How do you adjust tappets on 8 valve scenic?

How do you adjust tappets on 8 valve scenic?
you will need some tools and valve clearance specification, i think you know that.here may be you are asking about the position of the crank for adjusting the valves. if it is rocker with adjusting screw you can adjust with that. if you have shims on the valve bucket under the camshaft then you can adjust by changing it to the proper size of shim.
adjust any valve which is loose, you can check if the valve can be adjusted or not by rotating the crank about 30 degree clockwise and counter clockwise from the existing position and if the valve does not start to open and stays loose then that valve is in good position for adjusting.
mark the Valves you have adjusted. rotate the crank one more turn and adjust the other valves. mark the valves you have adjusted.
if you have still some valves left rotate and make it loose i think this will help you somewhat.