I have just done a headgasket on my 300e and i am puting everything back together but am having a problem. I cant turn my camshaft or crankshaft to set it to TDC(not strong enough). when i removed the head i did not remove the crank shaft and i put the timing chain on exactly as it came off so technically everthing is still in line exactly as it was before i took it apart. do i have to set it to TDC(the markings are off 1/2cm) or can i just leave it alone? if i do have to set it TDC, how do i turn the engine to move the cylinders?

thanks in advance