How do you set the timing on a 05 ford transit 350 tipper 2.4litre diesel?

I have locked the diesel pump cog, the exhaust and the air inlet cog. how do i find the correct position on the crankshaft? I have tried 'top dead centre' it didnt work.
(the diesel pump has been repaired the timing chain and tensioner replaced) Would be grateful for any help.
Michael