I found this info, copy and pasted it:

Hi, on the XN1P peugeot engine you want to line the camshaft mark just before the right hand side of the backing plate bolt ( at the 1 o'clock position). You want the backing plate bolt visible through the round cutout on the camshaft gear. The crankshaft gear is also set in line with the camshaft mark ( at the 1 o'clock position). I hope this helps.



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PS - To set the timing, you remove the tin plate on the top of the transmission and use the timing mark on the flywheel and the indicator. The #1 cylinder for timing is the one closest to the flywheel ( What would normally be #4) 15 degrees BTC for LPG.