Hi there and thanks for your hints.
I did normalize unorthodoxlly the timing with the old parts. The enigine runs normally again, no idea for how long but contemporary and for German technical inspection (11.2019) it could work. Furthermore the pressure (in German Kompression) of the 4 zylinders were measured, 13.5, 13.3, 12.4 and 13.1 BAR (metric unit), which seems to be quite or more than OK. I hope and think there is no bent (inlet) valve. What about the chain guide (plastic or pinion), which should be 3 years and 35.000km old.
I'd like to keep the Astra project small and do not want to open the whole engine (cylinder head etc.) , for what the car is worth. There is other things to maintain like 1 front drive collar, 1 convertibel hydraulic hose to the cylinder of the convertible hood cover. In the end you get another comparably good Astra for the price of 1000,- € without further repairing interventions on the market. The whople timing chain action will cost about 400,- € incl. men power.
BTW which chain preairing kits do you prefer, brand/quality/price. In FRG there is INA and Febi, but there is also quite cheaper sets of FAI and Swag.
What do you think and thanks in advance four your assessment.
PS: I hope my written English is comfortable to read and low in errors 🙂.
