the cam tool installed, Turn the crank one complete round until the rear cam flats are showing. Lock them down with the second tool. These flats are showing o*n the driver's side of the motor.
20. Remove the tensioner. It is on the back head by the strut tower. It is just under the cam cogs.
21. Remove old idler pulleys. Install new pulleys.
22. Book states to loosen the rear cam cogs but I could not get a torque wrench on them so I only removed one of the two.
23. Get a paper clip and the tensioner. The tensioner has a screw in the end away from the ball. There is a black plug in the side of the body that the paper clip will need to go into with the plug still in place. Tighten the screw and the ball will retract into the tensioner. When bottomed out insert the paper clip where you can pull it out when reinstalled onto the motor.
24. Wash hands. The belt instructions state DO NOT get oil on the belt. It will reduce the life of the belt.
25. Install the belt from the back head working around the system until it is all in place.
26. Remove the paper clip. Put a torque wrench on the tensioner pulley (square protrusion) and pull up with 12-20 lbs. of torque.
27. If you loosened up the rear cogs, tighten them before moving the crank.
28. Remove the tool from the rear head.
29. Spin the crank one rotation to TDC again. Tighten front cam cogs. This was easier with the car in first gear to help hold the crank in position. Remove front tool.
30. Spin crank 2 to 4 rounds by hand and then check the front cam flats are flush with each other to TDC. Spin one more round to make sure rear cam flats are the same. BE VERY CERTAIN THAT YOU HAVE THE CAMS on TDC AND THEY ARE EXACTLY THE SAME POSITION OR THE MOTOR WILL HICCOP AND BUCK UNDER ACCELERATION.
31. Install covers over cam timing belt area.
32. Install front and rear valve covers and spark plugs.
33. Install plug wires.
34. Install intake plenum watching not to break the gasket when putting it on and don't forget to line up the water hose underneath.
35. Install ERG and PVC and the connections to the plenum
36. Install MAP sensor.
37. Connect the battery and start the car. If all sounds correct at the rear (no miss) reinstall power-steering pump (fill after install) and accessory belt with tensioner.
38. Install air filter box. Should be done

Some things to look for

1. If fast idle after putting back together check the EGR gasket then the intake plenum gasket.
2. If bumpy under acceleration then the cams are not timed together.