To make it easier to recognize the defects, I made a diagram – Valvetronic, Generation 2.
inner circle – (deterioration): speed of wear
middle circle – the impact of wear (absolute)
outer circle – the impact of wear (change of shape and individual impact to cylinders)
+ext – the impact of external conditions (oiling, oil pressure)
The speed of wear marks details, more subject to wear. Accordingly – if the signs of wear cannot be found on details, marked with red (inner circle), there is no reason to believe, that there will be significant wear of details, which are in the yellow or green circle.
Impact of absolute wear – remarks, how the wear of exact detail impacts the performance of Valvetronic. If the wear of hub is compensated (typically – using HVA), the impact of wear is classified as small.
Impact of change of shape. Characterizes exactly the circumstances of a small opening (idle, low required torque) and impact of the differences on them. This parameter is especially important in case of evaluating the permanent disbalance of cylinders. For surfaces, for which the high impact of shape is identified, comparison of the details has to be done.
This diagram shows:
absolute wear of ALL (except HVA) don’t give significant problems;
HVA – only part, which has high requirements regarding resistance, absolute and relative (between cylinders) change of parameters, and also the external impact (oiling) is characteristic to this detail. Additionally, we have to remember – exactly the HVA is an element, which ensures low “sensitivity” of other hubs to absolute wear!
Diagram of Valvetronic, Generation 1, look’s slightly different: