If you can't see any timing marks, using tappet motion isn't as easy as it looks - both valve are closed for a long time in these engines.
To help: the cylinders run in pairs. When one of each pair is @ TDC on compression (with both valves fully closed), its partner is @ TDC on overlap and has its valves moving in opposite directions. Pairs are separated by 3 places in the firing order (1 5 3 6 2 4).
Pairs are 1 & 6, 5 & 2, 3 & 4
Last edited by panic; Sat Apr 02 2016 08:41 PM.