Valve hitting cylinder when trying to do tappet adjustments

[Tas]

Hi all,
I'll try to keep this brief but informative.
I've just finished doing the timing change after the crank seal was pouring oil.
After getting it back together it was running a rough and underpowered. I took the rocker cover off and it had lost a couple of caps. But more worrying trying to turn the crank by hand it would stop suddenly and not budge a little past TDC.

I took the timing cover off, took the rocker shaft out and spun it around to TDC and put the timing pin in the flywheel and injector pump. Alls lined up, including the cam marks - so why is it hitting?

I put the rocker shaft back on, torque it as per 300tdi instructions (5nm followed by 50 degrees) and again it hits something when the crank woodruff is at 12 o clock and the cam/pump are half rotation (11ish). I think it may be valve #4, but can't be sure.

Any suggestions? I'm a bit confused, if everything is lined up why is it hitting? Or is something else happening.

Thanks for any help.

[bee utey]

With the rocker shaft off, put a straight edge across all the valves and look for one that is distinctly lower than the others. You may have a bent valve or damaged valve seat if one valve is sitting too low.

[loanrangie]

With the rocker shaft off, put a straight edge across all the valves and look for one that is distinctly lower than the others. You may have a bent valve or damaged valve seat if one valve is sitting too low.

Could a valve guide drop ?