I had to take apart my 2004 350z engine because I had a bad head gasket. I took the heads to a local automotive machine shop and had them check for seals and cracks. They did have to be milled because the heads were warped by 3000th I was told by the owner of the automotive machine shop. After I got them back I prep the small block and put down the new gaskets and laid down the heads and torqued the arp head studs in sequence to 92ft lbs . I then installed cams and tightened them down. I then installed the rear timing cover and the cam gears and chain, which I aligned up the cam gears on the left with the circles and the cam gears on the right I aligned up with the ovals. I then installed new water pump and the timing guides and new timing tensioner. Then aligned the mating marks on the timing chain with the cam gears and the crank mating mark.
Now my issue is the after aligning everything with all the marks mating up with each other and put a long screw driver to make sure the 1st cylinder was at the top. After doing all this I put the crank pulley back on before I put the front timing cover back on I wanted to make sure everything turned like it should but when I turn the crank pulley by hand it will only move about a inch and then stops like it's locked. Now the car is in neutral and I don't under stand. If all the mating marks are correct then none of the valves and piston heads should be hitting each other right? Please HELP......

 

Does it go backwards?

 

^^ Great question. It didn't occur to me to ask this, but it provides a lot of information.

"You know your stuff."

--Spike

 

You're going to have to confirm the position of each piston in relation to it's 4 valves then. Also make sure your timing chain is tight enough to spin without binding or jumping a tooth.

 

Yes it will go backwards and the timing chain is tight. I rotated it back wards slowly till it would not go any further and gave just a little pressure more but didn't want to bend a valve if that is what I was more then likely hitting so I stopped and went back the other directions till it stopped there while doing this I put a long skinny piece of metal down cylinder 1 and watched come back up to TDC and could here it push air out so I knew I was on compression stroke. I then looked down and the mating mark on the crank and it was matching up with the mating mark. I put a little oil over the cams lobes and matched up the all other mating marks to the cam gears and tightened up the tensioner. Everything was lined up correctly and I knew I was at TDC so I took a wrench and turned the crank by hand. Now it was stiff at first but started to loosen up and went completely all the way around a couple times. But every time I go about 180 degrees on the crank with the wrench I here a soft click noise. Do you think I damaged a valve or something. I was maybe thing it was the timing tensioner since it's controlled by oil pressure but not sure. I'm seriously worried I might have damaged something but I went so slow when turning the crank with the timing chain off. What do you all think and what would you do if you we're in my position?

 

You'll have to take the chains back off, then spin each cam by hand...First making sure the 3 cylinders on each bank are all down below TDC while you spin the 2 cams on either bank. Watch the cam followers closely to see if any valves are sticking.
Then spin the lower end, if there's a problem anywhere in the engine it should identify itself through this process.