[sedanbob]

If this engine was running before you pulled it from the car and put it on the stand, then I seriously doubt it is a clearance problem stopping the engine from rotating. The suggestions that something might be hitting on the stand, or possibly the fuel pump rod stuck, seem much more likely. Since the intake manifold is off, the possibility that something was dropped down an intake port. You said you backed off the rockers - are all the valve in a fully-up position? If not, something might be caught in a partially open valve, and the valve contacting the piston. If any of the valves are down lower than the rest, that may be your culprit. If you don't find something hitting the stand, or the fuel pump rod stuck, you will most likely have to pull the heads. If you find a stuck-open valve, that should at least narrow which head to pull. Good luck.

[sunrise7]

Thanks guys. Lots of things to check, but not much time this week. I do know for sure that its not a bolt in the crank flange or any interference with the engine stand. The engine has been sitting for a couple of years,, so maybe some rust up high in one of the bores where the piston is near tdc when it stops turning.... Guess I will have to pull the heads to find out for sure.... I highly doubt its interference with the cam since this motor ran before we pulled it out of the car.....

[hcompton]

Originally Posted by sunrise7

Thanks guys. Lots of things to check, but not much time this week. I do know for sure that its not a bolt in the crank flange or any interference with the engine stand. The engine has been sitting for a couple of years,, so maybe some rust up high in one of the bores where the piston is near tdc when it stops turning.... Guess I will have to pull the heads to find out for sure.... I highly doubt its interference with the cam since this motor ran before we pulled it out of the car.....

Yep its rust. You can try some marvel mystery oil in the. Plug holes and let it set over night then try to turn over with the plugs out. Mine stopped dead and would not move past some rust. But i was able to pull the heads and clean it out. Replaced the rings and hit it with a ball hone to make sure it was cleaned up and would let the new file to fit cast rings seat up. Not perfect but its not blowing smoke either im sure it will be smoking before it hits 100k miles but for now its fine.

Rust is very common there is always one valve open and leaves the cylinders exposed. To out side air and moisture.

Hope this helps.