2.2 8V Hdi Timing Question

[Richie-Van-GTi 71 2 Cars]

My relay van has the old 2.2 8v hdi lump in (2002), flywheel has been replaced at some point and now does not have a hole that lines up for timing. Ever since I have had it the timing has never sounded quite right and its a bit flat. Is the timing performed at TDC on these? I am planning on doing it with a mdti if I can get the correct info. T.I.A

[welshpug 1,657]

they're pinned at the back near the driveshaft not the front like most XUD/DW10's.

 

they are only 104 bhp in a 2 ton+ van, so they'll never be particularly quick!

[Richie-Van-GTi 71 2 Cars]

I know where the hole is (sounds a bit ominous) the problem is the flywheel does not have a corresponding hole. I know it will never be quick, it just doesnt rev freely / cleanly. Its as if its a bit retarded. If I know its TDC when timed then I will just dti it through the injector hole and be sure its all correct.