bowhay

ok so i was recently given a 400sbc tht was locked up, i tore it down replaced the crank with an eagle, and replaced the rod bearings and main bearings and rings, as i was rolling over the crank to torque the rods, something hit and it wouldnt turn, i rolled it around the other way made almost a ful rotation and same story,i thought tht maybe it was hitting the cam because the timing chain was off at the time, so i rolled it over again till it hit and the cam could spin freely, so obviously its not hittin the cam, none of the conecting rods are bent, no bent or broke valves....im confused here and could deffinately use any help u got

fast75vega

you sure you got the rod caps all on right.... ive seen people spin one around and put it on backwards and it did exactly what your describing

fla1976

I would guess that one of the rods is hitting the cam. I think it is either the number 2 or number 5 that must be ground down. If you pull the cam, you might find that it rotates fine. Put a little clay on the top of the rod bolts and you can see where it is hitting. You could try installing the pistons one at a time without the rings and rotate it until you find which rods are making contact. The contact could be at the pan rail. Sometimes they need to be clearanced. Don't get carried away though as you don't want to get into a water jacket .

johnracer

Could also be a counterweight hitting a piston skirt.....

Johnny