That's quite the cost to brunt @nadvys and not surprised that Morgan's reaction was dismissive! The two different crankshaft sizes is a new one to me. Is there a way of forecasting time frames of the different sizes and if extra examination is in order prior to assembly? i.e. late 2013 motor and latest Centa version?
I'll guess that the early batches of Centas were silver without the jaw marks, this batch may have sealed oil better since the seal partially developed after installation; like Bleasey noted. Then came the black (hardened?) version with jaw marks; and most recently, after ~October 2018, another back version without jaw marks and a turned finish on the Centa journal's sealing surface.
Looking back at all the oil leak /oil seal failure threads on TM is seems like many could be attributed to the Centa version in black before October 2018.
