hallo.have planned the head of the c20ne around 9/10tel, valves are regrinded, valve guides are shortened 5mm and the valve shaft seals are renewed.For good closure rub back on. now the problem: the engine runs shit.runs like estimated 70ps, squirts at full gas giving blue and stutters only quite reluctantly high. from 5000 tours like a speed limiter and at full load a ringing (despite super plus).have checked compression (13 bar), petrol pressure measured, ignition coil exchanged, plugs geta It could be that a valve shaft seal does not fit properly and it pulls so much oil that it can no longer run properly,there are also people who drive for better lubrication without vs seals.I don’t know any advice anymore…