replacing timing belt procedure question!

  • 300zxanderson
    300zxanderson
    Junior Member
    • 20
    #1

    replacing timing belt procedure question!

    In my Haynes repair manual it says i have to remove the valve covers and remove the rocker arm shafts. Now i did remove the valve covers and I'm wondering if its really necessary to remove the rocker arm shaft. If it is necessary to do so, what good does it do. I feel like its just a waste of time. i have replaced the water pump all the front oil seals, new crank gear for timing belt (which was a PITA!), new thermostat and about ready to put the new timing belt on. I don't feel like I need to take it off. But i defiantly could be completely wrong and thats why I'm asking.
  • 88sinZ
    88sinZ
    Senior Member
    • 2019
    #2
    The benefit of this is the rocker arms will not be under tension from the valve springs, setting the belt onto cam sprockets under tension is very, very, very difficult. I wouldn't do a T-belt job without doing this.

    Follow the procedure for removing the rocker arm shaft bolts - if done *incorrectly* it can bend the shaft. Re-torque the bolts in multiple small steps from the center to the outside, they only require 13-16ft/lb but i've snapped a few at 13ft/lb torquing them correctly.

    Ditch the Haynes manual and reference the FSM here: http://www.nicoclub.com/service-manu…=300zx/1988/EM

    Timing belt install is universal for these engines, it does not rely on your year of MFG or model. After install it list 22lb pressure for 0.5" deflection, just mildly pull down between the cam sprockets to test, don't set it too tight.
    Last edited by 88sinZ; 08-05-2016, 06:25 PM.
  • 300zxanderson
    300zxanderson
    Junior Member
    • 20
    #3
    thanks! is the point of removing the tension so you can turn the cams easily to adjust the belt or so they don't move? Could i just use a camshaft holding tool for this. I really don't want to break anything else on this car. need it before school starts.
  • 88sinZ
    88sinZ
    Senior Member
    • 2019
    #4
    The reason that you remove the tension from the shafts is because the cam sprockets will shift while under tension from the springs misaligning the sprocket.

    Remove the belt before you relieve the shaft bolts and you will see the cam sprockets snap out of position.


    There is no holding tool (I.e. Ford cam) that I'm aware of.
    Last edited by 88sinZ; 08-06-2016, 07:00 PM.