From TDC the crank turns about 50 degrees then seems like its hitting something solid and stops. I decided to remove the rocker cover, loosened the cam bearing cap nuts equally and then it seems to turn fully with a little resistance at the 50 degree point. As soon as the bearing caps are tightened again the crank wont turn.

Any ideas guys?

It can only be hitting the valves. Loosening the bearing caps will allow the cam to float; and then not press the valves down as far, so you can get past the resistance.

Timing sounds wrong!

DON'T try and force the engine to turn, the VALVE timing needs to be re-set before it will turn with the camshaft bearing caps tightened.

If the engine has been run (or even forced round by hand) whilst the timing is 'out', it may well have bent some valve stems, necessitating the removal of the cylinder head in order to fit new valves.

Suggest that you take the following action:

Re-set the valve timing (Haynes Manual tells you how to do this)

Turn the engine by hand to make sure that it will turn through 720° (two full turns)

If it does turn OK, you can then either try running the engine, or carry out a compression test to verify that the valves are seating.

The great question of course, is why is the timing 'out'? Has someone worked on the engine or did it 'just happen'?

Regards.