Motor problems
 

Hi everyone, I have a 01 Expedition with the 4.6L in it the original timing chain guides were broken so I removed them and replaced them did not touch anything else except what was required to remove the chains. Now I can not spin the motor with starter or manually does anyone know what could be the problem when I put a wrench on the front it turns only about an inch then stops I can back it up to the same position and it stops. I pulled the pan to see if there was anything damaged on the crank or rods everything looks in order. Any ideas?