Car overheated now crankshaft wont turn, help please

[ylw240sx]

Ok this is what happend. i was driving my 1991 nissan 240sx, and it overheated on me. i stoped for a while but I guess it wasent long enough. Then after i stoped i drove it and it was getting really hot. There was no sholder on the road i was on so the car died on me. Before it died on me it made a loud click noise. I found out that my head was worped and i needed a valve job. After i put it all back togather my crankshaft wouldent turn for a timming job. But it turned over before i took off my head. I tried putting it in Neutral and tried to turn it, but nothing happend. I think my bottom end proze on me but what i dont understand is that it turned over before i took off my head. So is there a trick or anything i need to do or any advice. Please help:( thanks

[C-Kwik]

Try turning the crank manually with a wrench. Try it in both directions. If it moves backwards and then gets caught at some point, something is interfering. Perhaps one or both cams may not be timed correctly.

[ylw240sx]

I only have the lower chian on right now i dont have the upper timming charin connected. and i cant turn it with a wrench.

[leper421]

Do you have the head on? Does it turn backwards? If you answered yes to both questions you may have hit a valve with a piston.

[ylw240sx]

no i cant even turn the crankshaft and yes my head is on

[yozsi]

if the cams are on and you dont have the timing right, you probably tourqued the head down on a valve. the bad part is that the head is gonna have to come back off.

[llamabeta]

You can't move it forward or back? Are you sure the pistons are stuck? The rings may have expanded and locked. If thats the case put some oil in the cylinders and let it soak for a day. Then try turning the engine. I find it hard to believe the crank went on you.

[ylw240sx]

ok ill try to put some oil on it and let is soak, what kind of oil should i use or does it now matter. I cant believe that the wrenk did that either. but ill try the oil and see what happens. thanks

[p00t]

if it turned after the car cooled down from overheating, theres no way the crank froze by itself.... its impossible, try taking the cams out so all the valves are retracted, and double check the lower chain you put on.

[llamabeta]

Doesnt matter. 10W30 Dino oil is fine. Even with the cams in place I'm suprised that you get no movement. Just to get them out of the way, take them off as recommended. That's a tough bottom end.

[ylw240sx]

ok after i sent the upper timming chain and valve cover, and everything else after that, i tried turing it from the iniction it turned. so ill have i have to do hopefully it sent the timming.thanks for all your advice.