Just did some maintenance on my car including IMRC cleaning. I was extremely careful not to drop anything into the intake ports on the heads...I checked and double checked everything before re-assembly. Go to start it up, cranks once or twice, hear a very loud metallic noise and shut it off. I haven't tried starting it again, but I tried maually rotating the crank and it won't budge. Any thoughts? I really don't want to tear this thing all the way down :mj: