How do you find top dead center in order to check cam timing on a 1990 Nissan 300zx?

get an indicatorto find top dead center of any cylinder first you need a dial indicator. if you're a serious mechanic you already have one, if your're not, a cheap-o can be had for 15-25 dollars, or if you want to make the investment, pay out $100 plus for a starret, wich is made in U S A and will last 3 or 4 generations. first remove the spark plug from the cylinder you'd like to check. figure out a way to anchor the body of the indicator somewhere on the car, with the stem down in the spark plug, the deeper the better. now get a big honkin breaker bar and a nut and get a good bite on your harmonic balancer. turn the engine until the needle starts moving on the indicator, when it (the needle) is turning clockwise, your piston is going up, when it is turning counter-clockwise your piston is going down. the exact spot where it changes direction is TDC (top dead center) now you can check the timing marks on your cam sprocket. I've never done a 300zx but most cars are timed to #1 TDC. good luck and don't break it.